Franklin Institute Library FHIL^DELFHI/I Class Book Accession Artic lk V. — The Library shall be divided into TWi/ classes ; the first l oinprisiii}; sueh work as, from their rarity ol" value, should not be lent out, all unbound periodicals, and such text books as ought to be found in a liWary of reference except Avhen required by Committees of the Institute, or by members or holders of second class stock, who have ob- tained the sanction of the Committee. The second class shall include those books intended for circulation. Article VI. — The Secretary shall have authority to loan to members and to holders of second class stock, any work belonging to the second CLASS, subject to the following regulations. Section 1. — No individual shall be permitted to have more than two books out at one time, without a written permission, signed by at least two members of the Library Committee, nor shall a book be kept out more than two weeks; but if no one has applied for it, the former bor- rower may renew the loan. Should any person have applied for it, the latter shall have the preference. Section 2. — A fine of ten cents per week shall be exacted for the detention ol' a book beyond the limited time ; and if a book be not re- turned within three months it shall be deemed lost, and the borrower shall, in addition to his lines, forfeit its value. Section 3. — Should any book be returned injured, the borrower shall pay for the injury, or replace the book, as the Library Committee may direct ; and il" one or more books, belonging to a set or sets, be lost, the borrower shall replace them or make full restitution. Article VII. — Any person removing from the hall, without permis- sion from the proper authorities, any book, newspaper or other property in charge of the Library Committee, shall be reported to the Committee, who may inflict any fine not exceeding twenty-five dollars. Article VIII. — No meinber or holder of second class stock, whose annual contribution for the current year shall be unpaid or who is in arrears for fines, shall be entitled to the privileges of the Library or Reiuling Room. Article IX. — If any member or holder of second class stock, shall refuse or neglect to comply with the foregoing rules, it shall be the duty of the Secretary to report him to the Committee on the Library. Article X. — Any member or holder of second class stock, detected in mutilating the newspapers, pamphlets or l)ooks belonging to the Insti- tute shall be deprived of his right of membership, and the name of the offender shall be made public. THE LEATHER MANUEAOTURE THE UNITED STATES; A DISSERTATION ON THR METHODS AND ECONOMIES OF TANNING. BY JACKSON S. SCIIULTZ. WITH NUMEROUS ILLUSTRATION'S. TO WHICH IS ADDED A KEPORT ON THE EELATIVE ECONOMIES OF BURNING T*^T SPENT TAN, BY THERON SKEEL, C. E. NEW YORK: "SHOE AND LEATHER REPORTER" OFFICE, 1876. PKEFACE. The proprietor of the Shoe and Leather Reporter pro- poses to meet a very general demand for information in regard to the manufacture of bark tanned leather by group- ing together in permanent form a series of articles on the subject, written for the paper by Mr. Jackson S. Sghultz. To make the work acceptable to the tanners, not only of Ameiiaa but of foreign countries, it will be appropriately illustrated, presenting in outline, and in some instances in working drawings, the principal mechanical inventions em- ployed in the business, so that the machines may be dupli- cated and the methods of their use easily comprehended. It was found inconvenient to illustrate the work during its publication in serial numbers, but now that it is to appear in book form that feature Avill be supplied, and will add to its appearance and usefulness. If the undertaking should be adequately encouraged by the tanners and finishers of bark leather, it will be followed at an early day by essays treating of " Sumac Tanning," and such other departments of leather and its fabrics as may be deemed worthy of consideration. New York, July, 1876. CONTENTS. Pase. Inteodtjction, - xai CHAPTER I. SELECTION AND CLASSIFICATION OF HIDES AND SKINS. 8IMILAEITY OF STOCK AS TO WEIGHT, SUBSTANCE AND CONDITION, HIGHLY IMPORTANT ASSORTING IN THE SOAK AND HIDE MILL HIDES SHOULD BE OF EQUAL CONDITION ON ENTERING THE HAND- LERS BREAKING THE NERVE IN CALF, KIP AND UPPER LEATHER IMPOLICY OF WORKING SEVERAL KINDS OP HIDES IN ONE YARD AT THE SAME TIME. I7 CHAPTER II. PREPARATION OF HIDES FOR THE BARK— SWEATING. COLD AND WARM SWEATING CONSTRUCTION OF SWEAT PITS — CLEAN- LINESS, LIGHT AND IMPENETRABILITY TO AIR NECESSARY IN COLD SWEAT PITS PROPER CONDITION OF STOCK BEFORE ENTERING THE PITS — CARE NECESSARY IN THE SWEATING PROCESS TREATMENT AFTER THE HIDES COME FROM THE PITS PART LIMING AND PART SWEATING GREASE AND SALT ON HIDES. - - - - 23 CHAPTER III. PREPARATION OF HIDES FOR THE BARK— LIMING. GETTING READY THE LIMES THEIR AGE AND STRENGTH — ^EFFECT OF THE LIME ON THE FIBER PLUMPING AND BATING PROF. LUT- EIN'S PROCESS — THE " BUFFALO" METHOD THEIR RESULTS HANDLING IN THE LIMES. - - - - - -31 VI CONTENTS. CHAPTEK IV. PllEPAEATION OF HIDES FOR THE BARK— FLESHING AND TRmMING. THE BEAM WORK CLOSE FLESHING, AVITHOTJT BREAKING THE GLUE CELLS — FLESHING LIME SLAUGHTER STOCK WORK TO BE DONE BEFORE LIMING FLESHING SWEAT STOCK IT SHOULD BE DONE WITH A WORKER THE GERMAN FLESHER — TKI5IMING CROP LEATHER AND BACKS ADVANTAGES OF TRISIMING UPPER AS WELL AS SOLE " ROUNDING" TRIMOTNG BEFORE TANNING BEST METHOD OF UTILIZING THE HEAD, PATE, ETC. - - - 38 CHAPTEE V. GRINDING BARK— BARK MILLS. THE INEXPENSIVE AND ABUNDANT POWER OF SOLE LEATHER TANNERIES GRINDING BARK FINE AND UNIFORM— USEFULNESS OF SCREEN- ING THE GROUND BARK THE DOUBLE- GRINDING MILL ITS EFFECTIVENESS WITH DAMP BARK THE ALLENTOWN MILL ADVANTAGE OF A STRONG MILL AND A WEAK COUPLER THE SAW CUTTING MILL A BARK CRUSHING MACHINE THE PROPER SPEED AT WHICH MILLS SHOULD BE RUN TANNIN LEFT IN THE BARK. - 4G CHAPTER YI. LEACHING. TANNIN VS. RESINOUS AND COLORING MATTER TANNIN REQUIRED TO MAKE GOOD WEIGHT EXTREME HEAT IN LEACHING INJURIOUS FLOODING THE BARK THE PRESS LEACH HEAT TO BE APPLIED ONLY TO THE WEAKEST LEACH CONSTRUCTION OF LEACHES CLAY AND LOAM PACKING FOR THE SIDES AND BOTTOMS WORK- ING THE PRESS LEACH THE SPRINKLER LEACH REVOLVING DE- TACHED LEACH. - -- -- -- -55 CHAPTER VII. HANDLING. THE HAND REEL THE ROCKER HANDLER ITS CONSTRUCTION AND OPERATION IMMERSED DRUM WHEELS A METHOD OF RAISING HIDES FROM THE HANDLER VATS — THE TUB WHEEL HANDLER HANGING HIDES IN THE HANDLERS — THE " ENGLAND " WHEEL HANDLING WITH THE COX ROLLERS. - - - - - G8 CONTENTS. TU CHAPTER YIII. HANDLING AND PLUMPING. TUK USE OF VEGETABLE AND MINERAL ACIDS THE EABLY USE OP VITRIOL BY AMERICAN TANNERS CONSIDERATIONS AFEECTING THE AMOUNT WHICH MAY BE USED ITS EFFECT ON LIMED AND SWEAT STOCK STRENGTH AND AGE OF LIQUORS TO BE USED IN THE HANDLERS DIFFERENCES IN THE HANDLING AND PLUMPING OF SOLE AND UPPER LEATHER. ----- . 76 CHAPTER IX. LAYING AWAY. TIME REQUIRED AND STRENGTH OF LIQUOR WHICH SHOULD BE EMPLOYED TANNING IN THE HANDLERS VS. LAYING AWAY EURO:^EAN METHODS " BLACK ROT " AND WHITE SPOTS THEIR CAUSES AND THE REMEDIES— SHOULD HIDES BE LAID AWA.Y GRAIN UP OR FLESH UP ? MAKING WEIGHT IN THE LAST LAYER. - - 84 CHAPTER X. DRYING AND FINISHING. WASHING AND SCRUBBING THE LEATHER — THE " HOWARD SCRUBBER " ^WHEEL OR DRUM SCRUBBING DRAINING HOW THE ADMISSION OF LIGHT AND AIR SHOULD BE REGULATED IN DRYING DAMPENING BEFORE ROLLING THE FIRST AND SECOND ROLLING — EFFECT OF THE ROLLING ON THE BUFFING QUALITIES BLEACHING WITH SUGAR OF LEAD AND SULPHURIC ACID— THE WARM SUMAC BATH EFFECT OF THE LATTER ON CALFSKINS, GRAIN LR^THER, ETC. - 94: CHAPTER XI. THE CAUSES WHICH AFFECT COLOR AND ASSIST IN THE MAKING OF A VALUABLE EMBOSSING GRAIN. WHY LEATHER SHOULD BE THOROUGHLY DRIED STRUCTURE OF THE GRAIN IMPORTANCE OF A PERFECT FINISH CARE TO BE TAKEN TO AVOID STAINS AND DISCOLORATION " CUIR " COLOR — THE NATURAL HEMLOCK COLOR " RUSSIA LEATHER " COLOR FRAUDS IN SELLING HEMLOCK FOR OAK LEATHER DURING THE WAR COL- ORING TO BE DONE IN THE HANDLERS EFFECT OF " STRIKING " THE GRAIN. ------ 103 Mil CONTENTS. CHAPTEK XII. CONSTRUCTION OF TANNERIES— THE TURRET DRYER. HOW THE ADMISSION OF LIGHT AND AIR IS CONTROLLED IN THE TURRET DRYER ITS CAPABILITIES FOR DRYING LEATHER IN QUICKER Ti:\IE, WITHOUT REGARD TO THE WEATHER ITS CONSTRUCTION, AND HOW ITS CAPACITY SHOULD BE PROPORTIONED TO THAT OF THE YARD HOW AND WHEN HEAT SHOULD BE USED HOW TO PREVENT DISCOLORATION OF THE LEATHER SAVING OF LABOR IN THE TURRET DRYER. _____ HQ CHAPTER XIII. CONSTRUCTION OF TANNERIES— PLANS, FOUNDA- TIONS, ETC. THOi;OUGH EXAMINATION OF PRESENT TTRUCTURES AND APPLIANCES ADVISABLE BEFORE BUILDING — rH OKTANT CHANGES FROM THE PRESENT GENERAL USE OF STEAM INSTEAD OF WATER POWER LOCATING ON "MANUFACTURING" AND " CULINARY " STREAMS A LOAM, CLAY, OR SANDY FOUNDATION FILLING IN BETWEEN VATS AND LEACHES WITH LOAM OR CLAY PLACING THE A^ATS THE "buffalo" vat— " BOX " VATS— THE PROCESS OF " PUD- DLING" IN SETTING THE VATS— UPPER CONDUCTORS SIDE AND END WALLS. - - - - - - 117 CHAPTER XIV. CONSTRUCTION OF TANNERIES— LEACHES. ROUND OR SQUARE LEACHES THE DURATION OF LEACHES ABOVE AND SUNK IN THE GROUND HOW TO BUILD A ROUND LEACH — HOW TO MAKE AND SET LEACHES IN THE GROUND THE CAPACITY OF THE SETS OF LEACHliS TO BE PROPORTIONED TO THE SIZE OF THE TAN- NERY. - - - - - - - 12G CHAPTER XV. CONSTRUCTION OF TANNERIES— FRAME WORK AlTD LOCATION OF BUILDINGS. WHY THEY SHOULD BE ONLY ONE-STORY HIGH FOR THE YARD AND BEAM HOUSE SAV NG IN INSURANCE BY S:^PARATING THE BUILDINGS CONVEYING LEATHER TO THE " TURRET " DRYER — TRANSMITTING CONTENTS. ix POWER TO DISTANT BUILDINGS PROPER SPEED FOR BARK MILLS AND ELEVATORS SIMPLE PROVISIONS AGAINST EIRE AND BREAK- AGE, AND TO PREVENT DUST. - - - - 134 CHAPTEE XYI. THE EOSSING OF BAEK. THEORIES OF THOSE WHO ADVOCATE BOSSING — ITS COST ^DIFFICULTY OF ROSSING WITHOUT TOO GREAT LOSS OF TANNIN STRENGTH OF LIQUORS WHICH MAY BE OBTAINED FROM ROSSED AND UN- BOSSED BAEK POSSIBLE ADVANTAGE IN ROSSING BARK FOR EX- PORT IN THE " LEAF." - _ . - - 141 CHAPTEE XVII. UTILIZATION OF TANNEEY REFUSE. BURNING THE WET TAN GLUE STOCK — -IMPORTANCE OF KEEPING THE PIECES PURE AND SWEET PRESERVING, CLEANSING AND DRYING THEM — USES FOR CATTLE HAIR THAT WHICH COMES FROM SWEAT OR LIMED STOCK ^WASHING, DRYING AND PACKING FERTILIZING LIQUIDS FROM THE LIMES AND SOAKS. - - _ 14(J CHAPTEE XYIII. TANNING MATEEIALS. DIFFERENT KINDS OP HEMLOCK BARK INFLUENCE OF SOIL AND CLI- MATE ON THE QUALITY HEAVY AND LIGHT BARK— VARIETIES OF OAK BARK THE " SECOND GROWTH " BETTER THAN THE FIRST GAMBIER ITS GROWTH AND PREPARATION FOR MARKET ITS COST COMPARED WITH THAT OF BARK VALONIA, DIVIDIVI, MYRA- BOLAMS " SWEET FERN," ETC. _ - . _ I55 CHAPTEE XIX. THE COST OF TANNING. THE SEVERAL ITEMS VARYING WITH DIFFERENT TANNERS DIFFERENCES FROM UNEQUAL WEIGHT OF THE COED OF BARK THE AMOUNT OF TANNIN IN UPPER LEATHER AS COMPARED WITH THAT IN SOLE LEATHER COMPARATIVE COST IN MAKING HEAVY AND LIGHT GAINS THE THEORETICAL STRENGTH OF BARK NEVER REALIZED • — COST OF "union" and OAK TANNING ^ESTIMATED COST OF TANNING IN EUROPE. - - - - - 169 X cc::tl!sT3. CHAPTEE XX. QUICK TANNING PROCESSES. CO^IMON KEEOKS OF THOSE OUTSIDE OF THE TRADE — HOW WORTHLESS PATENTS ARE MULTIPLIED EXPERIMENT IN TANNING BY HYDRO- STATIC PRESSURE ^VACUUM TANNING — DIFFICULTIES ATTENDING THIS METHOD HOW AGITATION OF THE FIBER FACILITATES THE PROCESS A GENTLE MOVEMENT, WITH OCCASIONAL REST, MOST EFFICACIOUS TANNING VS. TAWING. - - - 176 CHAPTEE XXI. THE SPECIES AND GEOWTH OP HIDES. " HEALTHY " AND " WELL GROWN " HIDES DIFFERENCF'^. IN HIDES AT VARIOUS SEASONS OF THE YEAR EFFECT OF CLIMATE AND FOOD ON TEXTURE AND GROWTH IMPROVED BREEDS OF CATTLE MAKE HIDES THIN AND SPREADY COLD CLIMATE MAKES A COARSE FIBER AND WARM CTJMATE A FINE TEXTURE EAST INDIAN, AFRICAN AND SOUTH AMERICAN HIDES — THE HIDES FROM THE EASTERN AND MIDDLE STATES AS COMPARED WITH THOSE FROM THE WEST- ERN PRAIRIES — CARE TAKEN OF CATTLE IN EUROPE. - - 188 CHAPTEE XXII. FRENCH AND GERMAN CALF AND KIP. WHERE OUR IMPORTED STOCK COMES FROM CAREFUL ASSORTING OF THE RAW STOCK TO INSURE UNIFOIiMITY IN WEIGHT, SUBSTANCE AND GENERAL CONDITION SOAKING AND MILLING BREAKING THE NERVE LIMING BATING AND WORKING OUT LIME— COLOR- ING AND HANDLING ^LAYING AWAY AFTER WORKING STUFFING DRYING SLICKER WHITENING BLACKING AFTER THE STOCK IS CUT OUT USUAL IN EUROPE VEGETABLE OILS USED INSTEAD OF FISH OILS DEFECTS IN FOREIGN CALFSKINS STEADY IM- PROVEMENT IN AMERICAN CALFSKINS. ^ - - - 194 CHAPTEE XXIII. GRAIN AND BUFF LEATHER. SPLITTING MACHINES MAKING SPLIT LEATHERS FROM GREEN HIDES OR FROM TANNED LEATHER EVERY KIND OF NATURAL GRAIN SUCCESSFULLY IMITATED STRENGTH AND DURABILITY OF SPLIT CONTENTS. xi LEATHERS THEIR INTRODUCTION TO EUROPEAN CONSUMERS ES SENTIALS TO BE CONSIDERED IN THE MANUFACTURE OF GRAIN AND BUFF LEATHER. - - - - - 210 CHAPTEE XXIV. CUERYmG AND FINISHING. THE STUFFING WHEEL AND HOW TO USE IT TO PURIFY AND CLEANSE DIRTY GREASE HOW TO MAKE STUFFING FLESH BLACKING FLOUR AND SIZE PASTES — HARM THAT MAY BE DONE BY DEPEND- ENCE UPON RECIPES DAMPENING LEATHER BEFORE AND AFTER APPLYING OIL AND TALLOW. - - - - - 218 CHAPTEE XXV. DIRECTIONS FOR THE CONSTRUCTION OF DETACHED FURNACES FOR BURNING WET SPENT TAN, BY THERON SKEEL, C. E. - - - 224 LIST OF ILLUSTEATIONS. Pack Cold Sweat Pits, --------- 249 Hide Mill, 251 Hand Reel, ----- ----- 253 Rocker Handler, - 255 Sole Leather Roller, -------- 257 Turret Dryer, -------- - 259 Sprinkler Leach, ---- - - 261 Bark Cutting Mill, - - - - - - - - 263 Allentown Bark Mill, ------- 265 Howard Leather Washer, 265 Salem Tan Press, --------- 267 LocKWOOD Leather Scourer, ------ 269 FiTZHENRY Leather Scourer, - - - - - - -271 BuRDON Leather Scourer, - - - - - - - 273 Stuffing Wheel, - - - - - - - - -275 Charles Korn's Whitener, - - - - 277 Union Whitener and Buffing Machine, - - - - 279 Fisk's Whitener and Buffing Machine, _ - - - 281 Union Leather Splitter, 283 Henry Labipert's Hide Worker, ----- 283 Outline and Trim of Hide, ------- 285 Tanners' and Curriers' Tools, ------ 287 HoYT Furnace at Wilcox Penn., Plates I, II, HI, - 289, 291, 293 Design for Wet Tan Furnace, Plates IV, V, VI, - 295, 297, 299 liSTEODUOTION. This Centennial year seems an appropriate perio:! in which to review the progress and present atfcainmsnt of the tanner's art in America. In the chapters which are to follow it is not proposed to give a chronological history so much as the general progress of the trade, and even that progress will be considered in subordination to the permanent advance- ment of the whole manufacture, rather than to the glorifica- tion of any special period of our trade history, or the com- mendation of any particular man or class of men, however conspicuous they may have been during critical periods. This purpose will make it unnecessary to iaquire whether "Simon" was a good or poor tanner; indeed, whether he was* a tanner at all, since, whatever his merits as an artisan, they have long since been surpassed by others with far better methods. For similar reasons no attempt will be made to bring un- der review the various exploded patents and so-called im- provements that have for the past fifty years been pressed on the attention of tanners. No volume, howdver large, would be adequate to contain the recital of their origin and pretensions. But so many of such improvements as have been at any time adopted by any considerable number of the trade— and particularly if they have a practical existence in XIV INTEODUCTION. any of our modern yards — will receive respectful considera- tion. Tliis, to be useful, must be candid, and free from ail bias. To intelligently contrast the merits of mechanical inven- tions — to hold an even hand in weighing the advantages and disadvantages of systems and methods which include among their advocates men equally intelKgent — is a task not likely to be accomplished without involving the writer in much cen- sorious criticism. But if an entire absence of all ownership or interest in patented or other improvements can qualify one for the task, then these chapters will contain a fair presentation of the merits of all claims. The form chosen in which to present this subject is intended to elicit honest inquiry and full discussion. Instead of a treatise giving in dogmatic language the processes which it is claimed tanners have adopted or must adopt, it is intended here to pre- sent the merits and defects of known systems and methods as their advocates would state them, and hold these up in contrast with other methods commended by equally intelligent men, and thus, by candid comparison, show their relative merits, and indicate such preference as may appear to be justified by our experience. This course of inquiry and presentation will, it is beheved, lead to far better results than if precon- ceived and fixed theories and opinions were enunciated and defended. In still other words, these chapters will contain a tolerant discussion of the present condition of the tanner's art in America, and, by way of contrast and honorable emu- lation, with the relative position of the same trade in the more advanced nations of Europe, and in the treatment of these subjects there will be no pedantic use of terms, either mechanical or otherwise ; only such plirases and words will be employed as are familiar to all practical tanners. While it is conceded that the tanner's art is largely chemical INTRODUCTION. XV in its nature, and may in tlie future be greatly advanced by the study and application of chemical laws, in this prelimi- nary inquiry it is thought expedient for both writer and reader to confine attention to the tanner's art as understood by ordinary workmen. It is proposed here to treat only of the subject of " tan- ning" as contradistinguished from "tawing." The art of " tanning " differs so widely from that of " tawing " that an expert in the one may be a novice in the other. They do not assimilate any more than the glove maker does with the boot or shoe maker. The latter uses " tanned," while the former uses " tawed " leather. Sir Humphrey Davy has drawn the distinction by the adoption of a chemical formula and test. He says, in substance, that leather is a chemical combination of gelatine and tannin, its characteristic being that, when combined, water will not separate the constituents or dissolve the connection ; whereas, in the tawing process, water will separate them and return the gelatine and salt or alum into their original elements. In America we have but little experience with any other than bark tannage, and, therefore, if we speak at all of the various substitutes for bark used by tanners in the old world, it must be from a very limited experience and a qualified knowledge. In deference to the success of the tanners of Great Britain we are compelled to admit that vegetable sub- stances other than bark — such as cutch, terra japonica, valo- nia, myrabolams, divi divi, etc. — do tan leather. These ma- terials practically do the tanning for Great Britain, and make a serviceable and even artistic leather. The barks of our forests, particularly those of the hemlock and the oak, are, then, only two among the tanning agents which are to be em- ployed in making leather. But as these are the agents with which we are most familiar — indeed, the only agents in gen- xvi INTRODUCTION. eral use in this country — ^it is with reference to their use that these chapters will treat, considering only incidentally such other tanning materials as come into competition. The only exception to the use of barks or bark extracts in this country is that of " terra japonica," and this is used only to a limited extent. Bufc as this tanning substance has been the innocent cause of much misapprehension, and has led many novices into grave mistakes, as we pass along we may turn aside occasionally to point out this rock on which many hopes and even fortunes have been wrecked. In illustrating the machinery which is most approved by tanners and workers in leather, it must be understood that only such kinds are here presented as are new, or comparatively so, in construction. Many useful machines are now in use, but so old and familiar that it is not thought expedient to en- cumber these pages with their presentation. Some of the illustrations are of old machines with new attachments ; whenever this occurs an attempt will be made to designate the added novelty, in the text accompanying the drawing, or in the drawing itself. CHAPTER I. SELECTION AND CLASSIFICATION OF HIDES AND SKINS. SIMILABITT OF STOCK AS TO WEIGHT, SUBSTANCE AND CONDITION, HIGHLY IMPORTANT— ASSORTING IN THE SOAK AND HIDE MILL— HIDES SHOULD EE OF EQUAL CONDITION ON ENTERING THE HANDLERS —BREAKL!^G TH3 NERVE IN CALF, KD? AND UPPER LEATHER— IMPOLICY OF WORKING SEVERAL KINDS OF HIDES IN ONE YARD AT THE SAME TIME. To secure the bsst results throughout the tannmg and fin- ishing of leather, there must be equality of condition, and the conditions must be favorable ; anlong these conditions are similarity or equality of stock at the start. Dry flint hides cannot be worked with salted; heavy hides cannot be brought into condition with light ones in the same pack. As far as possible, then, both as to weight, substance and condition, the pack must be in all its respects equal. Some tanners think they effect the same result by assorting their packs after soaking, or after milling or sweating ; but, exer- cising all the judgment that is possible from the outset, there will be opportunity to reject and assort in each stage of the process. Where it is possible the whole lot of hides should be clas- sified before any portion is put into the soaks. This is not always convenient or possible— as, for instance, where the hides are brought from a distant depot, sometimes many miles removed, on the return of teams from dehvering loads of leather sent away. But where it is at all convenient the 18 THE LEATHEE MANTIFACTUKE. heavy hides should be selected and worked in first, enabling the whole lot to come out at the same time. This practice will be found far better than to assort the packs on the last layer, throwing the heavy sides back, and, aside from the consideration of being able to return the whole lot promptly and together, it enables the tanner to give the hides better and more considerate treatment in the soaks, mills and sweats. After classifying all hides of the same weight and general appearance it will be found that some soften much more readily than others. This difference will be discovered gen- .erally in the first miUing. The attendant, standuig by the ■Bide of the mill constantly, with his hand on each side as it 'Comes round in its turn, AviU " draw " (remove) the soft sides. This will leave the hard and unyielding sides in the mill until all the soft ones have been taken out. As a general •experience it will be found inexpedient to " force " these re- maining sides. It is better that they be taken out and re- turned to the soak, and not remilled until a future period, depending on the weather and condition of the water. When tibe weather, is very cold these hard sides may be treated to a bath of moderately warm water — say up to ■80-' of heat— for a few hours. If they are sound they will usually yield on the second milhng. The packs should not be formed to go into the sweats until after they have come from the mill. The experience gained in milling will enable every intelligent man to send iinto the sweats a given number of sides in nearly equal con- dition. From the entrance of the stock into the reception, or hide house, until it gets into the sweats, and, indeed, after it has come from the sweats, the object should be to equahze the sides in the same pack. Especial attention to properly softening is confined almost THE LEATHER MANTIPACTURE. 19 exclusively to the dry flint stock ; both green and dry salted hides soften without effort, and yet it is important that the substance and condition should be the same in each pack, even in this description of hide. Pickled hides should be kept separate from salted, and green salted from freshly taken off hides. If it is important in sole leather hides to maintain uni- formity of condition in the beam house, it is much more so in upper leather hides, kip and calfskins. The wiiter does not hesitate to say that, in the absence of this equality of condition, upper, harness and calfskins cannot be carried through the tanning and finishing processes in a workman- like manner and with good results. This diflSculty may be aptly illustrated by the experience of many small tanners, who cannot wait until they " take in enough stock " of any one description to make a pack ; they feel obliged to make up a pack of hides, kip and calf, some green, some fully dried, and some partially dried or dry salted. The result is that neither class is well worked or prepared ; as they had the misfortune of being joined in the beam house, they go Hnked through the yard, and tho whole pack comes out a tanner's abortion. But even in cases where hides, kips and calfskins are worked separately in the same yard, the tanner often thinks it quite sufficient if he works each class by itself, whereas there are as many conditions to be observed in each class of salted as in dry hides ; not, perhaps, in order to secure a sound re- sult, but much more is required of this class of stock. The grain must be fully preserved, and the whole fiber must be re- duced to a pulp — as it can be, when the nerve is thoroughly broken, and not before. This nerve depends upon many con- ditions for its tenacity. It is easiest broken when fresh from the animal, but may be severed under any ordinary circum- 20 THE LEATHER MANUFACTURE. stances. No calf, hip or upper leather can he made witJi those yielding qualities so highly appreciated in our coimtry ivi/hout the severance of this nerve* and tlie sooner our tanuers ap- preciate this fact tlie sooner will they make leather to take the place of the French and German calfskins that so largely supply our best custom boot and shoe makers at the present time. In all the processes, commencing with the soaking and mill- ing, or wheeling, through the lime and bate, each pelt must be individually treated, and if the conditions are much varied, more judgment and care will be necessary in their treatment as a whole than if they are substantially alike. In the latter case ordinary intelligence would suffice to per- form creditable work ; this degree of intelligence is all that the employer has a right to expect, and hence the im- portance of making as light drafts upon the brain-power of his men as possible, by making the labor uniform on each piece of stock. How few calfskin tanners in this country think it import- ant to classify their skins ! Do they not work all skins from six pounds to twelve in the same pack ? "Whatever is classed as "veal " goes together ; the first selection that is thought of is when the finishers are wanting stock ; the packs are then * So little is known in this country of the process of breaking the nerve, or even of the presence of such nerve, that I venture to add this note, somewhat out of the order in which this subject is treated. When a calf is first killed, this nerve will be seen, by close observation, twitching and contracting on the flesh for a few moments after death ; the whole flesh appears alive with muscular action ; when closely observed, this action will appear to be the result of innumerable interlacing nerves, which a wise Providence has placed there to expand or contract to meet the requirements of the seasons and the varying condition of the animal. When these nerves become quiet and fixed they hold the fiber of the skin, giving it a compact and even rigid feeling. To demonstrate the existence of this nerve, let the following experiment be tried : Take a green skin, throw it over the tanner's beam, and, with a worker, put ten minutes' hard work on the flesh side of one-half of the skin ; the result will be that the half of the skin worked will be distended and soft— even pulpy. Much more would this be the effect if done after soaking thoroughly, as it should be before the usual beam work is done. THE LEATHER MANUFACTURE. 21 assorted and the tanned skins are selected out and sent to the currying shop, while the heavy ones are given another liquor. This is beginning at the wrong end ; the selection should have taken place before the skins entered the beam house, when the advantages of classification would have been secured all the way through the process. In a well regulated calf or kip skin yard, from the time the skins enter the tan- nery they are mated (for reasons hereafter to be stated), and continue this connection through the whole after tanning process. But how can dissimilar sizes and substances be suit- ably paired, and so placed, grain to grain, as to fully cover each other? What has been said thus far goes to the advantage of the intrinsic quahty of the stock ; but suppose some hides or skins are damaged, or partially so ? Those should by no means be allowed to contaminate the good. They are the sick mem- bers, and must be placed in hospital, under observation ; they may not all have the same disease, and must be placed in dif- ferent "wards" or "apartments" for special treatment. When one thinks of the indiscriminate and forcing pro- cesses which valuable stock receives at the hands of many tanners, the inhumanity of the treatment is forced on one's mind. Sick or weE, strong or weak, largo or small, the same methods, the same trying ordeal, must be passed by all, and that so few should break and fail is the wonder. It remains only for me to say a word about the impolicy of working a variety of hides in the same yard. It is not to be denied that some tanners succeed in making good stock out of a variety of hides under treatment at the same time ; but this is the exception, and should not be ventured upon by the average tanner. At least one season's or one year's hides should be of one kind, or as nearly so as possible. Buenos Ayres, Montevideo and Eio Grande are sufficiently alike to 22 THE LEATHEE MANUFACTUEF. be classed together ; Central American and Matamoras, and even diy Texas, are, possibly, similarly conditioned. Califor- nia and "Western may weU be treated as similar hides, requir- ing like treatment ; but there cannot safely be treated dry salted and dry flint hides in the same beam house ; lime and sweat stock cannot go through together without danger, or certainly with hope of the most satisfactory results. The best leather is made by tanners who work a uniform descrip- tion of hide. This is the usual experience, and is based on common sense. CHAPTEE II. PEEPARATION OF HIDES FOR THE BARK— SWEATING. COLD AND WAEM STVEATITSTG — CONSTKUCTION OF SWEAT PITS — CLEANLINESS, LIGHT AND IMPENETRABILITY TO AIE NECESSARY IN COLD SWEAT PITS PROPER CONDITION OE STOCK BEFORE ENTERING THE PITS CARE NEC- ESSARY IN THE SWEATING PROCESS TREATMENT AFTER THE HIDES COME FROM THE PITS- — PART LIMING AND PART SWKiTING GREASE AND SALT ON HIDES. In contradistinction to tlie sweating process of Southern Europe and Great Britain, the American method is called the " cold sweat "; theirs is denominated the " warm sweat." In France, Germany, Austria and Switzerland, perhaps also in other countries of Continental Europe, the tanners sweat their green hides by piling one on top of the other, laid out flat, and covering them up with spent tan or horse ma- nure until decomposition begins. This is their process of pre- paring sole leather hides ; for upper they lime, substantially as we hme our upper stock. In this chapter both the construction and practical opera- tion of the sweat pits will be considered. The modifications and changes of construction in the form of sweat pits for tan- ners have kept pace with the alterations which have been made in the building and location of ice houses for the people at large. The same principles govern both. A good sweat pit would make a good ice house ; possibly a good ice house 2i THE LEATHER MANUFACTURE might not make a good sweat pit — but only for the reason that it would not be sufficiently commodious and controllable. In Great Britain it is customary to " steam sweat " sheep- skins until the wool yields. This is done by inserting steam under a false bottom of a chamber, hung up in which are the skins with wool on. The two methods mentioned may be re- garded as " warm sweating " in contrast with our system of " cold sweating." It may then with truth be claimed that our method of sweating is peculiar to this country. It is now fully demonstrated that a wood, brick or stone structure on the top of the ground can be so completely pro- tected from the rays of the sun and other atmospheric influ- ences as to make a good sweat pit. The ice companies have adopted suiface structures of wood, "filled in" with saw dust, tan bark or charcoal between the outside clapboards and the inside lining of their buildings, and this same form of structure will make a most serviceable tanners' sweat pit. But since the sweat pit is subject to greater changes of at- mosphere than the ice house, it is desirable that the inner lining of the sweat pit should be of a more enduring substance than wood. The damp but warm atmosphere of a tanner's sweat pit decomposes the fiber of the wood very fast — a sound hem- lock plank thus exposed becoming worthless in a few years. On account of this liability to decay, if for no other reason, the sweat pits of tanners should be constructed of stone or brick. But these structures may be wholly above ground, and should be so placed that a wheelbarrow may be run from the floor of the beam house into the main passage way of the sweat pit. These passage ways should be wide — not less than six to eight feet — and so thoroughly lighted, both from top and ends, as to make the passage through them by the workmen both easy and agreeable. The hight of the main passage way should extend above the surrounding pits, and by a THE LEATHEE MANUFACTURE. 25 "lantern" construction of the roof both lipjht and air can be secured in th-e passage ways below. The pits themselves should extend from both sides of the main passage, and be connected with folding doors, wide enough, when fully open, to admit a wheelbarrow. Each of these pits should be large enough to contain one pack of hides, and high enough to admit the hanging of a side doubled, with a space of fully two feet above and one foot below the racks, on which or from which the sides are sus- pended by tenter hooks. The width of the pits should be about eight feet. This will give space for two tiers of sides and a small passage to enable the attendant to make his examinations. Both this passage and the room above and below the hanging sides give opportunity to introduce light and ventilation when required. There is no reason why these pits should not be so light that close observations may be made without the use of a lamp, aud they should always be kept in such cleanly and orderly condition as will permit the foreman or employer to enter and make inspections without fear of soiling their clothes. Too much stress cannot be laid on this feature of our more modern sweat pits. The fact that such inspections are liable to be made at any time keeps a most healthy check on the attendant. The temperature of the sweat pits should be held under control by steam and cold water, with which the main passage should be amply supplied by means of pipes. A properly constructed pit should have a false bottom, under which the steam may be forced, to find its way in condensed spray up through the suspended sides. This process will adequately warm the pit. When too warm, cold water may be thrown from the mouth of a sprinlder over the whole surface, and thus, in a few moments, cool the whole space, and leave a de- 26 THE LEATHER MANUFACTURE. sirable moist atmosphere. Wlien in proper condition the pits Avill stand at a temperature of 60° to 70°, F., with globules of water collected on all parts of the suspended sides, occa- sionally dropping in their condensation from the ends of the hair. Each one of the pits should have at least four lights, 7 by 9 inches, in the end, with a lantern ventilator in the top of the latter, which can be opened and closed by a cord. The f)its should be covered on top by timbers flattened on three sides, and heavy enough to hold up at least two feet of earth. This earth, sodded over and kept well watered, will amply protect the pits from the rays of the sun, and the ammonia which arises fi-om the pits will produce a most luxurious growth of grass, vines or flowers, on this earth covering. The sides of the pits should be protected by a banldng of earth or spent tan. The former is the most desirable, for this earth may be made the means of cultivating grape or other vines with the most artistic and even serviceable effect. With pits thus constructed and under proper control, hides may be properly sweat in from three to seven days — usually in about four or five days. To accomphsh this result the hides or sides must be in proper condition. For the most part only dry flint hides are prepared by the sweating process, in this country, and yet, as we proceed in our inquiry, possibly we may find that sweating in connec- tion with hming may serve a most useful purpose, particularly for green or dry salted foreign hides. The native green salted hides are mainly taken by lime tanners, who find no occasion to use the sweating process. Flint dry hides, or indeed any hides that enter the sweat pit, must first be made absolutely soft in aU their parts — pates as weU as skirts and butts. In this respect banners do not exercise sufficient care. Where the hides are tender (hable THE LEATHEE MANUFACTURE. 27 to break) there is a strong temptation to stop short of this desirable condition. Probably less breaking thus results, but then " old grain " and " hard spots " will come in to offset the breaking. If at any time half prepared, hard sides, should go into the sweats, they should go in with companions equally delicate and tender in their constitution, and all should then be treated alike. The sides should be hung on the racks by tenter hooks, either suspended from the shoulder or from the pate and butt ; whichever way is adopted, the practice should be uni- form, so that a uniform result may be anticipated. As the sweating process advances with greater rapidity in the top than at the bottom of the pit, and as the thicker portions of the hide resist the action of the sweat longer than the thinner portions, it is desirable, as far as practicable, to hang the pates and butts higher than the shoulders and bellies, but as this is difficult to manage, the result is accom- plished by changing the positions of the sides or hides as they advance in the process. Usually, after three or four days, the " assorting out " and changing of position commences, and on the fidelity with which this is done will damage be prevented and a good result secured. No hides, however uniform in character, will sweat exactly alike, and it is for this reason that the careful attention of the employee must be secured. No hour in the whole day should .pass without a visit to the advanced sweats. "When a few sides give indications of " coming " prematurely, before their proper time, they should be dropped to the bottom of the pit, and allowed to lie in piles until their less advanced companions catch up in the process of decomposition. Supposing all the sides to be in the same state of forwercolates through may stand as high as 32° to 36", and then the strength begins to decrease, so that when the bull: of the leach has run off the whole aggregate strength may not be over 14° to 16°. The tanner may stop at any point during this percolating process, and thus secure just as little bulk and just as much strength as he desires. There are many forms of this leach, and as many methods of econom- ically working them. The newly patented form (the Mc- Kenzie patent) now so successfully making extract at Yan- dalia, N. Y., is one which is claimed to be very economical The leaches in this case are round, and only about three feet deep, and are movable. The whole leach, when filled with newly ground bark, is placed under two others of like size. The percolation continues through each until the new 1 )ark is reached. It is claimed that these filled leaches are liandled by machinery so economically that one man, or even a boy, can empty and replace a leach without difficulty. The model indicates great ingenuity and effectiveness, but whether THE LEATHER MANUFACTUEE. 67 tliG saving of labor will overcome the disadvantages of cost must be determined hereafter. The writer once tried a series of experiments on construct- ing leaches that should revolve, and while he had no diffi- culty in perfectly leaching the bark, he very much doubted whether the saving of labor was a sufficient compensation for the cost. The general plan consisted in making a leach eight feet square by two feet deep. This would, when constructed, make an inclosure which would hold one cord of ground bark, weighing about 5,500 pounds when wet, independ- ent of the weight of the leach. This leach was hung by an iron gudgeon firmly screwed to the center of the flat sides or strong timber framework of the leach. On these gudgeons rested and turned this immense box or leach. Two of the ends were perforated full of fine holes, through which w^ater or liquor was run or percolated for a limited time, and then by reversing the leach all the bark which had been packed would be loosened up, and the further percolation could be continued. The final pitching or casting of this leach was effected by opening a large trap door, which would allow all the bark to drop on the floor below, or it could be directed off into the stream by a shute. Six hours of active operation with this leach sufficed to take all the tannin from the bark. One of these small leaches would in twenty-four hours leach four cords of bark, with very Httle labor. But there is considerable machinery and wear and tear to this or •.inj other kind of detached leach, and while they may be suc- cessful theoretically, practically the writer cannot commend llieir use, with his present experience. CHAPTER VII. HANDLING. THE HAND EEEL THE EOCKER HANDLER ITS CONSTRUCTION AND OPERA- TION IMMERSED DRUM WHEELS A METHOD OF RAISING HIDES FROM THE HANDLER VATS THE TUB WHEEL HANDLER HANGING HIDES IN THE HANDLERS— THE " ENGLAND" WHEEL— HANDLING WITH THE COX ROLLERS. Passing by for the present the direct effect of the x^rocess of handhng on the leather, in this chai^ter will be considered merely the manipulation of the stock, wdth reference to the amount of labor required, and the most ' approved methods for doing the best work at the least expense. In no department of the tanners' art is the practice of dif- ferent establishments more varied than in the matter of handhng. Patents and improvements, almost without num- ber, have from time to time been pressed upon the attention of tanners, and the methods of handling are to-day as varied almost as the tanneries are numerous. Commencing with the old plan of "hauling up" by hand, throwing on packs, and allowing the sides to press and drain for a portion of each day— or the still more modern practice of "shifting" over from one vat to another — we have of late years adopted mechanical appHances which make this labor less a drudgery, and less exacting on the muscles of the arms, back and legs. The most generally approved methods are a "hand reel" and the "rocker handler." The hand reel is a THE LEATHER MANUEACTURE. 69 revolving skeleton drum, wliicli is made to turn on the top of a stand or frame elevated about three feet above the top of the vats. Both wheel and frame are light and portable, so that two men can easily remove them from one location to another, over the t ps of the different vats. The reel is placed on the alley- ways between the vats to be shifted, and the sides, hides or skins to be transferred, being tied to- gether, are drawn over from one vat to the other by means of this revolving drum. One man is required to turn the crank and another to adjust the sides or hides in the head vat. By actual count it requires four minutes for two men to perfectly transfer 150 sides from one vat to another, and the labor is made as easy as the old method is fatiguing. Two men will average a pack every eight minutes during the day, including the transfer of the reel. The "rocker" handler consists of a frame set in the top of the vats, constructed of wood. This frame should fill the vat within two inches on the ends, and one inch on tlie sides, so that when it rocks from the center it will play without touching. It should be made of two-inch plank and the frame should be of stuff 2 by 6 inches in substance. The end pieces should be of hard wood, not easily split, since they must bear the strain of the whole pack. The side pieces may be of pine or hemlock, but where hard wood is at hand it is best to use that for the whole frame. The center of the frame rests ou pivots or steps, supported by uprights from the bottom of the vat. A ''stop" at each end of the vat limits the rocker fi'om vibrating up and down more than about eight inches. It is not intended to make any of these suggestions arbitrary as to construction or working, but a little thought at the beginning as to the most durable construction will save m;ic!i repairing in the course of years. The sides are attached alternately by the head and tail to 70 THE LEATHER MANUFACTURF. the cross pieces, backs up and bellies down, by means of hard wood pins, permanently fastened into the head frame pieces. Usually one end is fastened directly to or over the pin, and the other by an adjustable string, which may be not over a foot long, and may, by a permanent slipping noose, be used continuously. [In the illustrations given on subsequent pages will be found good representations of both the "hand reel" and " rocker handler," from which their construction and the manner of operating them will be easily understood.] This "rocker handler" will, also, in the next chapter, be commended over any or all other methods for making plump shoulders and offal, as well as for general economy. Besides these two kinds of handlers now in general use (the latter in the lime and the former in the sweat leather tanneries), the tanners in and around Baltimore, Md., use a lattice drum fully immersed in the liquor ; from the outside or circumference of this wheel or drum the sides are sus- pended, attached alternately by the head and tail. One method is to attach the leather to the outside, but the sides are generally suspended on the inside of the wheel or drum. In the first case the sides are reeled over the outside of the drum, falling in folds, much as the top of an umbrella comes together when put down, and those Avho use this method claim as an advantage that the hquor is pressed out in the process of turning and reeling up on the drum. But, as an objection to both of these plans, it may be said that they elongate the grain transversely, and make thin backs and thick offal. This effect is more noticeable if the leather is fully tanned in this manner, without being taken from the original vat in which it enters. If these immersed drum reels were used only as handlers, as is the case with the rocker, then perhaps the effects spoken of would not be so notice- THE LEATHER MANUFACTUEE. 71 able ; but so observable are these defects now, tliat there in no difficulty in distinguishing leather tanned by this manip- ulation from all others, by the long grain transversely follow- ing the line of the back. The liquors are pressed around to strengthen up the vats into which these revolving drums are used. The principle of the press in the case of these yard vats is not unlike the press of the leach already noticed in Chapter YI. ; indeed, the same practice brings about the same result. Of course no agitation of the liquor is permitted while the press is in progress, otherwise the liquor would mix and destroy the principle of the action. A most economical and efficient method of facilitating the raising and transfer of packs laid away in bark is effected i a the following manner : A light frame made of plank is laid on the top of the Hquor before commencing to lay away a pack. At the outset it floats on the hquor, but gradually sinks as the sides are laid on and "barked away;" when the sides are all in, the framework is at the bottom of the pack. To each corner of this frame should have been perma- nently fastened a half-inch rope as long as the vat is deep. The loose ends of these ropes may float on an attached piece of wood, or may be fastened to the corner of the vat. When the pack is to be raised, the men, standing at each end of the vat with one of these ropes in each hand, together raise the whole pack to the surface, and when so raised they be- lay the ropes around iron bolts or wooden pegs, which are temporarily fastened at the corners of the vat. After they have reached down and removed say eight or ten sides from the top (aU that they could readily reach without the aid of a hook), then they again raise the pack, and so continue until all the sides are thrown upon the pile, or shifted over to the next vat ; but usually it is found convenient to pile the pack 72 THE LEATHER MANUFACTURE. np on the adjoining vat, and lay away in tlie same vat from which the sides were taken. The philosophy of this practice consists in taking advant- age of the law of specific gravity. A side of leather will weigh less ounces under water than pounds out, and hence it is that two men can easily hft a pack while fully immersed in water or hquor, when they could hardly lift ten sides if surrounded by air. This system is more expeditious, is much easier for the men, and withal saves all opportunity for hook marks. Will harness and grain leather manufacturers please take notice of this latter advantage ? There is still another form of handler which, by way of des- ignation, may be called the tub wheel or drum. It was first used at Sparrowbush, N. Y., in 1860, and consists of a large drum fully eight feet in diameter, and the width of the vat. This wheel revolves on a center shaft or flange and gudgeon, resting on the top of the vat. Nearly one half of this wheel is immersed under the liquor of the vat, and the remainder is, of course, out of the hquor. The stock is thrown in at a side trap door, and revolved inside this wheel until colored or ready to go into the layaways. Projecting wooden pins from the inside surface separate and carry around the stock. A more recent improvement on this wheel is to divide it off into four segments or sections, and thus make the compart- ments smaller. It is claimed for this improvement that the wheel turns easier, as a portion of the contents is always held near the center, and only goes to the circumference a portion at a time. Besides, a Swiss calfsldn tanner told the writer that it was within his experience that the large wheel without partitions was too severe on green stock. He was probably right, for such violent action is apt to "purge" stock when it is green and the liquors are weak, as they al- ways must be in the earher process. THE LEATHER MANUFACTURE. 73 The hanging of sides, hides or skins over cross sticks held up by lateral "sapports in the vat, and the agitation of the hquor by plunging, is a most economical method of hand- ling, and one that should be resorted to by all tanners who cannot conveniently adopt the rockers. The " strengthening up" may be effected by drawing off say one-quarter or one- third of the contents of the vat, and replacing by stronger liquor. The gentle agitation of the fiber and the exposure of the full surface of both grain and flesh to the action of liquor is essential to a proper handling process, and so long as this can be effected, no matter whether by manual or mechanical methods, it is all the same in effect. The process which has for so long a time been improperly attributed to Mr. England, and known as the "England wheel" method, has very general acceptance by many light leather tanners. lu this method of handling the wheel re- volves on the top of the vat, and is constructed in skeleton form, with buckets or paddles, which, when turned, dip about six inches in the liquor, causing a thorough and constant agi- tation of the contents of the vat. If the vat is square in the bottom there will be a great agitation, and it wiU answer im- perfectly the purpose, but to make the Hquor and the stock contained in the vat revolve at the same time with the greatest facility, the bottom of the vat should be circular, but not lat- ticed, as was contemplated by the patent of Mr. England. This description of a circular-bottomed vat with a revolving wheel in the top had its origin in the city of Brooklyn about the year 1840 ; but circulating or handUng vats, in a modified form, were well known in Germany long before they were in- troduced here. For the coloring of sheep, calf, kip, hght upper or splits, this wheel and circular-bottomed vat is most serviceable, but when apphed to the after process of tanning, as has been attempted, especiaUy in heavy leathers, must al- 74 THE LEATHER MANUFACTUIIE. ways result in failure, according to tlie experience of the writer. Mechanical power should always be introduced into the handling yard. All the mechanical appliances which have been mentioned are capable of being operated by shafting, pulleys and belting. The "rockers" and "skeleton drums," particularly, should be driven by power, wiiich may be ac- complished by allowing a shaft to run overhead and between each tier of vats. An "eccentric" or "crank" motion can easily be geared from a shaft, as all mechanics understand. The writer has not called attention to several attempts to raise whole packs, both in the handlers and also in the lay- aways, by mechanical power, because they are generally ex- pensive and ineffectual methods of handling. Perhaps this list of handlers would not be complete with- out including the patented rollers of a Mr. Cox, of London, which were brought to this country about the year 1840, and were adopted only in one or, at most, two yards, but, as they were in quite extensive use in some portions of Great Britain, they deserve this mention. The rollers are made of wood, and are covered with cloth or mattmg; two rollers, about two feet in diameter each, are made to revolve with their surfaces so close together as to draw the side through and squeeze out the spent liquor, which, according to the theory of this patentee, has deposited its tannin, and should be dis- placed to give opportunity for new and freshly charged ooze to come in contact with the gelatine of the hide. The sides or butts are tied together in such way as to make a contin- uous belt, and by means of these compressing rollers are drawn from one vat and dropped over into the next. The effect of this frequent compressing of the fiber is to make the leather thin and hard. The writer has seen some very heavy weighing leather made by these rollers, but as the THE LEATHER MANUFACTUEE. 75 system contemplated and used mucli stronger liquor tlian it was usual for our tanners to employ at that time, to tMs cause was attributed tlie wonderful resulting? gain. In tlie first ex- periment with these rollers at one of the tanneries in this country 194 pounds of leather were made from 100 pounds of dry Buenos A3 res hides, but the rollers were so expensive that they have long since gone into disuse here, and meas- urably so in England ; yet it must be confessed that for butts, bends and trimmed leather, it is much better suited than to our sides, and to supply a demand for firm and even hard leather, as is required in Great Britain, these rollers may serve a useful purpose. So long ago as the year 1842 the writer saw at Woburn, Mass., a process of handling upper leather on frames, immersed in the vats, which at that early day presented a foreshadowing of the more modern and better process of rocking the hand- lers. But even yet the stationary sticks or frames are in use by pebble and grain leather tanners in several large tanneries. This successful practice only demonstrates what the writer has re]Deatedly had occasion to say, viz., any method by which the fiber is gently agitated and the whole surface ex- posed to the liquoro will answer the purpose contemplated. CHAPTEK VIII. HANDLING AND PLUMPING. THE USE OF VEGETABLE A^ID MINEEATj ACIDS THE EAELY TJSE OF VITRIOL BY AMERICAN TANNERS CONSIDERATIONS AFFECTING THE AMOUNT WHICH MAY BE USED — -ITS EFFECT ON LIMED AND SWEAT STOCK STRENGTH AND AGE OF LIQUORS TO BE USED IN THE HANDLERS DIF- FERENCES IN THE HANDLING AND PLUMPING OF SOLE AND UPPER LEA- THER. Tlie treatment of sole leather is so different from that of Tipper, harness, etc., in the preliminary or handling process, that the work on these two classes of stock will be consid- ered separately. It has become of late years quite universal to make a dis- tinction between "acid" and "non-acid" treatment in pre- paring hides to be tanned into sole leather. These terms, although in common use, do not convey an accurate idea of the differences in the process. No sole leather is prepared for the yard without the use of acid of some kind, but what is meant by the term "non-acid" is, that only gallic acid coming from bark liquor is used in the one case, and in the other sulphuric acid or vitriol is employed. This employment of vitriol as a means of plumping the fiber of the hide is of quite recent date in this country. In Great Britain the distinction has been maintained for a long time between "vitriol" butts and bends and those that are not raised by this process. As early as 1853 the writer commenced the use of vitriol in the THE LEATHEE MANUFACTUEE. 77 preparation of "union crop" leather. But this was on limed stock, and in very moderate quantities. The mineral acid was used quite as much to counteract and neutralize the lime as to plump the fiber. When used to this limited extent the " buff" was not injured, the grain was plumped, and the whole structure of the hide slightly swelled. But from this small and cautious beginning tbe use of vitriol extended until the sweat leather tanners took it up, and from about 1860 to the present time it has come into general use. If this practice had been intelligently and openly intro- duced, far less damage would have resulted ; but each tanner, dex^endiug upon his own judgment, and, it must be confessed, on very limited information, has gone on blundering, all the time thinking himself much wiser and more skillful than his neighbor, until vitriol-raised leather has come to receive the condemnation of all of our best manufacturers. Certainly it is discredited by all who have regard to the appearance of the bottoms of their boots and shoes. For several years after the first introduction of the new practice the fact of the use of vitriol was kept a secret, and was not exposed until the general quality of our sweat leather had deteriorated to such an extent as to cause alarm. Now the proper use of this acid is better understood, and the earlv abuses in its application are measurably avoided ; but even to this day many otherwise good tannages are injured by the improper use of vitriol in the handlers. In this, as in all other innovations, there should be more frankness among the tanning fraternity ; its members should learn that ignor- ance and bad workmanship reflect finally as much on the in- nocent as on those who are more directly responsible. A tanner who makes poor leather, particularly if the defects are latent and not at once discernible, unfavorably influences the whole trade. 'o THE LEATHEE MANUFACTUEE. The writer would gladly impart sucli information in regard to the proper and permissible use of vitriol as would help t'mners to avoid the defects complained of, but the circum- stances under which this acid is employed are so varied that any general formula or direction for its use would be almost certain to mislead some of those who might wish to be guided thereby. Hides are not all of the same specific nature ; some will bear more acid than others. Thick hides will bear more than thin ones ; steers more than cows ; the butts more than the bellies of the same hide. The consequence is that when our American sweat leather tanners use vitriol on hides worked in without proper classification, and without trim- ming, they are apt to overdo the thin sides or thin portions of the thick ones. There is no way to avoid this difficulty without taking care only to strike the thin portions fairly through and then stop, leaving the butt only partially im- pregnated. In regard to the experience and practice of our sweat lea- ther tanners in the use of vitriol — some color their sides be- fore they introduce them to the acid; others use the acid first and color last, while still others, and probably the majority, use both agents at the same time — they color while they plump — i. €., they use the acid in the coloring handlers, and strengthen up the handler as each new pack goes in, with new, sweet, highly colored liquor and vitriol. How much vitriol may be used with each pack? This question is often asked, but can never be definitely answered without a knowledge of the hides, and of other circum- stances. It must depend upon how much the previous pack has taken up; how strong the acid is; how heavy the sides are ; how fully the leather is allowed to carry o£f the acid, etc. There will be no difficulty experienced if tan- ners will regard vitriol plumping as a tawing process. If they THE LEATHER MANUFACTURE. 79 T;iU cut the thin portions of the sides, and examine in a strong light, they will notice just the extent to which the acid has penetrated ; the progress is as clearly defined, although not quite so plainly marked, as if the tan Hquor itself had been present. Vitriol preserves the hide, and holds, when combined with salt, the gelatine from decay. All the green sheepskin pelts that come from England to this country in casks are pre- served by this process, and may be so held without damage for years. "When these skins come, however, to be tanned, the acid must be neutralized before they go into the liquor, or while in the liquor, otherwise a result is produced just such as we see in much of our acid sole leather. A sheepsldn tanned without neutralizing the acid will swell to more than double its wonted thickness, and will tear as easily as brown paper of the same substance, while the whole structure as- sumes a dark brown hue, which grows darker as it is exposed to the air. From this fact tanners may take a hint, as the writer has done. Indeed, from some early experience in tan- ning what are termed "salted" sheepskins, much of my early knowledge of the use of vitriol was obtained. Vitriol distends and injures the fiber, and if not re- moved from the grain will deposit immediately underneath it a dark brown strata, which is most objectionable to manufac- turers who use buffing wheels instead of hand labor in re- moving the grain on the soles of boots and shoes. In my judgment, vitriol should never be used to raise purely sweat stock. For hides prepared with lime we all know that vitriol to a limited extent may be used without material damage. What, then, is to be done ? All sides as they come from the sweats should be thrown into a lime, and there handled until they fairly begin to feel its effects, say, ordinarily, about six or eight hours. The lime will, in this 80 THE LEATHER MAmjFACTURE. time, sufficiently penetrate the surfaces to neutralize the acid when the sides reach the handlers. Thus treated the dark strata will be either entirely removed, or so far modified as to be less objectionable, depending on the strength of the lime and vitriol used and their relative proportions. It should be remembered that sole leather raised with gallic acid (if the acid be strong) will leave a modified dark strata, but this is controllable by other acids, which the boot and shoe manufacturers employ in " cleaning up their bot- toms." No counteracting agent has yet been found, however, for the vitriol stain, and the exposure to the atmosphere of leather thus affected increases its unsightly appearance. The German-tanned "warm-sweat" sole leather has the difficulty here complained of to a more marked and objection- able extent even than our own tannages ; but as the consumers there care less for the buff than we do, this defect seems to be disregarded. They use vitriol or acid liquors even to a greater degree than we do, and to such an extent indeed that most ot their sweat sole leather will crack and even break by close folding. Consumers of leather in Continental Europe, hav- ing been accustomed to this defect in their own home supply, make less objection to it in us than do the manufacturers of Great Britain. The tanners of Great Britain do not sweat, either by "cold" or "warm" process, and hence they use vitriol and lime jointly, with less damaging effect. It is proper here to say that in France, Germany and Swit- zerland women's sole leather and all the light leathers are limed, as in Great Britain, and this "cracking" and "old hatty" appearance of the fiber is confined to the sweat vitriol and acid raised sole leather, which are greatly inferior to their other tannages. Vitriol-raised leather, when treated in the after process with weak Kquors, produces a most unsatisfactory result. THE LEATHEE MANUFACTURE. 81 Tlie grain is poor, the fiber coarse and hatty. No attempt is here made to solve the mooted question whether vitriol does not destroy the tannin. It is conceded that it will plump and hold the fiber, and will facilitate the tanning, but whether these advantages, in an economical point of view, are not more than overbalanced by its distinctive action on both fiber and the tannin, must be left for future experience to de- termme. In closing the suggestions on this point the writer would like to say that great care should be exercised in handling while in the vitriol vat. If the acid is allowed to settle down on the grain, stains will result which will cause a clouded ap- pearance that will remain to the end of the tanning process. My own judgment is that it will always be serviceable to hang the sides on cross sticks and plunge as the most certain method of distributing the effects of the acid uniformly. In adding vitriol to the pack, be sure to put it in before the sides go in, and plunge thoroughly, otherwise the acid will drop down and discolor the grain. The specific gravity of vitriol being much heavier than that of tan liquor, its tend- ency is to settle, and unless great care is taken it will so settle and mottle the grain of the pack. In preparing hides for sole leather by the lining process, if only so much lime is allowed to permeate the fiber as to enable the tanner to remove the hair, as has been already indicated, distinct bating is unnecessary. If the hide is filled and swelled with lime, the treatment should be such as to remove such excess of lime before the sides come to the handler. But, usually, if the ?;ides are wheeled in warm water for ten or fifteen minutes, they will be sufiiciently cleansed to enter the handler. The first handler liquor should be the oldest and most worthless Hquor in the yard, so worthless that after handling 6 82 THE LEATHER MANUFACTURE. the green pack in it for a few hours it can be run off in the stream or sent again to the back leach.* The pack, after being thus cleansed, so far as this old spent liquor will do so, takes its place in the order of succession in the handlers. If, as is assumed, the rocker system of hand- ling is observed, then it wiU take the place of the pack which has just gone to the layaways, and a Hquor is prepared specially by pumping the strong liquor found in the vat over on the next pack, and so on around until the weakest liquor is placed on the new incoming pack ; care should be observed to feed each pack with an increasingly strong liquor, not, as too many practice, once in each day, but at least twice. Far more damage is done by feeding too slow than too fast ; so long as the old liquors from the layaways are used there need be no fear of either feeding the packs too fast or too frequently, only let them be fed in their order of entrance. Of course, as many packs should go out as come into the handlers daily. It will be found profitable to keep each pack from ten to twelve days in the handling rockers, or in any other method of handling that may be adopted. This time will suffice to overcome all the effects of the hme, fairly plump the sides, and set them well on their way toward the after tanning process. As a last parting word on this subject the writer would urge tanners to put away from their minds the fear so often ex- pressed that liquors may be too strong to start with. If eight or ten packs are in the handlers, commencing with the head * Just here the writer would say that, whether this old liquor should go again to the back leach or off in the stream will depDnd very much on the manner of using the liquors. If, as in the true system of using the press leach, no liquor is allowed to go back iintil expended, then the dirty water (for it is little more), without acid or tannin, which washes an 1 cleanses each new pack which comes to the han Hers, should be discarded ; but if there should remain either gallic acid or tannin in the liquor, then it should cei'tainly go to the back leach. Without exer- cising some discretion in this regai'd valuable qualities may be thrown away. THE LEATHEE MANUFACTURE. 83 pack and running down to tlie last one, the best and strong- est of the discarded layaway liquors may be used with safety. These liquors will always contain acid enough to prevent the "puckering" or " binding" of the grain. Liquors weighing by the barkometer 16° are none too strong for the head handler. So large a proportion of this weight will be acid that they may safely be trusted to work no harm. The treatment of the lighter tannages, such as upper and harness leather, in the handlers, is far different from that of the heavy sole leather tannage, just considered. These lea- thers are sold by the side or foot, or should be, as no tanner can afford to treat his stock as such goods should be treated, and then sell it by weight. After the Hme has been thoroughly removed by a bate of hen manure, or wheat bran, or some other depleting process, the stock enters the handler, in the first instance just as tha sole leather did, but instead of taking a course of old, sour, strong liquors, it is only retained long enough in the acid liquors to "brighten" and clear the grain, and then weak, sweet liquors should be fed to the packs, just in the order in which they come from the leaches. These liquors should go back to the leaches very frequently, to be " sweetened " and " strengthened " up. Fresh sweet liquors standing from 10° to 12° should be as strong as is ever permitted in the handlers. The " rockers " should be used, however, to plump and handle even upper, harness and calf, for, although the sweet liquor wiU prevent that extreme plumpness so desir- able in the heavier tannages, a close, round grain will be formed, and a degree of fineness and plumpness of the shoulders and offal will be secured not attainable by the usual manual handling process. CHAPTER IX. LAYING AWAY. TIME EEQTJIBED AND STRENGTH OF LIQUOR WHICH SHOULD BE EMPLOYED TANNIiSTG IN THE HANDLERS VS. LAYING AWAY EUROPEAN METHODS " BLACK EOT " AND WHITE SPOTS THEIR CAUSES AND THE REMEDIES SHOULD HIDES BE LAID AWAY GRAIN UP OR FLESH UP ? MAKING WEIGHT IN THE LAST LAYER. Proceeding in the order of tlie successive processes of tan- ning, we find our pack coming from the handlers not only well " plumped" and uniformly "colored," but fairly "leath- ered." The stock has taken upon itself " substance," and a reasonable degree of firmness. Supposing that four layers will now carry out our tanning and completely fill the fiber, we shall assume that the remaining work will be divided into the following periods of time, during which four successive layers of bark will be given each pack. To the first layer we will give ten days, to the second fifteen days, to the third twenty days, and to the fourth thirty days, making in all seventy-five days. But it must be evident that leather differ- ing in substance and weight will considerably vary in its requirement of time ; and then, too, much will depend upon the season of the year, the strength of Uquors applied, and other circumstances. If we commence with a Hquor of 16° degrees strength with the first layer, and end vdth 30° on the fourth layer, seventy-five days will be found ample time to tan the heaviest sole leather. The writer tried an experiment on one pack of slaughtei THE LEATHER MANUFACTURE. 85 hides, to test the actual time necessary to tan good middle and' overweight leather, averaging say 20 pounds per side. This experiment, made under his own daily observation, enables him to speak with great confidence of the result. The hides were bought of the Butchers' Association of the City of New York, and weighed 70 pounds each, trimmed and cured. On 3 week was consumed in their preparation for the bark. They were colored and handled for three days in an old sour liquor from the first layers, when they were put into a liquor of 20 degrees strength and handled daily, "shifting" from one vat to another each day, and receiving just enough added strength to keep the liquor at 20 degrees. At no time was the liquor over 22 degrees or under 18 degrees. In sixty-one days from the time the sides came Ijfco the hand- lers they were taken out not only fairly " struck," but well tanned. The color was "fairly good," although not as bright as other packs which hadlDeen laid away in the usual manner, and had taken fifteen to twenty days more time. The con- chisions drawn from that experiment were as follows : 1. Well cured New York City hides will make 65 pounds of leather for every 100 pounds of green cured and trimmed hides. 2. Sixty days in the actual process of tanning, handling once each day in suitable liquors, will tan the ordinary middle and overweights sole leather. 3. About one-third more time is required if the leather is tanned by being laid away in the usual manner. 4. The color is both lighter and more uniform when laid away than when handled. Besides, the tendency of the sides to bag is far less when tanned in the usual way, by laying away in bark. This experiment, if read by a German, Swiss, French or Austrian tanner, will be regarded as extraordinary, but an 86 • THE LEATHER MANUFACTURE. account of it is given here, not because it is exceptional in this country — for many better results have been attained— l3ut for the purpose of bringing into contrast our methods of tanning as compared with those of the Continent of Europe, for in all statements affecting results the witer must be understood as drawing a clear distinction between the pro- cesses in Great Britain and those of the Continent. It is not claimed that these results are practically secured in all instances, or even in a majority of cases in this coun- try, for the causes of detention which go to make the aver- age time and results are but too well known. These causes of delay will be considered in their appropriate place, but theoretically our system accomplishes all that is here claimed. As possibly these statements may be read by tanners over the sea, for their information, as well as for the instruction of our own tanners, it may be said that our universal custom of leaching new bark and using the decoction obtained for our tanning agent, is not practiced to any extent by tanners in Continental Europe. They color their green packs in hand- lers made from the old sour liquors, which are pumped from the layaways, adding (as is the custom of some) a few bas- kets of "spruce" bark. The hides, in small yards that are run without power, are "poled" in the vat every hour, and onoe or twice each day the stock is handled up. But while yet quite "green" and "pulpy" the packs are laid away in outdoor round tubs or vats, from eight to twelve feet deep, and from six to ten feet in diameter. The first layer is made of old, partially-spent tan, laid fully one inch thick on either side of a hid^ or skin, and well stamped down. When the vat is finally filled with these alternate layers of bark and green pelts, water is run in to fill the interstices. The acid of the bark preserves the gelatine, and at the same time neutralizes any lime which may have THE LEATHER MANUFACTURE. 87 been left from the liandlers. After twenty or thirty clays' time this stock is raised, the bark " skimmed out," and the pack relaid. To the old a portion of new bark is added, and at each subsequent "shift" or "turn" of the pack more new bark is added, all the time holding the old acid liquor which has accumulated. The writer was informed that in most instances from sixteen to twenty months are occupied in these layers before the leather is finally declared tanned, and the statement may be fully credited, for in no instance, among the numerous tanneries visited, did he see any attempt to leach new bark ; such leaching as was attempted was confined to the old, spent bark, that had been literally worn out by frequent handling. This process is sliohtly varied with calf and upper in the handlers and layaways, but substantially the same system is followed out in all their tanning. Perhaps, in justice to a few large calfskin tanners — notably so in the case of M. Mercier, at Lausanne, Switzerland— it should be said that much more vigor and a greatly improved system was em- ployed. This will be more fully mentioned in the chapters on calfskin tannages, in another place. The writer hesitates to state the methods employed in Great Britain, for the tanning agents there used are so en- tirely different from our own that comparisons are impossible, and might, if given, be misunderstood. They use decoctions quite as strong, in fact, as we do, and much stronger, meas- ured by the test of the barkometer, while the time in which they tan is very nearly or quite equal to that made by our best tanners. If they take longer (as many of them do), as much even as ten m-mths, it is on heavy South American hides, made into butts and bends that are very stout in sub- stance and extremely fine in texture. But native sole leather hides, also upper and kip leather, from both native and foreign 88 THE LEATHER MANUFACTUEE. liides, are "put through" quite within our best time, and in the most artistic way. American tanners can learn much from the economies practiced and results produced by the tanners of Great Britain, for they do manage to make ex- ceedmgly good leather from very small quantities of tan- ning material, whether native or foreign. To return from this necessary digression our methods of laying away will now be given with more minuteness. More than forty years has passed since the " kiffmg " away process was given up, and leaching and bark liquors introduced in its >stead. Few men are old enough to remember when at Salem, Danvers and Cummington, Mass., water was used instead of liquor in the layaways for sole leather tanning. At present, the bark liquor used in the layaways is depended upon to do the tanning, and not the interlying bark at all. The general usage now is to run the strongest and newest liquor direct from the leaches upon the head packs of the last layer. These liquors should weigh by the barkometer fully 30 degrees of strength. After 30 days' use they will be reduced to 24 degrees, A portion of this indicated strength is acid. Twenty days' further use on the third layer will reduce the strength to 18 degrees, and thus down step by stejj until a large portion of the strength will be acid and not tannin, when the liquors will be put on the first layaways, or may be run into the handlers and fully exhausted. This is not, it is true, an invariable custom, for too few of our tanners have anything that may be called uniform methods, but the general leaching of bark and the use of the graded decoction on the packs, in the order of their coming in and going out of the yard, must be conceded to be our com- mon practice, and to this extent the system is exclusively American and English. The manner of running liquors from the leaches to the yard \ THE LEATHER MANUFACTURE. 89 is by covered, inclosed wooden tubes or bored-out logs, either under ground or under covered ways. The method of con- struction and cost of these will be stated hereafter, but where heat is used on the head leach, these liquors are too often sent into the yard warm, or even hot, and when thus used, very much injury to both color and buff is the result. Yet, as Ihese head or strong liquors are, or should be, confined to the head or nearly tanned packs, positive damage to the gel- alme of the hide does not follow to the extent which would be supposed ; while if these warm liquors, from mistake or ignorance, go to the half-tanned or green packs, "black rot" is almost sure to result, particularly in the summer season. The damage is caused by the decay of the animal fiber— ac- tual decomposition of the untanned or raw hide. The ex- ternal appearance of this damage appears as a sinking in of the two surfaces, caused by a general disturbance of the cen- tral tissues. Wlien the decomposition proceeds still further, and the surfaces break, partially tanned "puss" exudes. This disturbance and damage has been popularly denomina- ted the " black rot," because, upon the grain side, in addition to the " falling away " appearance spoken of, the surface turns black, showing dark or black spots wherever this damage oc- curs, and this is generally in the thickest and best portion of the hide. While on this subject of latent defects and damage, perhaps it is as well to state the experience of our tanners in regard to the "white spots," of which there has been so much reason to complain, and which, even w^th our conceded ability to remedy, still cause great dnpreciation of value in much of our sole leather. This defect occurs from imperfect beam work. In the sweating process the hides are soaked, milled and sweated within a week, and when the atmosphere of the sweats and the nature of the hides favor, the hair " comes" 90 THE LEATHEE MANUFACTUEE. quite freely; as that fact, under our process, indicates tliat all lias been done that is necessary, the stock is turned into the liquor, when, in fact, the workman has never touched much of the grain surface of the hide, thus leaving mucus and grease. Often the grain has been saturated with the greasy substances of the animal, which are not overcome or worked off by the beam hand, but remain to resist the action of the liquor. Some tanners call this " mucus," but the greasy substance which causes this white spot is different from mucus, as will be demonstrated by a little examination. The New York leather trade, several years ago, offered a reward to any tanner who would discover a remedy for this defect, and a Mr, Edson came forward with a solution of the difficulty. He discovered that potash, soda ash, or any strong alkali, applied to this untanned or uncolored white spot, would at once make the grain take the coloring matter, and subsequently receive the tannin. This was a perfect remedy, and led, as any one may perceive, to the cause of the trouble. "Whereas other tanners ascertained that rubbing CD the surface with pumice stone or brick, or scraping thoroughly with a knife, would measurably relieve the damage, the real cause of the difficulty was not suggested until the alkali test was applied, and then we all comprehended that grease, in some form, was the source of the trouble, and, therefore, to Mr. Edson was awarded the valuable consideration offered by the trade. If, therefore, hereafter, any tanner suffers from the appearance of these white spots, and does not apply the remedy, he has only himself to blame. These spots may be avoided in two ways : First, by thorough working on the beam ; or, second, by the use of a strong alkali on the spots affected, after the sides have been colored, and the defect complained of discovered in the handler. The best practical method to overcome these spots would, THE LEATHER MANUFACTUEE. 91 perhaps, be for tlie tanner to liave a carboy standing in Lis yard with either a strong decoction of sal soda or soda ash, from which the attendant on the handlers can take a small portion, and by the use of a rag or sponge touch, and even slightly rub, the affected part. It will cause a dark or even black stain at first, but this will finally disappear in the after process. Some tanners prefer to throw the sides affected on a table or beam, and rub or scrape the spots with a smooth steel edge ; a round pointed Imife is serviceable for this pur- purpos-^'. The latter course can only be pursued, however, when the spots are small and infrequent. My judgment is that where sufficient care is taken to work fully over the grain in the bsam house these spots will not be encountered in the handlers. It is probable that if hard wood ashes, soda ash, or sal soda, were freely used in the soaks of such hides as usually give this trouble (as, for instance, dry Western and Califor- nia), no white spots would ever make their appearance in the handles; besides, the greasy hides would soak more uni- formly. Y/hen a pack of dry hides is thrown into soak in- discriminately great injustice is done the " sun dried" and greasy portions, from their more persistent resistance of the soak. The question has often been raised whether the sides should be laid grain or flesh up in the layaways. The prac- tice is to lay grain up, and this is justified on the ground that, in "hooking up," the grain is not so likely to be scratched and marked as it would be if the sides were laid flesh up. If, as seems quite likely, the color is seriously affected (par- ticularly in hemlock tannages) by the settling of the coloring matter on the grain, and a deeper, darker red is the result, then tanners may well inquire whether, in their attempt to avoid hook marks, they do not entail upon their stock a worse THE LEATHEE MANUFACTURE. evil. Besides, it may be asked in this connection wlietlier it is not probable that tannin will enter the fiber of the hide more naturally from the flesh than from the grain surface. The pores of the hide, when on the animal, certainly do open their valves outward from the flesh, for all the emanations of the animal body go through these outward opening valves or pores of the skin, which never receive back from the grain to the flesh. We all know that the goat and sheep skin tanners, when they "sew up" their skins, keep the grain outward, and tan altogether by pressure from within. But some one may ask. Does not the tan hquor surround both surfaces, and seek admittance equally from each side? This may be answered in the negative, for the heavier or stronger liquor settles, and when the sides lie upon each other in layers, both the strength and the coloring matter tend to settle downward. The theory is that when the tannin comes into contact with the gelatioe of the hide the union is made instantly, and then, if both the hide and tannin are allowed to stand in perfect quiescence, the conclusion is drawn that not only does the strong hquor settle, but it does its work instantaneously, from underneath, while from the top of the side this specific- gravity principle of the Hquor keeps on acting for a consid- erable time, forcing downward the renewed strong liquor, and bringing itself into contact with the untanned fiber. This may be refining on speculative ideas, but such a theory does prevail among some. One of these theorizing tanners, within the knowledge of the writer, always acted upon this idea, and made it his habit, several times each day, to walk over his layaway packs, stopping to press his weight forcibly on each as he passed. He always insisted that by this course he displaced and dis- turbed the fixed relation of the liquor to the gelatine of the hide, and brought new tannin in contact with the hide. This THE LEATHER MANUFACTURE. 93 we know, tliat agitation of the fiber and frequent replacement of tannin does facilitate the process. The last or fourth layer is purposely prolonged, not only to fill the fiber and make the leather firm, but also to bright- en the color, as is sure to result from the acid liquoi-, which a-X'umulates with age. The fiber is fairly tanned on the third layer, but the filling process — the extra weight, indeed — is made on this layer, and the tanner who fails to give ample time to this last layer must be content with inferior solidity and gains. Can leather be overtanned? Yes. It may be so thoroughly tanned as to leave no grain to buff, and really no life or elasticity to the fiber. CHAPTEE X. DEYING AND FINISHING. WASHING AND SCKUBBINa THE LEATHEK THE " HOWAED SCETJBBEE "• — WHEEL OR DRUM SCRUBBING DRAINING HOW THE ADMISSION OF LIGHT AND AIR SHOULD BE REGULATED IN DRYING DAMPENING BEFORE ROLLING THE FIRST AND SECOND ROLLING EFFECT OF THE ROLLING ON THE BUFFING QUALITIES BLEACHING WITH SUGAR OF LEAD AND SULPHURIC ACID THE WARM SUMAC BATH EFFECT OF THE LATTER ON CALFSKINS, GRAIN LEATHER, ETC. From tlie last layer in tlie yard the finisliing process begins. If mistakes have been made and defects are apparent it be- comes the duty of the finisher to consider and overcome them. Wliere a uniform system prevails, both in the beam house and yard, such defects should not be of frequent occurrence ; but whatever they are, and. wherever they occur, it is the duty of those who have charge of the drying and finishing loft to make amends, as far as possible. The first duty of the finisher is to cleanse the leather from aU sediment and extraneous matter. This can be better begun before the leather has been exposed to the air than after such exposure. For this reason the pack should te taken in hand immediately on coming from the layer, when the leather should be thrown into clean water, or may, if there are stains and a mottled condition of the grain, be thrown into an old sour liquor, and left for a day or more. We must bear in mind the object to be attained, namely, to cleanse and THE LEATHEE MANTJEACTURE. 95 purify the grain and flesh. This can be done in various ways — first, by rinsing and hand scrubbing ; second, by re- volving drum wheels, with surfaces covered with splint brooms. This method is covered by the patent of Mr. Howard, and the scrubbers are known as the "Howard scrubbers." The third plan is by a revolving drum wheel, during the revo- lutions of which the leather is washed by a constant tumb- ling and turning over in water, which is freely supplied. This wheel, in its applicaffon to such service, is also covered by a patent. The merits of each of these processes will be considered in their order, but before presenting the remedy for the evils which necessitate this scouring let me consider their cause. If the liquors are obtained from the press leach there will be no sediment or discoloration to remove, and consequently nothing more will be required than rinsing and scrubbing with a hand broom, or brush. But if the liquors have come from the "sprinkler leach," or from the ordinary "flooding leach," then there will have accumulated bark dust and sed- iment, blended with resinous matter, which Avill attach itself to the flesh and grain, and will require mechanical power for its removal. The " Howard scrubber " is now largely reHed upon to re- move these defects. It consists of two revolving rollers or drums, with their surfaces coming very near together, to which are attached brooms or brushes, which quite meet. Through these scrubbing surfaces the sides are made to pass — sometimes once, but often twice and three times. The friction is increased by holding back the side with the hand with more or less firmness. Two men can, with this machine, pass thr ough about 500 sides per day, and do the work well. More recently the "wheel " or " drum scrubber " has come into use. This consists of a drum wheel about six to eight 96 THE LEATHER MANUFACTURE. feet in diameter, four or five feet wide, made strong enougli to resist tlie hammering process of the revolving sides of tanned leather, which are made to " thrash " around in the inner surface of the wheel as it revolves slowl}^, say about twenty revolutions per minute. The inner surface of this wheel is furnished with pins or projections, which carry the sides around with the motion until they are raised sufficiently from the bottom to violently agitate the fiber by their drop- ping down, and by the friction caused by the sides rubbing against each other the surfaces are cleansed, very much on the same principle as iron castings are now made smooth by being rubbed against each other in a reA^olving wheel — or as shoemakers' pegs are polished by friction and cont;ict — being revolved in bulk insi'ie a tank or hogshead. It is claimed that the most of the bark sediment or accumulation is re- moved by this wheel within five minutes, and as about ten or fifteen sides can be thrown in at a time, it will be perceived that the cleansing process is rapid and economical. Great care, it appears to me, should be observed lest this wheeHng be continued too long, the effect of which would be to pound out the weight and make the leather soft. The writer is assured that with care these defects can be avoided. When the sides have been thoroughly cleansed, by means of either of the foregoing processes, they are usually laid in packs to drain, but in doing this great care should be taken to place flesh to flesh and grain to grain, with each side so exactly covering the other as not to allow the flesh of one to touch the grain of another. Unless this precaution is taken the strong liquor, which is absorbed and held by the flesh in undue proportion, in spite of all attempts to remove it. will impart itself to the grain of the side it comes in contact with, if the pack is unevenly spread, so that the drainings can run down and stand in small pools on the grain surface. Such THE LEATHER MANUFACTURE. 97 spots will be marked with the stain of the bark liquor when the leather is finished. The most ready way to avoid the forming of these " cups " is to throw the pack over a " half log," cut lengthwise, whi.-h is made as follows : Saw a hemlock log, two feet in diameter, through the center ; turn the concave surface up and the flat surface on the floor, and lay the pack lengthwise on this stick of timber ; it will be almost impossible in this way, with or- dinary care, to have any cavities form into which the spent liquor will run and cause these stains. The pack, while thus exposed to the air, should be covered with canvas, to prevent the edges and exposed surfaces from meeting the hght and air ; otherwise such portions will be - come darkened to such an extent as to show finally great discoloration. After the pack has been thoroughly drained, a slight coat of fish oil should be put on the grain and flesh by a rag, and the leather may then be hung up to dry. If the Turret dryer is used, or the principle of that dryer is observed in the con- struction of the building in which the leather is placed, the perfect control of the light and air thus obtained will enable the workman to keep all light and any considerable drafts of air from the leather for three or four days, or until the sides are fairly stiff and dry on the surfaces. After the moisture has been evaporated from the surfaces air may be admitted, but not a strong light, for the free admission of light to the leather is certain to darken the color. Ten days will dry the heaviest sole leather if a proper drying loft is employed, but, whatever time is requisite, the leather in all its parts should be thoroughly dry before it is taken do^\Ti. When in this condition it may be held subject to the call of the roller. Two days at least before the leather is rolled, the " damp- ening process" should begin. The sides should be first 7 98 THE LEATHER MANUFACTUEE. sprintled with water carefully, both on grain and flesh, and then laid down, grain to grain, and flesh to flesh, taking care as before not to have " cups " form where liquor stains may occur. After a period of a few hours the same process may be repeated, but with more care, making certahi this time that all parts have not only been reached, but that no more water has been apphed than wiH readily absorb. The pack should then be carefully laid in a large wooden box or tight room, care being taken to pack snugly, so as to get in as many sides as possible, and at the same time to prevent the air reaching the skirts to dry and discolor them. If the dampening process has been attended to with care, the leather will be in condition to "pack" under the roller without "rebounding" or " comingback;" but to make sure that all the parts are evenly moistened, great care should be taken by the attendant to re-sponge both grain and flesh hghtly before the sides are passed to the roller, taking special pains to retouch such spots as have lost their moisture, and become partially dried. It will also serve a useful purpose to pass an oiled rag or sponge over the grain surface, to prevent "furring up" under the roller and on the roller bed. The leather should be so prepared that the whole fiber will pack sohd, without being so damp as to induce the soluble portion of the coloring matter to press through the grain, as will be the case if the leather is rolled when too damp. We all know that snow may be too dry as well as too damp to pack, and the same is true of leather. The happy medium should always be observed to secure the best result. Since our tanners have been trying to meet the tastes and wants of the German market, some of them have adopted a somewhat different method in finishing vitriol raised leather. Only the grain is dampened, and the residue of the fiber h rolled dry, or nearly so. This process gives a fictitious sub- THE LEATHEE MANUFACTURE. 99 Ktance, and a harsli, hard, dry fiber, whicli seems to corre- spond to the character of the German tannages, but cannot permanently meet the wants of either American or Enghsh manufacturers. x4.ll sole leather should have the stretch taken out of it so completely that when the sole is cut by machinery there will be no waste, as it goes on the bottom. It should exactly fit, without any paring or loss. Leather may be too hard as well as too soft, but it cannot be too solid. Keeping in view the distinction between " hard" and " solid," the reader will understand that solid leather is a Avell-packed fiber, whicli cuts " cheesy" and " smooth," and not dry and " husky," as much of the vitriol raised leather cuts, increasing in these undesirable qualities with age. The leather is rolled for the first time in the moist' ("sam- raied ") condition previously described. The grain is fairly flattened and made smooth; the whole fiber is firmly packed; but there remain roller marks on the grain, and defects which must be overcome. How shall this be done ? Some will say — ^let the leather be fully dried and then brought back and rolled on the flesh side, grain side to the roller bed, and this will remove all marks on the grain from the first rolling, and will, besides, leave a gloss and finish oa the grain which is mnst desirable. Much can be said in favor of this style of finish, and, perhaps, no one has been more influential in in- troducing it than the writer. But for all that, it is not the most artistic or desirable. It will do on hemlock leather, where mere color in the buff is sought, but where both "color" and a " velvety " buff is desirable, i.e., where the bottom, after being buffed, is to present a " soft nap," and at the pame time a Hvely and beautiful flesh color, then some other process must be adopted. Tiiis other and better pro- cess is a second rolling, immediately or very soon after the 100 THE LEATHER MANUFACTURE. first. The sides, after the first rolling, may be spread al30ut tlie loft, and within an hour after the first rolling the second rolling should take place from the flesh side, as the first was from the grain. It may even be of service to slightly re- dampen the grain in spots, if the leather is allowed to re- mam as much as an hour in a dry atmosphere between the first and second rolhng. The care required to finish " union crop " leather, as well as pure oak, is incomparably greater than is usually be- stowed on the ordinary hemlock, and yet the time is prob- ably not far distant when the same care will fully compen- sate the tanner in the latter as in the former tannage, par- ticularly where slaughter hides are used. Some of our union leather tanners are now turning their attention to pure hem- lock tannage, and their greater success in producing hemlock leather justifies the impression that more care in the finish of slaughter hemlock will well repay the tannner. One con- tinent has come to be well nigh convinced that hemlock bark is as serviceable in tanning as oak, and it is quite within the range of possibilities that another decade of years will bring the whole Eastern World to this conviction. The branch of the finishing business which may be called the bleaching process might profitably occupy a chapter by itself, but as the writer does not pretend to fully understand and, if he did, would not commend the various devices of bleaching leather by sugar of lead and sulphuric acid, which is the most common practice in general use among fair lea- ther manufacturers— the suggestions on this subject will be compressed in this chapter. The practice now is to dip the sides alternately, first into a bath of sugar of lead, and then into one of sulphuric acid, until the coloring matter of the hemlock is fully removed. This bleaching process produces an immediate effect that is almost magical, but when the THE LEATHEH MANUFACTURE. 101 finislied leather is exposed to the air and light for any con- siderable time the dehcate pink and cream color turns to a " murky brown," and the finish is in all respects most objec- tionable. The only natural and honest bleaching process known to the writer is that of " sumac baths." After the hemlock sides have been cleansed of all extraneous matter, as before described, by the most effective mechanical device known, it must then be hung in a vat of warm sumac liquor, and plunged frequently for one day (and even a few hours will sensibly affect the color). Usually one bag of Yirginia sumac will suffice for a pack of one hundred sides. This pro- cess will cost about five dollars for a pack, or five cents per side, weighing fifteeen to twenty pounds. The sumac liquor forms a vegetable acid, which acts most kindly on the grain of hemlock slaughter leather, not only removing (neutraliz- ing) the color, but softening the grain, and contiibutes very much' to the whiteness and clearness of the buff. Hemlock leather thus bleached will retain its improved color for a long time, and never go back to that muddy and objectionable color so common where other bleaching processes are em- ployed. As it is the acid that effects the object sought, the sumac liquor should be retained long after its tannin has de- parted. As a mere tannin agent it is only valuable, as all goat and sheep skin tanners comprehend, while it is fresh, before the acid forms ; but for the purpose of bleaching hem- lock leather, it is questionable whether the old cast off sumac of the morocco dresser is not quite as valuable as new sumac. At all events, some experiments that have been tried go to this extent in their conclusions. Slaughter hemdock leather, tanned with liquors of moder- ate strength, say 16 to 20 degrees, from the press leach, will come out with a color that is between the lemon and the orange ; if to this Ave add the warm sumac process, we get 102 THE LEATHER MANUFACTURE. a color so nearly a light lemon or a flesh color as lo meet the requirements sought in the best oak leather. Indeed, for all fine work, whether men's or women's, the buff is superior to that of most pure oak tannages, for these have a " sickly white" which soils much more readily on the bottom than the flesh color of the hemlock or union tannages bleached as here indicated. This bleachiog process is particularly serviceable on calf, and all grain finished leathers, including harness and bridle. No purely hemlock tannage will " take the blacking " so well as leather which has undergone this treatment. With it, hem- lock grain leather can be made to hold its color almost equal to that of pure oak tannage. Calfskins properly tanned in hemlock can, by this bath of warm sumac liquor, be made equal in color to the best French, German or Swiss ; indeed, the resemblance is much greater than that of skins tanned by pure oak tannage, for the French color is controlled by the "larch " bark, the equivalent of our " spruce," which, as all know, is a modified hemlock in color. Above all these cou- siderations actual experiments seem to indicate that this su- mac process will add enough to the weight to pay for its cost. However this may be, it will add greatly to the intrinsic qual- ities of all upper stock and much to the beauty of the buff in sole leather. As directly connected with this subject, it may be men- tioned that for many years the union crop leather tanners used " sour milk " to wash the grain between the first and second rolling. This treatment not only " lightened up " the whole complexion, but removed clouded spots and ..even stains, and was withal a most harmless bleaching process, as the light and air did not affect unfavorably the buff, any more than in any of the vegetable processes. But mineral acids are objectionable and should be avoided. CHAPTER XI. THE CAUSES WHICH AFFECT COLOR AND ASSIST IN THE MAKING OF A VALUABLE EMBOSSING GRAIN. WHY LEATHER SHOULD BE THOROUGHLY DRIED STRUCTURE OE THE GRAIN IMPORTANCE OP A PERFECT FINISH CARE TO BE TAKEN TO AVOID STAINS AND DISCOLORATION " CUIR " COLOR THE NATURAL HEMLOCK COLOR " RUSSIA LEATHER " COLOR FRAUDS IN SELLING HEMLOCK FOR OAK LEATHER DURING THE WAR COLORING TO BE DONE IN THE HANDLERS EFFECT OF " STRIKING " THE GRAIN. In the preceding chapter it has been insisted upon that leather should be thoroughly dried before being taken down to roll. The importance of great care in this matter may not be appreciated without some further attention to the pe- culiar nature of the " grain " and an examination of the causes wdiich affect its structure, including its color and its embossing qualities. Some tanners, defending their practice, Fay, " Why occupy so much time in thoroughly drying the fiber of the leather, and then immediately thereafter dampen- ing down again ?" At the expense of seeming over nice, the waiter will explain the reasons for taking this course. The immediate outside grain of leather is a thin tissue, hardly thicker than thin paper. Next to this is an inner grain, several times thicker than the first, and very much more spongy in its nature. Together these two structures are usually called " the grain," and for the purposes of thiS: discussion may be treated as one. 104 THE LEATHEK MANUFACTUEE. Much of the value of sole, harness, trunk and other leathers depends upon the appearance and condition of this grain. Upon this outer surface the harness maker and saddler stamp their forms and make their ornaments ; the currier and fin- isher stamps or presses the grain with dies, making imitation hog, goat or seal skins out of ordinary neats leather. The lioot and shoe manufacturer first buffs, then stamps and otherwise embellishes the bottom of his ladies' and gentle- men's fine work, on this grain, and the manufacturers of the fin3r leather fabrics emboss this surface with the most artis- tic forms. To enable these impressions to be made with proper effect and remain lasting — retaining permanently both form and color — the grain must be " clear," " bright " and "perfect" as to color, and "mellow," "elastic" and yet " firm " in structure. This, then, is the nature of the surface or grain which is to be kept bright, and from which all coloring matter must have been wa hed and cleansed as far as possible by previous manipulation. If any device could be employed to pack the main fiber of the sole leather, and at the same time leave the grain perfectly smooth, it would be most desirable not to pack or compress this grain at all, but leave it soft and im- pressible for the artisan who comes after the tanner ; but in- asmuch as the inner fiber cannot be compressed by any ' known means without also compressing the grain, the next ) 1)est thing to do is to so manage as to leave this grain as soft, elastic and compressible, and also as free from coloring mat- 'ter as possible. It is found by experience that the coloring matter of the bark, when in a soluble condition in the fiber, will spread, \vhen compressed, almost as readily as ink on paper, and for this reason, after washing and cleansing the grain, it is found '.desirable to fasten the coloring matter in the fiber by evap- THE LEATHER MANUFACTURE. 105 orating all the water, which will leave the coloring matter in a dry, insoluble and fixed condition. This condition must not be disturbed— certainly not to the extent of making it soluble, by any after process of wetting- ; if that is done, the pressure of the roller will bring the coloring matter to the surface, and nulhfy all the advantages gained by the original washing and scrubbing, for the grain is almost as porous and as susceptible of receiving stain as blotting paper, and, when in a natural and proper condition, as impressible under heavy, as wax is under light pressure. All that has or can be said of the proper treatment of leather to get rid of coloring matter, after it has been im- properly placed in the fiber, should be subordinated to the better method of not allowing the coloring matter ever to go in the leather at all, or certainly not to the damaging extent which would render the extreme methods of mineral bleach- ing necessary. It is possible to extract the tannin from even our hemlock bark without so overcharging it with coloring matter as to damage the buffing qualities of the leather. It is not necessary that all our leather should be white, or cream color ; any other color, if only natural and bright, is intrinsi- cally as handsome and appreciable. It is only because the red color of the hemlock is thought to be extraneous that it is regarded as objectionable. It is because this color is thought to indicate our inferior quality or workmanship that causes leather having it to be condemned. The writer saw, in one of the first boot and shoe manu- facturers' show windows in London, the best English bend bottoms stained red, or in very close imitation of our hem- lock. This was his trade mark, and had been for many years. There was no attempt at buffing, such as we ap- preciate in this country, but the bottoms were made per- fectly smooth with the the " long stick." Now, this only proves 106 THE LEATHER MANUFACTUEE. that there is no standard color which, of itself, gives value. The bright hemlock color is now sought in pocket-books, satchels, ladies' belts, book- binders' leather — and, indeed, in all ihose leathers which go to make up the "art work," of which leather is the foundation. The French word "cuir," for leather, is to-day the name of the prevailing fashionable color — and this color is absolutely fabricated from hemlock bark ; yet when it is found in sole leather it seems a badge of disfavor, to be got rid of by any means, however artificial and even damaging to the intrinsic qual- ity of the structure of the fiber. The fashionable "cuir" color can be most artistically made and preserved with pure hemlock tanning, if only too much heat is not used in extracting the strength of the bark. For fear that all may not understand what is the limit of heat permissible, it may be said that no tanner who desires to make the best color possible should use over 80 degrees of heat on his bark. Hemlock bark liquors, obtained with this limited heat, applied to pelts or hides properly prepared, en- tirely freed from all lime, will produce a color in almost exact imitation of the French " cuir " color, or, to put the expres- sion into English, the " hemlock tan color." The celebrated Russia leathers that enter so largely into the fine " Vienna leather goods " are originally of a light lemon color, produced by the willow bark with which they are tanned, and they are afterward changed by dyewoods and mordants into various colors ; the most p pular is that al- ready indicated — indeed, it is sometimes called a " Russia leather color " by way of designation, and yet all Russia lea- ther as seen in the arts is colored artificially. A curious train of circumstances developed the impolicy of " hiding our true colors" during the recent rebellion. The army ofiicers imbibed the prejudice which generally prevails THE LEATHER MANUFACTURE. 107 that oak tanned leather was far superior to hemlock, and were influential in demanding this kind of tannage in all their army equipment work, such as shoes, belts, harness, etc. All of the earlier contracts specified that the - leather should be made from " oak," and in some of the departments "white oak " tannage was called for. Soon the disparity between the price of hemlock and oak rough leather became so marked that the temptation to obtaia in some way for hem- lock leather the higher prices paid for oak became too great to resist, and curriers found a way to bleach the hemlock even to a lighter color than the natural oak, but by a process which greatly damaged the intiinsic quality of the leather. One of the first discoveries made of this fraud was the find- ing of a large lot of bayonet scabbard sheaths that had so rusted the steel which they were made to cover and hold as to make both leather and contents perfectly worthless. The writer was c vlled on by the Government to determine the cause of this damage. The decision was that, by reason of the mineral salts used in bleaching, the dampness in the at- mosphere collected an amount of moisture in the leather which caused the rust on the steel. Then how could this damage be prevented in the future ? was the practical ques- tion to be determined. My suggestion was, to strike from the requisitions the demand for " oak tanned leather," and thus remove all temptation to make artificial oak ; but this practical advice was not heeded, and, more or less, during the whole four years of our war, the Government paid for oak leather and got greatly damaged hemlock. This policy on the part of army officers cost the Government miUions of dol- lars, and the regulations under which this mistake was com- mitted are still, to a considerable extent, in force. Ihe first and hest thing to do then is not to overcharge the tannin with the coloring matter by the use of heat, and 108 THE LEATHER MANUFACTURF. second, if it is so overcharged, to get rid of it by wasliing and scrubbing and the use of vegetable acid, such as a warm sumac bath, for instance. A single liquor overcharged with coloring matter in the earlier stages of tanning will often leave its elfect so permanently on the pack as to defy all after correction. It is a mistake too often made by tanners to suppose that the coloring of the pack is effected by the last layers. Ordi- narily the color given in the handlers is carried through to the end. Start the color right, create the proper mordant in the handlers, and then strong and even highly colored liquors may be used without causing serious damage. The writer once saw a tanner attempt to make union crop leather with the usual quantity of oak bark, by putting his oak in at the wrong time; he thought he should "finish off" with oak, whereas he should have used his oak as a mordant in his handlers and early layaways ; the result was, as might have been expected — failure. There is good reason to think our English friends have made this mistake in using our hemlock extract. They have used the extract at too early a period, hoping to cover it up by their light coloring materials at the end — whereas, if they had colored their packs with terra and valonia, and put the hemlock extract in their last layers, they would have produced a different result. The English custom of allowing their packs to "sweat " in piles before " striking out the grain " is founded on a sensible idea, and the practice even now of " striking " the grain rath- er than rolling the whole substance, is based on the practical wants of the trade. By this process the pelt is held in its natural state. The thickness is maintained, the edges (backs) are rubbed up and made to appear full, and thus a market value secured which would be sacrificed if the leather were dampened and rolled as is our custom. THE LEATHER MANUFACTURE. i^J Whether the manufacturers of Great Britain and Germany will ever become accustomed to our compressing process, and give us credit for plumpness which we seem not to have, is a question to be determined by futare experience. If we change our rolling for a stamping process, and make our fiber hard, while at the same time we compress it, we certainly shall suit our German, Swiss and French customers, for this is the method followed by them in finishing sole leather. CHAPTER XII. CONSTKUCTION OF TANNEEIES— THE TUREET DRYER. HOW THE ADMISSION OF LIGHT AND AIR IS CONTROLLED IN THE TURRET DRYER— ITS CAPABILITIES FOR DRYING LEATHER IN QUICKER TIME, WITHOUT REGARD TO THE WEATHER — -ITS CONSTRUCTION, AND HOW ITS CAPACITY SHOULD BE PROPORTIONED TO THAT OF THE YARD — HOW AND WHEN HEAT SHOULD BE USED HOW TO PREVENT DISCOLORATION OF THE LEATHER SAVING OF LABOR IN THE TURRET DRYER. About the year 1864, at Sparrowbusli, N. Y., tlie first turret dryer was erected. It was a six-story structure, watli most of tlie improvements found in tlie present dryer. There is nothing new in drying leather in a tall building. Many of the old tanneries, built as long ago as 1830, had three lofts over the whole size of the tannery ; the floors in the two upper lofts were latticed, and were therefore in this respect like the present turret form of dryer. But the principle claimed for this improved turret dryer is that, both as to air and heat, there is perfect control, -whereas, with any drying loft hereto- fore in use, the damp air of the yard found its way up through the lofts, and in all cases there were opening windows from each loft, which were depended upon to admit the external air, so that substantially all the air obtained came in through these upper openings. The effect was that the leather hang- THE LEATHER MANUFACTURE. HI ing near the openings dried rapidly, while those sides hanging in the center of the loft remained unaffected, so that, before theyconldbe dried, they were required to be transferred; often they were many times " shifted." This shifting process was particularly necessary in the winter time, when the large box stoves, burning wood, placed in different portions of the lower loft, or in the yard and beam house, caused the sides hanging near to dry rapidly and gi-eatly to discolor, while at twenty feet distant the leather would be frozen solid. The difficulties and great delays in drying sole leather by any of the old methods were among the most annoying inci- dents of the tanners' life. All these are entirely removed by the turret dryer. There is now an absolute certainty as to the time when the leather will be dry, and this does not in anv necessary degree depend on the state of the weather. Among the advantages of this new form of dryer are the following : 1. Drying in one-third the time— thus saving insurance and interest. 2. Drying without regard to the state of the weather— thus at all times keeping the rollers supphed. 3. Drying much more uniform in color. 4. Drying without shifting, or labor of any kind except to "hang up" and "take down." These are some of the economies of the turret system of drying, but they might be enlarged upon. The principle claimed, as aheady stated, is the absolute control of heat, hght and air ; with these three elements under control, it will be admitted that all the advantages claimed must follow. The bunding may be any number of stories high ; some are but three or four, and others are seven and eight. Of CO .rse, to erect a building high enough to contain eight 112 THE LEATHEE MANUFACTUIIE. stories would require very heavy timbers, and from both ob- servation and experience the writer would recommend but five stories, each about seven feet in the clear between beams — ^just high enough for a man to pass with his hat on. This structure need not be made of very heavy timber, and conse- quently would be inexpensive as compared with those build- ings that run up so high. The question of convenience of elevating the leather, whether in the higher or lower turret, need not be taken into the account, as this is done by ma- chinery. The building should be about two spans of timber wide — say forty feet — with two rows of posts, equidistant from the sides. Longitudinally with the two rows of posts should run a tight board partition, with intersections at every ten feet extending to the sides. This would cut the space up into two rows of rooms of about 10 by 12 feet each, with a cen- ter passage of about 13 feet. The roof is made in the usual latticed lantern form. All the floors above the first or ground floor should be lat- ticed, and the rooms would, of course, be immediately above each other, so that, if the building were five stories high, there would be five rooms 10 by 12 feet each, standing one above the other, and there should, of course, be just as many of these rooms, or series of rooms, as would be required to dry the stock of the yard, whatever its capacity might be. Each one of these rooms will contain one pack of ahunrlred or one hundred and twenty sidos, depending upon the weight of leather, and will dry the same in ten days. This would give the series of five rooms the capacity of drying fifty packs in ten days, or about fifty sides of heavy sole leather each day. Just so many times as fifty will go into the entire daily production of the yard will the tanner require duplicates of this series of rooms. The rooms on the first floor should be supplied with steam THE LEATHER MANUFAGTUPwE, 113 pipe, laid on the floor, or raised a few inches only by strips of hard wood, covered with hoop iron. The piping furnishini;- heat for each of these rooms should be under separate con- trol, so that not only could the steam be turned on or off from each, but any degree of heat might be admitted. All the packs taken out in one day, or in two or more days in succession, should go in one of these sections, so that the condition of the leather maybe as nearly uniform as possible in each set of rooms. The leather is hung up on sticks in double rows, leaving a passage of nearly two feet between. For the first three or four days no steam should be allowed in the pipes or the section, nor should the trap doors which lead outwardly be opened but slightly if the weather is warm or the winds blow high, but in the fall, or when the weather is overcast, the lower trap doors may be safely left open. About the third or fourth day a very low degree of steam heat may be allowed in the pipes, and this may be gradually increased until the seventh to the tenth day, when it may certainly be premised that the leather will be fully dried; tlien all the sides in both tiers, and in all of the five rooms, will be dried about the same time, and may all be taken out and replaced by other sides. The writer has kno\\ai turrets to be so actively worked as to turn out stock in seven days, but ten days' time is not too much, since it is very important not to hurry the drying the first few days. It has not been stated that the center passageways should be Hghted by cross sections leading to the windows, nor that each room should contain one small window close to the top, (but to admit light only), nor that there should be no open- ings except at the base of the lower room, with the air lead- ing directly on the piping — aU these are questions of detail that will be studied by any tanner who attempts to replace ills old method by this new and better one — f yx often the gen- 114 THE LEATHEK MANUFACTUEE. eral plan here outlined must be modified to meet tlie new conditions. The "turret dryer" is beyond all question the most thorough and efficient method yet devised for drying lea- ther, and in some of its modified forms should be adopted by all tanners. The difference in the temperature of the atmosphere at the ground and at an altitude of 40 or 60 feet would, of itself, create a draft, as is well illustrated by the erection of "stacks" or "chimneys" for the passing off of smoke or gas. But if to the natural action caused by the difference in the temperature we add a little steam heat, a steady, yet moderate circulation will be maintained from the bottom toward the top or openings of this structure, carrying iipward and off the dampness of the leather, without creat- ing such violent currents of air as to injure the color. It is believed that the principle which underlies this meth- od of drying sole leather could be applied with equ.al advant- age to all other kinds of leather — calf, upper, harness, sheep, goat, and particularly such of these as are to be finished " fair," without injury to the color of the grain. Eeturning to the construction of these turrets, it may be remarked that the center passageways will be found useful in affording room to run the trucks with green leather, or to store the dry leather awaiting the roller. Some tanners pre- fer to have shutes running through each loft, down which they slide the leather as soon as dry, to be piled on the low- er floor. Others make their lattice floors of a temporary or movable structure, so that the whole contents of each room is dropped down into the lower room, including all the sticks on which the leather has been hanging. The writer does not thit k this a good plan, on the whole, since the extra labor of separating the leather from the mass of sticks, and carrying them back to their proper place, is about as much trouble as ifc THE LEATHER MANUEACTURE. 115 would be to take the sides down in the rooms, and, with the aid of a suitable barrow or truck, run them to the sHde which takes them to the dampening or storage room direct. There is a most economical elevator or lift which should be known to all tanners who propose to adopt this turret dry- er. It consists of an endless chain running from the extreme bottom to the top floor, ending under the roof. This chain should run in a wooden box, inclosed on three sides. The outward or open side will serve to attach the sides by means of hooks fixed to the links of the chain, say at distances of about four feet, depending on the rapidity with which the chain moves. The distances between the attaching hooks should be sufficient to enable the attendants to attach below and take off above the sides. By this economical method leather may be elevated to the highest loft with no more actual expense than if dried on the ground floor, and the sides, when once hung, remain until fully dried — thus saving all expense of " shifting," etc. What has been said in another place upon the influence of light and heat upon color will measurably apply to this pro- cess. Leather dried in the open air will certainly dry dark, even if tanned with pure oak, and, if tanned with hemlock or a mixed bark, will darken to a damaging extent. If cur- rents of air reach the leather while in a wet state, a like result is produced, with the addition of great harshness of grain. If a bright hght, particularly if the sun's rays reach the grain or flesh, the leather turns brown, and is perma- nently discolored. The influence of the direct sun's rays, or even the strong light of the sun on vegetation, is a good illustration of such influences on the color of leather con- taining vegetable acid in solution. The ordinary table celery is covered with earth as fast as it comes to the surface, to keep the light from it, so that it may be white and tender. 116 THE LEATHEK MANUFACTUEE. Pie plant which grows under a barrel or in the shade will be white and not green. Grass that grows under cover, excluded from the Hght, is white, not green. This law of Hght applies to all vegetation. Availing ourselves of this principle, there- fore, we say leather that is intended to be fair in color should be dried in the dark, and as free as possible from currents of air. An illustration of the " turret" dryer. with further explana- tions of its construction and mode of operation, will be found in later pages. CHAPTEE XIII. CONSTEUCTION OF TANNERIES — PLANS, FOUNDA- TIONS, ETC. THOKOUGH EXAMINATION OF PRESENT STBUCTUKES AND APPLIANCES AD- VISABLE BEFORE BUILDING — IMPORTANT CHANGES FROM THE PRESENT GENERAL USE OF STEAM INSTEAD OF WATER POWER — LOCATING ON "manufacturing" and "culinary" STREAMS A LOAM, CLAY, OR SANDY FOUNDATION FILLING IN BETWEEN VATS AND LEACHES WITH LOAM OR CLAY PLACING THE VATS THE " BUFFALO" VAT "bOx" VATS — :THE PROCESS OF " PUDDLING" IN SETTING THE VATS — UPPER CONDUCTORS SIDE AND END WALLS. As preliminary to all efforts to erect a tannery, drawings and working plans should be fully prepared. These plans should not be merely in the mind of the owner or builder, but they should be elaborately placed on paper, so that they can be well defined and susceptible of examination and discussion. The writer has seen so many expensive failures by reason of neglect in this respect, that, at the risk of being considered superserviceable, he would insist that, first of all, when the erection of a tannery is decided upon (and before the plans are drawn), extensive visitations should be made to the best constructed tanneries, where can be seen in practical use aU the best-known improvements. The characteristic readiness, and even pleasure, with which American tanners show their works, and honestly discuss the merits of their methods, leaves no excuse for any man who proposes to eyect a new 118 THE LEATHEE MANUFACTURF. yard not to avail liimself of all the experience wliicli has been obtained by others. On this trip of observation both the draftsman and the head mechanic should be of the company, and they should not stop short of visiting every tannery where a new idea can be obtained. Leaving out of view at present the question of location for the economical supply of bark, hides and other material, we will treat at present only of the proper location of the build- ings, irrespective of the markets for hides and leather, and the bark supply. Until within the last ten or fifteen years, most of our tan- neries were driven by water power, and this fact caused the buildings to be erected not only on the immediate bank, but usually the foundations were placed on the bed of a stream. This close proximity to the water was made necessary to en- able advantage to be taken of the " head and fall," thus se- curing the greatest amount of power to drive the machinery. Such locations have always subjected the tanner to great danger from the overflowing stream, and as these risks were not insurable, many men have been entirely ruined by disas- trous floods. But beyond these extraordinary risks, such locations were usually very expensive to prepare, since rocks and boulders had to be blasted and removed, and when this was done the foundations were often uneven and hard to ad- just to the conductors and vats which rested upon them. Since the substitution of steam for water power, all these difiiculties, and many more which might be enumerated, are avoided. The tannery buildings should be located near a capacious and never-failing stream of water. The stream need not be large, for any direct purpose of the tannery, but a clear dis- tinction should be drawn between " manufacturing " and " culinary" streams, as the health laws and public policy of THE LEATHER MANUFACTURE. 119 all civilized nations make a wide difference between these classes of water courses. If a tanner locates himself on a "cuhnary" stream, he is always liable to the complaints of his neighbors below him — and even on a manufacturing stream he should, as f ir as possible, avoid throwing his waste in the water way, for, according to opinions of some of our courts, he is responsible for all actual damage done even on such streams. But if a tannery is properly located and con- structed, it will be found profitable to retain and utilize all refuse animal and even vegetable matter, which so defile the stream when thrown in, and it really seems to the writer a providential and happy influence which intervenes to prevent the tanner from thus injuring himself. The location of the tannery should, if practicable, be on a loamy, clay, or at worst a sandy foundation. If possible a loamy foundation should be secured. Whoever doubts that loam is equal to or even better, practically, than clay, should try some experiments similar to several which have come within my observation. Clay, if thoroughly worked, and "rammed" with great care, will, beyoad all doubt, act as a good preservative of wood; but, by reason of the great amount of labor and care required in its manipulation, it often happens that the material is unequally worked, and spots of dry or unworked clay will be thrown in ; this per- mits the access of air, causing defective parts in the wood, and soon the soundness of the whole structure is destroyed. Loam is much easier worked, and defects in its manipulation can hardly escape detection. The experiment which is com- mended to all doubters is as follows : Take a common pail and fill with loam, mixing and mingling water therewith, until the whole mass is of about the consistency of very thin mortar ; then allow the contents to settle for a day or two, and the result will be that the water will stand on toD and the 120 THE LEATHER MANUFACTURE. earthy or loamy substance will fall to tlie bottom, in such order and compactness as absolutely to form a sandstone ; indeed, it is just this process in nature that forms the sand- stone which we everywhere see. When this loamy or earthy substance has fairly settled, holes may be bored in the bottom of the pail and the water will not percolate through, but will remain on top and finally evaporate. The principle upon which this stone formation takes place must be observed in filling in between vats or leaches, other- wise there will be failure. When the whole mass is in a liquid or soluble condition, and is at rest, the settlement bsgins, according to the law of gravitation, the denser or heavier particles dropping first, and then the next heaviest, and so on until the whole body has settled just in the order of the specific gravity of its parts. Now, it must be evident that, if the best result would be secured when pucjdhng in between the vats or leaches, the whole mass should go m together and be plunged and mixed so that this order of settlement and adjustment may be the result. When loam is thus placed in between the vats it is almost impossible that there should be any leak. The writer has seen whole yards sunk without corking any of the joints, and yet all the vats remained tight. When from any cause the foundation is defective — Avhen gravel or projecting rocks are likely to allow water course;; to be formed— the iuterstices must not only be filled, but made absolutely tight, and even new foundations must be artificially formed with loam, to the depth of one foot at least below the log conductors. If by any chance a water course should be formed under the yard, the entire profits of the tanner may run away. The tanner should remember that for a mistake in omitting to lay his foundations both deep and water tight, he is liable ever after to unconsciously THE LEATHEE MANUFACTURE. 121 waste liis liquors. When it is considered tliat tliey are al- most as valuable as malt liquors, lie will comprehend the im- portance of the greatest possible care. No brewer would hazard the possibility of a leak in his underground tanks, however small, nor should a tanner. When the foundation ground is thoroughly prepared — then, and not before, should the log conductors be placed. The vats may rest firmly on the conductors. The point of contact should of course be at the ends, where the tube con- nections are to be made. But in addition to the rest on this log conductor, timbers at least 6 by 8 inches should be thoroughly imbedded in the loam formation, not more than two feet apart, thus supporting the vats uniformly and equal- izing the strain. Otherwise the vats will certainly leak after a short time. When the conductors and supporting timbers are placed evenly over the whole yard surface, there should be a renewed attempt to puddle with a thin loam mixture— so thin that the smallest aperture or crevice imdemeath will be filled etfectually. At this stage of the construction there come in at least two different kinds of vat builders, with their plans of construc- tion, both having merit. The first plan is known as the "Buffalo" method. This designation comes only from the fact that the Buffalo tanners first adopted it. It contemplates the foundations prepared as heretofore indicated ; upon these foundations, plank, which with this plan should be at least three inches thick, are closely jointed and laid over the whole surface, and then spiked to the timbers. Sometimes these plank are tongued and grooved, sometimes only jointed up close, and when the plank are half seasoned the joints may be trusted to close by the action of the dampness swelling them tight ; but a corking joint, well filled with oakum, is, in 122 THE LEATHER MANUFACTURE. my judgment, much the safest reliance. After the flooriuc; plank have thus all been evenly and permanently laid and corked, the grooving plane cuts the grooves, into which the planks of the vats are inserted endwise, so that, when the vat is formed by these prepared plank standing endwise, resting in these close-fitting grooves, each side and end of the vat is keyed up by a "wedge plank." The only advantage that this form of vat has over what is termed the "box" form is that there is no space wasted be- tween the vats, and, of course, if leaks occur, they can only be from one vat to another. In locations like our large towns and cities, where land is very valuable, this method of con- structing vats has generally prevailed, as it saves at least four inches space between them. The writer cannot, how- ever, but think that, both on the ground of economy of con- struction as well as safety, the box form is to be preferred. The ordinary "battened" and "box" vat iSj in my judg- ment, the best, because the safer form, where lumber is cheap and where space is of no value, as is generally the case in new territory, where our tanneries are usually constructed. This form of making the vats may be thus described. After the preparation of the foundations, as heretofore indicated, boxes made of plank, either two or three inches thick, bat- tened together, are placed side by side and end to end over the whole surface. The battens are " dropped in " and "pass each other;" or, to use the mechanical term, "joints are broken," so that the battens form supports to both sides and ends of the vats that come into contact and adjoin each other. When thus placed, connections are made, by tubes through the bottoms, with the log conductors beneath, and the seams are thoroughly corked with " spun " oakum. The best form of making these seams, and the most reliable and economical method of making tube connections, it is impos- THE LEATHER MANUFACTUEE. 123 sible in words to communicate, but it may be assumed tliat whoever really intends to avail himself of these suggestions will think it worth while to investigate more fully before he attempts to put in practice ideas which, at best, are very imperfectly described in these chapters. There are economic methods of preparing the plank for these vats, which have been employed within a few years, which put to shame the older hand methods. Whether the plank for vats should be made of pine or hemlock timber, and whether from plank two or more inches in thickness, are matters of detail, which it would be foreign to the object of this chapter to consider. After these box vats have been placed, corked, and the proper tube connections made, then comes the important work of puddling. Many yards have been ruined for want of care in this particular. The vats must be filled with water just as fast as, and no faster than, they are "puddled in" from the sides and ends. Some tanners think it sufficient to hold the vats in place by putting weights on the top, or by studding from the floor upward, but neither of these forms should be relied upon, since the pressure of the concrete, or puddhng, from below, is very great, and it should be met by an equal, uniform, downward pressure — such as only the weight of the water filling can give. The loam which is used to fill in between the vats should be placed convenient to the yard, should be prepared in tight mortar boxes before it is run in, and so thoroughly mixed that it will run in box shutes to any desired spot. Carrying in pails, or otherwise handling, makes slow work, and too often induces the throw- ing in of the dry loam and the attempt to mix by plunging. This form leads to air holes and imperfect puddling. The whole process should be carried through on a uniform sys- tem, and no slighting or imperfect work should be permitted. Mr. James Clewer, who was the author of this system, THE LEATHER MANUFACTURE. always claimed that it was possible to so perfectly puddle vats with loam as to render corking unnecessary. Indeed, he did estabhsh two or three yards on this plan without any corking whatever, and to this day (now more than thirty years afterward) the yards do not leak outwardly, though some of the seams leak inwardly— that is, the drip and drain- ing of the loam finds its way through the seams, and dis- colors slightly, but only occasionally, the sides that come in contact with it. By omitting the precaution of filling the vats with water before puddhng, the result will be not only that the vats will be raised from their foundations, thereby disturbing the tube connections, but the sides and ends will be forced in- wardly, so that ever after the shape of the vats will be dis- torted and their capacity lessened. The "caps" or alley flooring resting on the tops of the vats should be often raised to see that the fiUing has not given way. If, as is quite likely for the first few months, such giving way or sinking is noticed, great care should be observed in refilling. When once the loam has thoroughly settled and become fixed in place, it may be considered cer- tain that a perfectly tight yard is guaranteed for aU time. Some tanners have an upper system of conductors through which they supply their vats with new and strong liquors. These, when new and perfect, are very convenient, but such conductors are not to be trusted. After a few years they be- come decayed and leak, to the great damage and waste of tlie hquor. No care in the placing seems adequate to keep the air from these wooden structures when made so near the sur- face, and when the air does reach the wood it is certain to rot it in four or five years. It is for this reason the use of these upper conductors between the vats cannot be recom- mended, even where they are partially covered with earth. THE LEATHER MANUFACTURE. 1^0 It is far better to have the upper conductors wholly above the top of the yard, either in open shutes or m tight log con- ductors, where any leak can be detected. When a tannery is located on an earth foundation, the side and end walls need not be extended to the lower foundations. Excavations can be made, the yard placed and filled in, and side and end waUs may be commenced on timbers laid within two or three feet of the surface. If the timb-r is laid below the frost, and below the point reached by the air, it will last forever, and it will be safe to lay a brick, stone or concrete wall from this timber foundation upward, say two or three feet above the surface of the ground, on which the sills of the building may finally rest, beyond the reach of the damp earth beneath. If the filling in on the outside of the vats has been thoroughly done, this filling gives a more secure foundation than the natural earth, and will save much ex- pense in the foundations. If it is thought desirable, as it is in the opinion of most tanners, to erect the frame before setting the vats, the frame can be supported by temporary posts, running down to the foundation, and the making of a more permanent foundation may safely be left till the fiUing in is done, as here indicated. It will be useful for aU tanners to remember that hemlock is just as lasting under ground as pine or other wood. CHAPTEE XIV. CONSTRUCTION OF TANNERIES— LEACHES. BOUND OB SQUARE LEACHES THB' DURATION OF LEACHES ABOA'E AND SUNK IN THE GROUND HOW TO BUILD A ROUND LEACH HOW TO MAKE AND SET LEACHES IN THE GROUND THE CAPACITY OF THE SETS OF LEACHES TO BE PROPORTIONED TO THE SIZE OF THE TANNERY, The form and construction of leaches is a problem of great importance to tanners. Shall they be round or square ? Shall they be above or underground ? Shall they be con- structed of wood, stone, or brick, and, if the former, then shall oak, hemlock or pine be used ? How can they be most economically constructed ? How long will they last made of either of the materials or forms named ? All these questions, and others besides, will occur to the practical tanner who contemplates building a tannery ; they are included in the general question. What kind of leaches are the most econom- ical for tanners' use ? Since the introduction of the "sprinkler leach" most tan- ners have made their leaches round. It is quite a mistake to suppose that the patented improvement covers the use of any kind of a round leach. It is true, probably, that a round leach is better adapted to the " sprinkler " than any other form, and for this reason the patentees have adopted it. There certainly is nothing novel in this form since, on the THE LEATHER MANUFACTURE. 127 Continent of Europe, all tanners use round vats, and leaches, too, whenever they use leaches at all. If, therefore, tanners conclude that round leaches are preferable to square ones, they are quite at hberty to use them without any patent claim. It is safe to assume that no leach made of wood, however constructed, will, if placed above ground, where air has access to it, last more than four or five years ; by that time le )ks will become so plenty as to necessitate a renewal. It is said of a chain that the whole is no stronger than its weakest link ; so it may be said of a wooden tank or leach — the whole is no more lasting than its most imperfect stave or joint. Practically, then, Avhenever a single defect occurs the whole leach must be abandoned. It would never be wise to put new staves in a defective leach, anymore than the house- wife would think of mending an old water-pail by replacing a defective chime. In considering, then, the economy of round leaches placed above ground, we are to estimate the duration of one of these structures by its single parts, and not by its whole structure. The experience of the most successful tanner using these round leaches above ground will show that four, or at most five, years is the duration or life of one of these structures. Reference is here made to the ^/(//ii round leach — a leach that can safely stand full of strong liquor without " receiving leaches" or "drips" standing underneath, for in this manner these leaches have always been constructed and worked. But if a tight plank flooring should be constructed, and the leaches placed above it, the writer never could understand why attention should be paid to a small leak ; indeed, if the leach was never filled with liquor, why should there be any pressure on the joints ? Why should there be any leak, or if there was, why should any loss or injury result? This as- 128 THE LEATHEE MANUFACTURE. sumes that tlie bark is percolated by tlie liquor as fast as tho latter passes the sprinkler; that the liquor never floods ihe bark— and, so far as the principle of the patented improve- ment is concerned, this form of operation would more fully answer the purposes of the patent than if a portion of the bark was flooded — that is, had standing liquor in the leach. Indeed, just to the extent that liquor stands in the leach the patented idea is lost sight of. It then becomes a press, ■ rather than a percolating or sprinkler leach. The form of running these leaches should properly influence their con- struction, for there is no reason why a sprinkler leach, run upon the true principles of the patent, should ever rot or wear out, since, so long as the staves stand up or the bottom remains in, it will inclose and hold bark ; and, so long as the staves would hold together to guide and confine the hquor in its downward course, a sprinkler leach would still remain to perform its ofiice. Of course this defective structure would necessitate a tight plank flooring beneath ; but, so far as the writer is informed, the patentee has never recommended this form of handling these leaches, and until he does we must treat them as tight leaches, and subject to be renewed once in four or five years, under the most favorable circumstances, when they stand above ground. In deciding upon the material to be used in buildinf^ leaches, it should be understood that young, sound hem- lock is just as likely to last the allotted time as the best pine ; but care should be taken to have the staves made from uniformly young trees, perfectly sound and fresh— that is, just peeled and sawed, and not from either old timber or that which has been lying two or three years before being sawed. Young hemlock trees, say not more than one foot in diameter, sawed into staves six inches wide and two inches thick, can be manufactured into tank or leach staves almost as fast as THE LEATHER MANUFACTURE. 129 they can be picked up and passed twice tlirougli the hands of the employe. The writer gives a little detailed instruction upon this point, since, through unreflecting employes, he was once made to suffer many thousands of dollars' loss for the want of a proper knowledge of the economies of this subject. After the plank Ijave been sawed of the requisite length and width — usually seven feet long and six inches wide — the staves in this rough form are beveled by a circular saw on both edges. This bevel, of course, is made to adjust to a circle of 8, 12 or 16 feet, depending upon the diameter of the leach. When the staves are thus uniformly beveled, they are laid in a circular form, ten or fifteen at a time, and are chimed out by a " chiming" or " grooving plane." After be- ing thus formed they can be set up around the round bot- tom into which they are driven, and where they are held to- gether by iron hoops, without calking ; such a leach will certainly be tight. The saw that makes the bevels should be about eight inches in diameter, and be very straight, fine and even in its set, so that a perfectly uniform surface may be secured. It is said "uniform," rather than "smooth," because it has been often demonstrated that such a surface, when pressed to- gether will form a. tighter joint than can be secured by the hand plane, however much pains may be taken to secure smoothness. Very great attention should be paid to the character of the material. Hemlock is so cheap and abund- ant that none need be taken that is not perfect, both as to soundness and uniformity of thickness. In making the bottom of the leach, hemlock plank, plump two inches thick, should be used if the leach is to be eight or twelve feet in diameter, and if it is to be sixteen feet in di- ameter then the plank should be three inches in thickness ; 9 130 THE LEATHER MANUFACTURE. in botli cases the edges should be chamfered down to a uni- form thickness of two inches " scant." On the supposition that the leach is to be made twelvn feet in diameter, the plank ma J be sawed sixteen feet long, whgn they will cut into bottom plank to good advantage. But it is seldom Avorth while to a ttempt to economize so closely as to save the whole of hemlock timber, and therefore, at the expense of a little possible waste, oaly perfect plank should be used in the bot- tom. These, after being square-edged with a small fine-set circular saw, should be laid down on a platform bench, and firmly griped to,^ether, secured by a temporary batten ; when thus placed a circle should be inscribed the size of the pro- posed leach. With a small whip sav/ this line should be very carefully followed, taking great care to make the cut square, and at a right angle with the surface of the plank. If this is done with care and with a suitabl}^ straight saw, there need be but little after-work with the plane to make the circle smooth and otherwise perfect. If care has also been taken to have the plank originally sawed of uniform thickness, a very little work with the plane will bring the edges to a uni- form thickness, so that when put together the outer rim of the bottom will exactly fill, and fit the chime groove in the stave, making a reasonably good, tight j int. "We are now ready to set up our leach, and we want round hoops of at least five-eighths or three-quarters irom. The lengths should, as far as possible, be purcliased to suit the size of the leach. Usually this round iron comes twelve feet long, but it may be obtained of any length desired. There should be but one joint for each hoop — a sufficient length of iron being welded together to go completely round the leach — and the ends should come together in a cotterel, which may be of cast iron or hard wood. If one of the ends of the iron should have a screw cut on it for six inches, while THE LEATHEll MANUFACTURE. 131 the other is firmly fastened in the cotterel, a nut and wrench will draw the hoop as tight as it could be driven, if the form of the leach was tapering in shape, as on a pail or ordinary wash tub ; but as it is desirable to have these leaches of uni- form diameter, this form of drawing together and holding the stave must be resorted to. There is nothing difficult or expensive in constructing this form of leach, if the proper skill and machinery are at hand, but without this machinery and this knowledge they are very expensive, and often fail of being tight. With the small saw and mandrel, which cost about thirty dollars, and a chiming plane, which will cost about eight dollars, these round leaches may be put together with ordinary carpenters' tools at a very inconsiderable cost. The cost of the labor need not be over ten dollars for an ordinary leach, twelve feet in diameter, and seven feet deep in the clear. The expense may be increased by a greater regard for permanency in its construction, as the material may be clear pine or oak, the hoops may be of heavier iron, and instead of four hoops (the usual number) there may be six. But in this, as in all tannery construction, as much simplicity and cheapness should be observed as is compatible with the service to be performed. The iron hoops used will last during the lifetime of several wooden struc- tures. On the whole there can be no doubt that round' leaches, constructed as here suggested, should always be employed when the leaches are to be used above ground ; hni for underground leaches, or leaches filled in with earth, quite a different construction is suggested. Until the introduction of the Allen & Warren sprinkler leach, square leaches set in the gTound, in a packing of loam or clay, were in general use, and to-day are not abandoned even by our best tanners. A set of these leaches, properly placed and filled in, will last for twenty or thirty years ; in- 132 THE LEATHER MANUFACTURE. deed, with sliglit repairs to tlie top planks, they will last dur- ing the lifetime of a tannery. The writer knows of several sets that are now in good order that have, with slight repairs, been in active use for more than a quarter of a century. The preparation of the gi^ound on which these leaches stand should be made with even more thoroughness, if pos- sible, than that of the yard itself, since there is more weight resting on it, and more disturbance from the flow of currents of water. If the leaches are constructed with proper open- ings in the bottom, through which the spent tan is wnshed after the leaching process is over, then more than ordinary care should be observed in placing the under conductors, otherwise air will reach the plank flooring and cause it to decay. In all locations where a flow of water can be secured on the top of the leaches, provision should be made for this to wash out such portion of the spent tan as may not be wanted for the furnaces. Sometimes, however, the nature of the stream is such that tanners are not permitted to throw their refuse tan in the water way, and in such cases this economical arrangement cannot be availed of. Ordinarily' these square sunken leaches are of 10 by 12, 12 by 14, or, in exceptional cases, 16 by 201eet, surface meas- urement,'and usually about seven feet deep. If the leaches are of the smaUer sizes, then planks two inches thick are quite sufficient; but if the larger size, then planks at least three inches thick should be used; not more, however, for the economical reason than from the fact that the press can be better controlled in the smaller sizes, does the writer commend this form of leach. Indeed, the number and size of leaches should correspond to the size of the vats in the yard. The covering of one leach of bark should make one vat of liquor. There should certainly be no fractions. It should either be one, two, three or four vats of hquor. At- THE LEATHER MANUFACTUEE. 133 tention to this seeming detail will mucli simplify the manipu- lations afterward. The preparation of the plank for these leaches can be made by the same saw and mandrel which has been com - mended for the round leaches ; even the calking seam can be formed with this saw. No joint can be made with a hand plane that will hold oakum so firmly as with this saw joint, and the oakum joint is made much truer by the saw than it can be made with hand labor. When the ends, sides and bottoms have been battened properly, they are put together as in the case of the vats de- scribed in a previous article. Indeed, these leaches are but so many vats enlarged in size. In Great Britain the tanners make use very largely of brick and cement to form their vats and leaches. No doubt these materials make a very substantial structure, and as erected there, in cities and towns, and intended to last for all time, this construction may be the best. But some at- tempts made in this country to use this material have resulted in staining the leather. Whether this difficulty could not be overcome with us, as the English tanners claim it is with them, it seems hardly worth while to consider, since timber is so much cheaper here than brick, particularly in the country, where all our tanneries are built. Wood plank will last fifty years, sunk in our usual way, and that is quite as long as our civilization wiU tolerate the existence of a tan- nery in one location. CHAPTEE XV. CONSTEUCTION OF TANNERIES-FEAIHE WOEK AND LOCATION OF BUILDINGS. WHY THEY SHOULD BE ONLY ONE-STOBY HIGH FOR THE YARD AND BEAM HOUSE SAVING IN INSURANCE BY SEPARATING THE BUILDINGS CON- VEYING LEATHER TO THE " TURRET" DRYER TRANSMITTING POWER TO DISTANT BUILDINGS— PROPER SPEED FOR BARK MILLS AND ELEVA- TORS SIMPLE PROVISIONS AGAINST FIRE AND BREAKAGE, AND TO PRE- VENT DUST. A modern tannery is quite a different affair from one of the early Greene County (N. Y.) structures. The various im- proved methods of heating and obtaining power have ren- dered it quite unnecessary to crowd into one buildicg, as formerly, bark mills, rollers, hide mills, drying lofts, yard, beam house, sweat pit, etc. Heat and power can now be used without limit, and wherever their use can be made to economize labor or cheapen insurance they should be em- ployed. That great advantages are secured by a one-story structure over the yard and beam house will be conceded when the following points are considered : 1. The timber need only be heavy enough to carry and uphold the roof, not forgetting, of course, its probable load of snow in winter. 2. No apprehension need be felt about the falling in of the structure for a long time after the usual decay of the timbers THE LEATHER MANUFACTURE. 135 commences, since they can be replaced without inconvenience, there being no heavy superstructure to sustain, whereas a building with lofts above, often filled with wet leather, is al- ways an object of soHcitude to the tanner; he is constantly studding up and "supporting" the building to make it safe for the workmen. Besides, these high structures are subject to the action of the wind, which much weakens their joints and fastenings. 3. The insurance is only one half the price of what was paid on the old and high buildings. Although these one- story structures have now been in use for ten years or more, several hundred of them being in existence, not a single one has yet been destroyed by fire, and if this record shall not be changed by further experience, we may reasonably expect a still further reduction in the rate of insurance. In fact, with an abundant water supply and efficient service, a one-story tannery cannot be wholly destroyed, for nothing but the roof could burn, and as this can be reached from both above and below with ordinary water buckets, the progress of the flames can be stayed in almost any case of fire hkely to happen. Be- sides, the condensation of water from the steam of the yard always keeps the roof boards and covering water soaked, so that fire would not spread rapidly, if at all. 4. A building of one story for the yard gives opportunity for a high ceiling and good ventilation. It has, however, this single disadvantage — that in winter it is much more exposed to the frost, although, practically, ice seldom forms in a yard of this construction. Indeed, experience has shown that with a few coils of steam pipe running around above the sills there need be no cold fingers of the workmen. This one-story structure should have a flat roof (one foot pitch in ten) cov- ered first with boards and then with asphalt paper and gravel, by a process universally in use. 136 TSE LEATHER MANUEAClrfEl!. So far, then, as tlie yard and beam house are concerned, a one-story building is the most suitable structure ^ But how shall the tanned packs begot to the drying loft? Heretofore trap doors have been placed in each bent of the building, so that little more was needed than to open the trap and hook the sides from the yard beloAv, and thus pass them up by hand from loft to loft. This seeming convenience prevented any change from the old method for many years. Tanners not unnaturally reasoned in this way: "We have a yard and beam house, and they must be covered with a roof ; the same roof can equally cover our drying lofts, and as our dry- ing loits must have a capacity as large as our whole beam house and yard, in order to dry our stock, why should we not make our structure strong enough to carry all this under one roof?" Besides, they have reasoned : "Our insurance covers our stock in both yard and loft, and at the same price ; why should we go to the expense of erecting a separate struc- ture, where our insurance would be divided, without any com- pensating advantages in the way of reduction of rates?" Thus reasoning, our tanners went on from year to year erect- ing new yards under former plans, until within the past ten years, during which many have been induced to break away from this old method, and are now building turret dryers in connection with the rolling or finishing lofts, connecting these with the yard by tramways, hung from above in some in- stances, and in others with bottom rails of wood, these tram- ways running cars through the center of the yard, extending out to the drying lofts. The form of erecting these tramways varies with each location. Where a tannery is situated on level ground, accessible on all sides by a horse and truck, probably there is not a more economical way of transferring the wet stock from the yard than by this means. In this case the tanner can have openings from his yard at Ire- THE LEATHER MANUFACTURE. 137 qiient intervals, and the nearness and saving of transporta- tion of tlie wet leather in the yard will compensate for the cost of the service of the horse and cart, over and above a tramway through the center of the yard, to which all tanned packs must be brought. The latest and most approved method of locating the buildings so entirely separates the yard from the drying lofts that the fire risks are greatly reduced, for the yard and beam house are one risk, the leaches and bark miU another, and the furnaces and boilers stiU another. The building contain- ing the latter should be placed at least 100 feet from all other structures, and in itself made perfectly fireproof— that is, there should be no wood anywhere near the structure con- taining the furnaces and boilers. So arranged, it is found practicable to run steam power off in any direction and al- most to any distance. The most economical way of running off this power is by means of steam pipe, thoroughly pro- tected with ashes, loam or clay, weU packed in a box sur- rounding and inclosing the steam pipe. The engines that drive the machinery may be in distant buildings. Some tan- ners drive their machinery at a distance of from 300 to 1,000 feet from the boilers, and the coudensation does not seriously affect the power, a portion of which is necessarily lost, but when wet spent tan is burned this loss has no commercial value. It has been demonstrated that steam power can be con- veyed in pipes more economically than by running shafting ; that is, wherever power is required a steam engine should be placed and steam conveyed to it, rather than to depend on one central engine, and either "belt" or "shaft" off Engines are now constructed so strong and cheap, and to run with so Httle attention, that one engineer can take care of two or three with the same facihty as one. The steam valves are opened 138 THE LEATHER MANUFACTUEE. in the morning, and are not shut or otherwise disturbed until noon, and then again are opened at 1 p. m., and not closed until sundown. So different is this practice from the old method, and the care made necessary by the defective character of steam engines, as formerly constructed, that engines may now be multiplied to any required extent without making it necessary to employ an assistant engineer. It may be safely estimated that a one-story yard and beam house, isolated at least 100 feet, can be insured for 1| per cent., while 3 and even 4 per cent, is now charged on ordi- nary tanneries constructed after the old methods ; but no in- surance is needed on the leather in the vats, for neither the leather nor the vats themselves will burn, even if the frame- work above is destroyed. The turret drying loft (of which mention has been suffi- ciently made in a previous chapter) should be near the yard, and should be classed in the same risk ; but the leach house and bark mills should be in an opposite direction, and as far as possible from the central or boiler house and furnaces. Where the ground will permit, the boilers and furnaces should be in the center, the leach house and bark mills fully one hundred feet to one side, and the yard and turret drying lofts as great a distance in the opposite direction. This will bring the important structures two hundred feet apart, and if the boiler and furnace building is built as it should be, of stone or brick, and is not over jfifteen or twenty feet high, there is really an unobstructed space of two hundred feet be- tween the main fire risks. There is really no manufacturing- structure in the country so free from accidents by fire, when thus constructed and situated, as one of these one-story yards and beam houses ; and the drying lofts, always filled in part with wet or only partially dry leather, have a moist or damp atmosphere which, with steam pipe only used as heaters, THE LEATHER MxYNUFACTURE. 130 renders anytliing like accident from fire almost impossible. The natural, and, indeed, tlie only fire risk about a tannery, comes from tlie bark mills and bark elevators, and in a .vast majority of cases the fires which consume so many tanneries proceed f r om this source. How can this risk be lessened or altogether avoided? The bark mills and elevators should have a slow motion. No mill should run above sixty to eighty revolutions per minute, and the elevator belt should run slow enough to enable the eye to take in and count the buckets or boxes as they pass a given point. The sliovers and screen should move slowly, for besides the friction which causes fires there is much more wear and tear to a quick than to a slow motion, and power is also lost. An improvement has of late been suggested to suppress the dust arising from the fine ground bark, as follows : A steam pipe, half an inch in diameter, connected with the nearest direct pipe from the boiler, is brought to the under- side of the mill ; a very small jet of steam is allowed to es- cape, to dampen by condensation the bark as it comes from the lower throat of the mill, and before it drops into the con- veyers. This steam pipe could be so placed that if fire should occur in the elevators, from friction or otherwise, a full head could be turned on by the attendant, and steam forced upward through the entire length of the elevator box. This, therefore, may be regarded as an inexpensive coniriv- ance to prevent dust, and also as a great safeguard against fire; and now that steam is so cheap and abundant there seems no reason why it should not be adopted by all tan- ners, especially as it is regarded by insurance companies with great favor. Bark elevators are liable to get choked and stop ; when this occurs the bark accumulates and gets packed in the lower part of the mill ; great friction and dan- ger from fire arises from this source, and to avoid the danger 140 • THE LEATHER MANUFACTURE. an "overflow" or space under the mill slioulcl be provided. But a "tell tale" sliould be put on the elevators, plainly in the sight of the bark grinder, so that he can see when there is a stoppage. Some tanners think it a safficient precaution to have an openmg in the elevator for this observation ; but a "tell tale " should also be ^jlaced on the elevators, and this small and inexpensive lever should, in its rising and faUiug motion, indicate its action by a sHght noise, so that if the eye is otherwise directed the ear of the attendant will notify him of the danger, which is from breakage as well as fire. OHAPTEE XVI. THE EOSSING OF BARK. THEORIES OF THOSE WHO ADVOCATE ROSSING ITS COST DIFFICULTY OF ROSSING WITHOUT TOO GREAT LOSS OF TANNIN STRENGTH OF LIQUORS WHICH MAT BE OBTAINED FROM ROSSED AND UNROSSED BARK POSSIBLE ADVANTAGE IN ROSSING BARK FOR EXPORT IN THE " LEAF." To wdiat extent, and under what circumstances, should bark be rossed before being ground for tanners' use ? If credit be given to the statements of parties interested in the manu- facture and sale of rossing machines, tanners will be led to the conclusion that rossing is an absolute economic necessity. As the writer does not agree with this sweeping conclusion, and yet believes that there are circumstances under which it is profitable to ross bark, the hmitations which should govern in this matter will be briefly considered. The theory on which the rossing of bark is advocated may be thus stated : 1. The outer ross, or dead bark of the tree, contains no tannin. By the exposure of its weather-beaten surface to tbe rains and winds, all but the woody, fibrous structure has been destroyed. To place this porous, spongy, woody fiber in contact, as when ground, together with the extractive and tannin matter of the live portions of the bark, which are charged with tannin, is to absorb and dissipate this valuable 142 • THE LEATHEE MANUFACTURF. XJi-oduct to no purpose. In fewer words, this Avoody fiber will thus be fanned, and this it is claimed is Avasteful. 2. The space which this ross occupies in the leach displaces so much good bark, and to this extent retards the leaching by lessening the capacity of the leaches. 3. This dry ross is a valuable fuel, and can be used to some advantage in the generating of steam or for other purposes. Against these advantages should be placed the cost of ross- ing, which is quite inconsiderable, if the advocates of ross- ing are to be credited. Conceding all that is claimed for this practice, it is impossible by any machine yet invented, or even by hand labor, to separate the worthless ross from the live bark so exactly as to make the process profitable for ordinary tanners, who buy and use their bark at home in the interior locations. Let any tanner who doubts this statement exam- ine carefully the ross coming from any rossing machine. Let hiiii place a limited quantity under the influence of hot water, and the tan liquor present will be a convincing proof of the inexpediency of the practice. Or let him take a piece of bark no more than one foot square, weigh it carefully, and then, by hand process, with the aid of a sharp knife, let him attempt to remove just the colorless dead ross, and no more, taking great care not to touch the hve bark. After this is done contrast the percentage of i^ejected ross with the per- centage obtained by means of the rossing machines, and the result will show just how much live bark is taken for ross, to burn up, by the use of the machine. This latter experi- ment, conducted never so carefully, will also prove how im- possible it is to divide exactly and positively the dead and worthless from the hve atid valuable bark. If it cannot be done by hand, even in a small experimental way, how much more impossible is it to do with a machine which cuts the thin and thick bark ahke— notwithstanding all attempts to THE LEATHER MANUFACTURE. 143 Riljast the knives and rollers to suit tlie substance of the bark. •The testimony of tanners differs as to the percentage of ross removed ; most of them, however, agree that even one- iif th, or 20 per cent., is about the average loss. Some chemi- cal tests of the comparative strength of rossed and unrossed bark have been made, and, naturally enough, the percentage of tannin in the rossed bark has been found in excess of that in the unrosseil. But a recent and a more satisfactory ex- periment gave the following results : A pi'^ce of average hemlock bark was weighed — we will suppose the weight to have been sixteen pounds. This piece was first cut evenly in two parts, and both parts were afterward made to weigh exactly alike. The ross was carefully removed from the one piece by a hand knife ; (only about one-tenth of the weight was removed, showing the care with which it was done.) Both pieces were then separately ground fine, and ]ea<''hed, great care being observed to continue the equal condition all through the experiment. The result was, by the barkonieter test, the extract obtained from the unrossed portion stood higher, that is, indicated a greater degree of tannin, than that portion which had been rossed. This is an experiment which any tanner can try in a few hours, and at small cost of time and labor. If the experiment is tried accurately, it will be found that, without considering the cost of rossing, there is a positive economic loss in the process. In no in- stance, however, has the strength differed equal to the loss of the ross, which we assume to be 20 to 25 per cent. The experiments show that hemlock bark that is rossed will give 8.66 per cent., while the same bark not rossed will give 7.13 per cent. The experiment was made by a celebrated Boston chemist in the interest of the patentee of a bark rosser, and may at least be taken as the most favorable result which can be produced. 144 THE LEATHER MANUFACTURE. If this is the result of the comparative strength of bark, rossed and unrossed, we are left to consider on the one hand the cost of rossing, and on the other the value of the dry material. The cost of rossing, independent of grinding, may fairly be placed at fifty cents per cord, and the dry ross ob- tained equal to 400 pounds. Is 400 pounds of ross worth fifty cents? Of course this would depend upon the value of fuel in the locality. To the ordinary tanner the dry ross is worthless, and wou^d hardly pay for its removal, since the wet spent tan furnishes far more steam power than suffices for driving the whole machinery of the tannery, and dry ross is a poor substitute for wood anywhere else than under a furnace. But there are circumstances which would justify rossing as, for instance, if bark had to be transported long distances, where tlie cost of transportation was a considerable item of the value ; or, if the bark had to be " baled," and the freight was based both upon bulk and Aveiglit, then would it be es- pecially necessary to ross. It has often occured to the writer that both the English and German tanners would find it prof- itable to buy our oak and hemlock bark and closely ross and bale for shipment to their market. Kossed bark in the " leaf" wiU occupy one-quarter less space than when "in the rough," and with care may be so com^pactly placed in a bale as to make solid stowage — so solid, indeed, that no ordinary lev- erage can compress it. When thus baled, and bound with wire, there can be no doubt that bark could be sent to Europe from many of our Southern ports to advantage. The cost would be as follows : Original cost of oak bark, per ton $10 00 Cost of freight to seaboard 4 00 Cost of baling and rossing 2 00 Freight to Liverpool 5 00 Total S^rOO THE LEATHER MANUFACTUEE. 145 Southern oak bark, thus rossed and baled, would give Eu- ropean tanners better and cheaper tanning material than they at present employ from any barks in the " leaf " or "chip" which they now use. Whether " extract " from this bark could not more economically be sent abroad, is quite a different question, which the writer will not here enter upon. 10 CHAPTEK XVII. UTILIZATION OF TANI^EEY EEFUSE. BURNING THE WET TAN GLUE STOCK IMPORTANCE OF KEEPING THE PIECES PURE AND SWEET PRESERVING, CLEANSING AND DRYING THEM USES FOR CATTLE HAIR THAT WHICH COMES FROM SWEAT OR LIMED STOCK ^WASHING, DRYING AND PACKING ^FERTILIZING LIQUIDS FROM THE LIMES AND SOAKS. Previous to the year 1852 it was customary in all tlie tan- neries of New England to dry, or partially dry, in tlie open air, all the spent tan from the yard and leaches, and store during the summer months for winter use, not only for heat- ing the liquors, but, in exceptional cases, to generate steam to furnish the power for the ordinary work of the tannery. Even up to this day the practice is regarded as most eco- nomical by the upper leather tanners, and such others as do much finishing. None of the patented, or unpatented, meth- ods of burning wet tan can secure as good a result with wet as they can with dry tan. Experience has shown that from one-third to one-half the effective heat-producing power is neutralized in driving off the water. In other words, there is no method of burning wet tan that does not first evaporate the water. Therefore, when there is an inadequate supplj' of tan, and it is convenient to dry it, it is always better to do so. But in the case of our sole leather tanners, they have a THE LEATHER MANUFACTURE. 147 surplus of wet tan, and to waste it by burning a profuse quantity is to save the expense of otherwise disposing of it. In the year 1852 Mr. Joseph B. Hoyt conceived the idea of burning wet spent tan in a detached brick furnace, and did for the first time in America succeed in obtaining the poAver to drive his inachinery by this agency, unaided and alone. This wa^ done at his tannery at Woodstock, Ulster County, N. Y., and the event has been made memorable by the great success which has attended the practi(3e ever since. This improvement revolutionized the construction of our tan- neries. It rendered water power of little or no value. It caused tanneries to be located upon open flats, where access could be had from all parts to the buildings, and took them from the banks of the streams, where floods and overflows did yearly great damage ;'it rendered unnecessary the use of wood or coal for the heating of hquors, or the warming of the lofts, and, by the unlimited and inexpensive use of this newly- acquired agent, labor saving machinery was introduced every- where. The controversy about the priority of the invention or use of wet spent tan, commenced in 1869, occupied the attention of one of our courts for six years or more, and the decision finally reached was that Mr. Hoyt and his agent, Mr. Crock- ett, did introduce these wet tan burning ovens as early as 1852, and by their use a result was obtained equal to any which has been secured by any improvement since made. Notwithstanding the publicity which has been given to the construction of furnaces for the utilization of this refuse, there has been no one specific plan that has received general commendation. So many of these furnaces have been adapt- ed to the condition of the structures already in existence, that, with the exception of those tanneries built within the past ten years, there has been no consistent and harmonious 148 THE LEATHER MANUFACTURE. plan of construction. Witli a fuel so abundant, and witlial so worthless, economy in tlie consumption was best studied by practicing tlie most wasteful methods, and hence it has been customary for tanners to economize in the construction of their boilers at the expense of their fuel. "Log" or "cyl- inder " boilers being much cheaper and more durable, they have in many instances been introduced instead of "flue" or " tubular " boilers, not because they were rSore economical, but in truth because they were more w^asteful of fnel. Sev- eral of our tanners have been compelled to construct brick furnaces outside and independent of their ordinary boilers, in order to " get rid of " their surplus spent tan. As time goes on, however, and as we come more generally into the use of mechanical power, there will be less solicitude to get rid of this refuse without bringing it within our service. No town or city is without its mechanical appliances, and if the power or heat is not required for the tannery, it can be ap- phed to some other purpose. It may be sent off to the dis- tance of several hundred and even several thousand feet to drive an elevator or an engine, or warm some dwelling or manufactory. There is no reason why all the power should not be utihzed, and hence the writer would strongly commend the use of tubular or at least flue boilers in all cases. As the subject of burning wet spent tan, both in its eco- nomic and scientific relations to the tanner, is considered in a subsequent portion of this book, the subject may be dis- missed for the present with the statement, which seems nec- essary in this connection, that the spent tan can be so utilized as to give all the power required by the tanner in softening his dry hides, in grinding his bark, in rolling and finishing his leather, in warming his building, in heating his liquors, and in doing such other service as may be done by mechani- ical power. THE LEATHER MANUFACTURE. 149 The glue ^>iaok, of which every tanner has more or less, is vakia,b}6 almost in proportion to the care bestowed upon its preservation, and this is true without considering the higher grades of gelatine which are made from calves' pates and hot, and the sinews from neats animals. These are, or f.hould be, preserved by the slaughterer, and handed over to the manufacturer of gelatines for human food. In the preservation of tanners' hide offal, as it is known to come from ordinary dry and green hides and skins, it is of the first importance that the "glue" or "size" pieces should be sweet and pure from all " taint " or " smell." The paper makers use animal "size" very extensively, and such as they use must be absolutely free from all bad odors, otherwise the paper is rendered worthless. "With all the care which the paper makers exercise they do occasionally use "tauited" size, and the odor will cling to the paper forever, greatly less- ening if not entirely destroying its value. Next in import- ance to paper size comes the fine glues which are used in book and furniture work. In these, too, it is of great im- portance that there should be perfect purity and freedom from all smell. It is only for the most common use, such as preparing petroleum barrels, sizing woodwork, etc., that glue that has been in the least tainted can be used ; therefore it is that the value of this stock depends almost entirely upon the care taken in its preservation from all bad odors. "When the hides or stius are either fresh from the anim il or have been properly cured with salt there is no difficulty in avoiding all decomposition — indeed, nothing but absohite carelessness can bring harm to the "glue pieces." But if the pelts have been dried, and require to be softened before being Hmed or sweat, then it is that care and close and prompt attention should be given to the preservation of this valuable offal. Whether from green or dry stock, the trim- 150 THE LEATHER MANUFACTURE. mings slionld be thrown into a weak lime as soon as tliey leave the beam, and should be retained in this lime until the hair will almost drop off; when in this condition they should be thrown into a revolving wheel, or may be put in the hide mill, and worked until all the hair has been separated from the pieces. If a bountiful supply of water has been allowed to run on while the wheel or mill was in operation, all the hair will have been worked off and separated from the pieces, which will then have parted with so much of their lime as to make them, when dry, flinty and hard ; to avoid this they should be thrown back into the lime for a few days, and again " raised." Before they are taken out to dry they should be thoroughly washed. The drying should be in the open air, and if on a flat board surface then the pieces should be frequently turned. Care should be taken to wash off all the loose lime, so that the pieces may present an attractive, uniform white clean surface. When tliej^ are fully dried they should be pressed into uniform bales. Under no circum- stances should any tainted or damaged piece be allowed to go in the bale. Paper makers will use SLicli hide offal for sizing, and pay three or four cents per pound more for it than glue makers can afford to pa3^ Calfskin shanks and pates are worth more for this purpose than hide cuttings, and should always be kept separate. Until within a few years cattle and calves' hair have only been used for plastering purposes, and for this the harshness produced by the liming process rather added to tlian de- tracted from its value ; but more recently this hair, particu- larly the calves' hair, has been u^ed for cloth, carpets and felting, and for these purposes it is required to be soft, which necessitates freedom from lime. Probably it will be ulti- mately demonstrated that the hair from hides that are un- haired by sweating, so far as the length (as in winter and THE LEATHER MANUFACTURE. 151 spiing liides) will serve, is far superior to limed hair for this very reason. Millions of pounds of this valuable product, that should have at least gone on the "fertilizing heap," if its length had been too short for cloth or felting, have been washed down the streams. It is important to select the white hair from all other colors, as it is worth nearly or quite double the price of the general stock. This selection is not attended with much inconven- ience if done while the beam work is in progress. If the hide or skin is white, or mainly so, it should be thrown to the beam hand whose duty it is to unhair this color ; when he has re- moved all the white hair he passes the skin or hide to his companion, and so in turn they pass to him all their pelts that have any considerable amount of white hair. In this way a single beam hand accumulates at his beam all the white hair, and of course it can be easily dried and kept separate. The -cleansing of the hair from the lime is attended with little or no expense. Throughout Europe it is washed by hand, large splint baskets being used ; filling a basket about half full, an attendant, standing on the bank of a stream, plunges it in and lifts it up until the currents of water passing through carry off most of the lime. But in this country a vat with a false bottom is used to better effect. The vat is placed so as to command a bountiful supply of water, and it has a false bottom bored full of small holes — large enough to allow the lime water and small particles of lime to pass through, while retaining the hair. While the hair is covered with water, and is being plunged, the openings iu the bottom must be closed ; when the agitation of the contents is com- pleted, the plugs may be drawn from the bottom, and, prac- tically, the particles of lime having gone down below the false bottom, the hair wiU mat together, settle down and rest 152 THE LEATHEK MANUFACTURE. on the false bottom ; very little or none of the serviceable long hair will have passed out. This process of fi'ling, plung- ing and draining off may be repeated a dozen times during 'he day, and the hair will be fairly cleansed. If it is desira- b 3 to cleanse the fiber of the hair from the effects of the lime, warm water run on the last time, and allowed to remain for a short period, will greatly aid this result. This latter process will leave the hair much softer than if cleansed only with cold water. When it shall be established, as now seems pr I: able, that all calves' and cattle hair can be utilized in making coarse blankets, cheap carpets and felting, other methods for neutralizing the lime will come into vogue. Never until within the past few years has the hair from liides unhaired by sweating been saved. Whether the hair was long or short it has all been allowed to pass down the stream from the mills, or if saved from the beam it has, in exceptional cases, been used as a fertilizer. It is now de- monstrated that hair from such stock is more valuable for all the purposes above referred to than when limed, and when the long haired hides are milled by themselves the hair will always pay the labor of saving. For felting, all hair from hides unliaired by sweating, both long and short, is servicea- ble, and should never be wasted. The principal expense in saving hair heretofore has been in the drying. This is obviated by a very simple contrivance, as follows : Make a plank box eight or ten feet long, four to six feet wide, and say two feet high; under a false bottom run a net work of steam pipe; place the pipe midway be- tween the bottom and the latticed false bottom, so far dis- tant from. each that a broom may freely pass to clear out the ■ accumulating lime dust — and when thus prepared turn on tli!) exhaust steam from your nearest engine, allowing the steam to condense through this piping and under this false bottom. THE LEATHEE MANUFACTURE. 153 Hair may be thrown into this box to the depth of one foot, and will only require occasional stirring for an hour to make it thoroughly dry. In this way the hair may be dried ready for packmg, while occupying but a small room space and at an inconsiderable expenditure of labor. Hair may be packed for transportation in bales, pressed as hay is (indeed, hay packing machines may be used for the purpose), or in sacks made of burlaps, as wool is usually packed. If pressed in bales, refuse boards should be placed on the bottom and top, and the whole bound with wire, pre- cisely as hay is now brought to market. When thus packed, fully 500 pounds can be placed in a bale four feet square. The water from the soaks, as well as the exhausted lime and bate liquor (includmg the wash from the hide mills and beam house), should all be cnllected together in a capacious reservoir situated, below the level of the tannery foundation, so that all these valuable liquid manures may be brought together without the labor of elevating. This reservoir may be at any distance from the beam house ; indeed, it is far better to be removed a few hundred feet than close by. It should be capacious enough to hold not only the liquid refuse, but also all solids which come from the sweepiugs and scrapings of the beam house floor and drying lofts. So valuable are these washings that the writer has known a small tanner to fertilize a hundred acres by the refuse of a five thousand hide tannery. Old spent tan, fine chips or shavings, and even earth, maybe carted and thrown into this fertilizer reservoir, and allowed to absorb the ammonia, and then removed to the land, with great profit. A tanner with poor land about him, who allows his refuse liquids to run into the stream, is culpably thoughtless ; and yet such instances are numerous, notably so in the St ite of Maryland, where the writer has seen hundreds of loads of 154 THE LEATHER MANUFACTURE. the residuum of spent limes and bates piled up around tlie tannery. As the law forbade the tanner from throwing these objectionable substances into the stream, and as he owned no land, and was surrounded with shiftless farmers, large piles of the most valuable fertilizers remained to obstruct his way. The single tannery to which allusion is made could fertilize, if all liquid and solid matter of the beam house was distrib- uted, more than 400 acres of land. / CHAPTEE XVIII. TANNING MATEEIALS. riETERENT KINDS OF HEMLOCK BARK INFLUENCE OF SOIL AND CLIMATE ON THE QUALITY HEAVY AND LIGHT BAKK VARIETIES OF OAK BARK THE " SECOND GROWTH " BETTER THAN THE FIRST^ — GAMBIER ITS GROWTH AND PREPARATION FOR MARKET ITS COST COMPARED WITH THAT OF BARK— VALONIA, DIVI DIVI, MYRABOLAMS " SWEET FERN," ETC. On tlie American Continent, bark is tlie principal material for sole leather tanning, and altliougli many attempts have been made to supersede its use, they have for the most part failed. The reasons for these faihires are not very difficult to find, and should convince that large class of experimenters who rely upon " sweet fern," " salt," " alum," " terra japonica" and the like substitutes that the day is far distant when, in this country, any other substance than bark tannin will be successfully used for manufacturing leather. The tannin from hemlock bark, probably, tans eight-tenths of all the leather made in America, and notwithstanding the opinion entertained in England— and in this country too, by a few — that hemlock is inferior to oak, as a tanning material, the writer believes that, so far as the question is susceptible of demonstration, this opinion is erroneous. But to pass, for the present, from the consideration of the comparative merits of the manufactured article, and consider only the comparative cost and value of the bark as a tanning 156 THE LEATHER MANUFACTURF. material, it should first be stated that there are two kinds of hemlock — white and red — and although there is a gi eat difference in the timber of the two kinds, there is not much distinction in the tanning qualities of the bark. Some tanners think there is a dissimilarity in strength, and also in color, but the conceded difference between hemlock barks may be attributed to other causes than this difference of "species." Soil and climate we know influence the tanning qualities of all barks, and none more than the hemlock. All tanners know that hemlock bark from low, marshy ground, or the swales of the hills and mountains, is much thicker than from the high lands and mountains, and further, that a southern exposure produces more thrifty trees, and consequently thicker bark. The wash of the mountains, of course, feeds and enriches the valleys, giving richer soil and damper earth, both of which are indispensible to rank vegetable gi'owth. It may not be generally known that all barks, like all woods, are made up of distinct layers or deposits, one layer being formed each year. This formation takes its character from the soil and the season ; if in rich soil and damp, wet surroundings, the layers will be thick, and " fat" with tannin, but if other- wise, the layers will be thin, and the tannin "lean." So uni- form and unerring are the laws governing these deposits, that naturalists claim they can not only tell the exact age of the tree, but they can determine with considerable accuracy the nature of the seasons through which the life has progressed. Assuming then that tannin is deposited just in proportion as the growth of the bark or tree is rank and healthy, we can easily see how it happens that in some sections of the coun- try a cord of hemlock bark will weigh 1,600 to 1,800 pounds, and tan but 140 to 150 pounds of leather, while in other sections a cord will weigh 2,200 to 2,300 pounds, and tan 200 pounds of leather. These may be taken as extremes of qual- THE LEATHER MANUFACTURE. 157 ity, but to find these extremes one need not go out of the same neighborhood. The swamp bark represents the one extreme, and the high mountain bark, particularly if having a northern exposure, the other extreme ; and yet, while this difference is known to all well-informed tanners, they con- tinue to pay the same price for each kind, and wonder why one cannot tan as cheap as another. But there is a further con- sideration which weighs against the light bark, and it is this : the small, stunted growth bark will -curl, forming " gun bar- rels," while that from the heavy swamp timber will he flat. This fact goes, to some extent, to make up the great differ- ence between the cord of 1,600 pounds and that of 2,300 pounds, but the assumption of inferiority is outside and in- dependent of this disparity of measure ; if the premised are right, 2,000 pounds of heavy hemlock bark will tan more than 2,000 pounds of light hemlock. Practically the difference cannot be very great, but so long as tanners continue the unjust practice of buying bark by the cord, instead of the ton, they will do themselves this wrong. The writer knows of a location w^here, for many years, the competition for bark has been very strong ; but one tanner, appreciating the difference above referred to, has always selected and purchased the lots of heavy bark, paying from one to four shilhngs per cord more than his neighbors, by which means he has, probably, paid less for the actual tanning material than any of his com- petitors. Why should one bark peeler be required to rank and draw 2,300 pounds from six to ten miles for the same price that another gets for 1,600 pounds ? The injustice both to the tanner and bark peeler must be very apparent. The light hemlock bark is supposed to impart less coloring matter than the heavy. This is possibly true ; indeed, it is so in ths judgment of some of our best-informed Eastern tanners. Acting on this supposition, the fair leather tanners 158 THE LEATHEE MANUFACTUEE. of Connecticut and Massacliusetts continue to use the light hemlock obtained from the upper counties of Massachusetts and Yermont, supposing that the want of coloring matter will compensate them for the deficiency of strength. The beautiful lemon color produced bj the Connecticut and Mas- sachusetts sheepskin tanners may be the result of the loeok but ^ure liquors which they use, but if they subjected their bark to the same heating and JeacJmu/ process as that of our sole leather tanners, possibly the difference would not be as great as is now imagined. However this may be, the suj)- posed difference in the coloring matter of hemlock bark is keeping several large fair leather tanners in Connecticut from availing themselves of the cheaper hemlock of Pennsylvania and New York. To verify the theory here presented in regard to the quahty of bark, let the reflecting tanner pass over in his mind, as he readily may, the whole tanning region of the country, com- mencing with Maine, on the East. There we find a cold climate, and for the m.ost part a poor soil. The valleys of the Aroostook, the low lands surrounding Moosehead and other lakes, may be exceptions ; but generally these rich lands are covered with pine, and have only occasional patches of hemlock. The hemlock bark from that State is thin, and will not weigh, as bark is ordinarily measured at our tanneries, over 1,800 pounds to the cord. The same general character holds true of the bark of all the New England States. In the lower counties of the State of New York we have a warmer climate and a more diversified soil ; where the soil is favorable we have thick bark, but the hills and mountains give us much thin bark. This is true of Northern and Eastern Pennsylvania also ; but as we proceed West and South in New York and Pennsylvania, the country is more open and level, the soil richer, and we have a more uniform and much THE LEATHER MANTJFACTUEE. 159 thicker bark. Take those counties where wheat grows nat- urally, not merely on the river bottoms, but on the slopes of the highest hills and mountains — where you can see no " bar- ren wastes," as in Eastern and Central New York — and you are sure to find thrifty trees, with long bodies and thick bark - — bark that will weigh 2,200 to 2,300 pounds to the cord. The effect of soil and climate on the growth and strength is still more apparent in oak bark. The bark from this tree is comparatively worthless in a cold latitude, while in Lower Pennsylvania, Maryland and Virginia, it is strong. There it grows on the bottom lands ; this, with the warm climate, gives the rank growth. But in New York the oak grows only on the hills and ridges, being crowded out. from the swales by the hemlock, birch, beech, and maple, so that we cannot say what it might do under more favorable chcumstances. It was suggested by the late Col. Pratt, and has been re- remarked by other observers, that sea air has something to do with the strength of bark. This observation, confined to oak, certainly seems to be verified by the known facts, for the oak of Ohio, Michigan and the Western States generally is very weak — scarcely strong enough, as now used, to furnish liquors of sufficient strength to preserve the hide from putre- faction. But may it not be that the oak of those States is of a different kind from ours ? The writer has not seen rock oak there, but has seen white oak and red oak of im- mense size and growth. This white oak bark is a poor tan- ning material, and the red oak but little better — scarcely yielding enough tannin to pay for peehng. May it not be that the influence of sea air makes the difference between their oak and ours ? How many pounds of leather will a cord of hemlock bark make ? This question, a thousand times asked, has never been answered, and never can be, until a more certain rule of 160 THE LEATHER MAmJFACTUEE. measurement is determined upon. As already hinted, if in a new location, where strong competition does not compel the tanner to take 90 to 100 feet for a cord, but where he can get 128 soHd square feet, and that, too, of good, heavy bark (and the heavy bark is always peeled first, for obvious reasons), then 200 pounds of leather can be made from one cord of bark ; but if these conditions are otherwise, then from 130 to 150 pounds— and it is safe to say that throughout thfe o]d tanning districts of New York State 160 pounds is a full average. Little need be said of oak bark, for its merits are appre- ciated the world over. In this country we have the following kinds: Rock Oak, (called by some "chestnut oak;") Yello^v Oak (called sometimes " black oak," from the dark, black ex- terior, but by tanners called "yellow," from the fact that a very yellow color is produced by its bark ;) Jied Oak and WMte Oak. The first two are considered the most desirable. Their strength is about equal. The coloring matter, how- ever, of the yellow oak is so objectionable for sole leather that, unless used with red oak or hemlock, its value is very much impaired, but it is valuable for dyeing purposes, and is exported fi-om Philadelphia and Baltimore in large quantities, under the name of "quercitron bark." This bark (although of rather inferior quality) is found in large quantities in the State of New Jersey. WMte Oak makes a beautiful leather, but the tannin it con- tains is so small in amount as to render it almost worthless certainly not more than half as valuable as the better de- scriptions of oak. The coloring matter, too, although very good of itself, is too weak to be of much value as a dye. Bed Oak is a heavy, hard bark to manage— difficult to grind, and heavy to handle— and when leached or used as a "duster," produces a "mean" red color, without the "fresh THE LEATHER MANUFACTURE. 161 hue" of the hemlock, or the "true bloom" of the oak, and would seldom be used for its own sake — but the wood is val- uable for staves, and hence the bark is peeled, and finds its way to the tanner, and, to his detriment, he is often induced to use it. The original oak — that is, the first growth, even of the best descriptions, is quite inferior as a tanning material; but the second growth — the young trees, say from fifteen to twenty-five years old, particularly of the rock oak — ^is very valuable, and, when properly blended with hemlock, makes a leather which, for color and wear, wiU compare favorably with the best tannages of the world. The effect of age upon the oak tree is to cause it to throw o£f a dead ross, which loses its tanning quahties ; hence, until within a few years, it was customary with all our oak tanners to ross their bark — throwing away as worthless fully one- third the substance of the bark; but, after using up the old first growth, and coming down, as we now have, to the second growth, which has much less of this dead ross, the practice has gone into disuse. Oak trees reproduce themselves in about twenty to thirty yenrs, on good soil ; hence we may safely rely on a continu- ance of a supply. This circumstance, coupled with the favor with which mixed bark tannages are regarded, leaves no doubt that for all time we shall have a full supply of oak bark. Indeed, it has been estimated that more oak tannin is now on the trees of Ulster and Greene counties than there was twenty years ago. Although this reproducing quality does not belong to hemlock trees, yet, in such abu^dance are they, both in Kew York and Pennsylvania, that many hundred years must pass before they become extinct. The curing of oak bark is an important subject, and is but little understood— or, if understood, is but poorly attended 11 162 THE LEATHER MANUFACTUEE. to. Fully one-third of tlie strength is lost in the careless cure, exposure to wet weather, piling damp, etc. The English pay as much' attention to the cure of their bark as to that o.l their hay. The damage to oak bark, from improper exposure, is quite as ruinous as to hay, and yet our bark peelers give the bark only as much attention as their leisure will permit. The substitutes for hemlock and oak bark— the two prin- cipal agents used for tanning in this country— are very nu- merous. Gambler, or terra japonica, stands first and most prominent among the substitutes for bark, both in England and here. In 1840 the first "terra" was used in America, and only in small quantities, a few bales then sufficing to supply the market; now the import amounts to thousands of tons annu- ally, and its use extends to all the northern Atlantic cities, Newark, N. J., and Danvers, Mass., being the largest con- sumers. By a decision of the United States Treasury Department, gambler, catechu, cutch, and terra japonica, are all considered in commerce as essentially the same, but while they all come under the common name of terra japonica or gambler, a preparation of catechu, there are three different kinds of gambler, (in bales, cubes pressed, and cubes free), all of which differ in price from each other, and from what is known as cutch. The supply comes almost entirely from Singapore, in the East Indies, that island having become an entrepot in which are collected for exportation the pro- ductions of Cochin China, Siam, the Malayan peninsula, and the whole region of the Eastern Archipelago, from Sumatra to the meridian of New Guinea and the Phillipines. The product, as we receive it, is extracted from the leaves nf a species of acacia, those from different parts of India giving slight variations in the quality. The shrub, or bushy THE LEATHER MANUFACTUEE. 163 bree, is grown from slips or cuttings, on plantations. It is cultivated and manufactured on land leased from tlie various Rajahs. Tlie shrub is allowed to grow for the term of two or three years, till it attains the size of dwarf pear trees, when they commence to strip the leaves, stripping at all seasons of the year thereafter, for five or six years, until the soil is ex- hausted; the leaves come thickly on the long, drooping limbs, which grow outward and downward fi'om the gi-ound to the top. The leaf is in shape like the mulberry, but is thick and gummy to the touch. The production can be in- creased to any extent, and would, probably, if a long ruling of high prices should warrant it. The cost— the ground rent being nominal— is the labor, fuel and transportation, at the plantation not over Ic, to l|c. per pound. The leaves are boiled to extract the gambier ; when re- duced to the thickness of molasses the leaves are raked out, being used for a land dressing about the pepper trees ; the water is then evaporated from the gambier by placing it in pans and exposing them to the heat of the sun ; later, after drying the gambier in these pans, it is cut into squares, form- ing cubes, which, when dry enough to handle, are bagged, sent to market (Singapore), screwed into bales of 266 pounds, matted, covered with gunny, and is then ready for shipment. In the settiug out of the cuttings they are placed as near each other as will leave room for the shrub to grow. An acre will produce 2,600 pounds annually, but it soon runs out the soil ; years ago it was mostly produced on the island of Singapore, but now very little is raised there. There are f^everal kinds or qualities, the Ehio being the best ; it orig- inally came in baskets, in loose cubes, but lately.^ like the others, comes to market in bales. Cutch and gambier are from the same or similar trees, but the two do not come from the same part of the country. 1(34 THE LEATHER MANUFACTURE. Cut ch is extracted from wood of tlie larger and older trees ; these trees are not cultivated, but taken naturally, the heart cut out, and from that the article known as ci^tch is extracted. But to pass from the consideration of the source and man- ufacture of gambler, let us consider it as a substitute tor bark. In its pure state it is largely used for dyeing pur- poses. The color is so dark and unsightly that tanners can- not u«e it— unless with yellow oak— without leaving a very objectionable color. The strength of pure gambler has never been appreciated in this country, and, probably fi-om the consideration above presented In England, on the con- trary, where oak bark is used with a " strong bloom," the color is overcome. Let me say here to the tanners of our country that gambler, in all its varieties, is an expensive substitute for bark. Hem- lock bark at $10 per cord is as cheap as gambler at 31 cents per pound; and yet the Newark tanners, with bark at $9 to $12, are using gambler extensively, with the latter costmg from 5 to 7 cents a pound. The same may be said of the tanners of Danvers. Why this want of economy? Because gambler comes in a form very convenient for use— can usually be bought in any desired quantity, at any season of the year. Its use prevents overcompetition for bark, and as the tanners are not q2iite sure that it costs them more than bark, they keep on using it, on the principle they do much of their busi- ness, viz.: "All is well that ends well." There is a day in the future when all this blind waste must give place to true economy ; and when that day shall arrive, perhaps to be hastened by the substitution of extracts from the barks of our own forests, then shall competition from England be no longer feared by us, but free trade in leather, as in everything else, shall best serve our interests, as it would certainly best comport with our self-respect. THE LEATHER MANUFACTURE. 165 The exports of gambier from Singcipore for the past sixteen years have averaged, for each year, as follows : To Great Britain 15,818 tons. To the Continent 3,930 tons. To the United States 4,818 tons. According to these figures the amount taken by the United States has shown very little variation during the whole pe- riod. The amount used by Great Britain is supposed to be equivalent to about 60,000 cords of bark yearly. The price in London is now from <£25 to ^32 per ton. In Great Britain they have many other tanning agents for their heavy leathers, with which in this country we have so little experience that it would be presumptuous for the writer t ) speak particularly of them. They are mainly valonia, divi divi, myrabolams, etc. When the English tanner shall be- come as communicative as he is at present reticent, the Avhole world will be enlightened as to the comparative econ- omj of these agents with those in use with the t muers of the rest of the world. Valonia is the commercial name for the acorn cups of an Asiatic species of oak, which forms a very considerable article of export from the Morea and the Levant. The cup only forms the valonia, the acorn not being exported. While kept dry it presents a bright drab color ; exposure to dampness makes it black and destroys its tanning properties. It is very light and bulky, making the cost of its freightage high. It is very little used in the United States, but in England the imports are about 4,090 tons annually. The price in London is now from =£15 to £18 per ton. Divi divi is a pod of a shrub, a native of South America and the West India Islands, the tannin of which is concen- trated in the rind of the pod, immediately beneath the epi- dermis ; the inner portion, including the rind, is worthless 166 THE LEATHEE MANUFACTUEE. for tanning. The leather prepared with divi divi irj likely to be porous, and tinged with brown, or brownish red; but little of it is used in this country. Myraholams is the commercial name of the dried fruit of the ntdiiccanria, imported mainly from the East Indies. The imports at London for 1875 were 9,800 tons, against 11,200 tons iu 1874, and 4,100 tons m 1873. The present price is from X13 to £11 per ton. In addition to the above tanning materials — so la'-gsh' used in England, and in combination one with another as well as with bark— he English tanners also use considerable quan- tities of Mimosa, Belgium and Cork tree bark, and are yearly taking constantly -mcreasing quantities of our hemlock extracts. Sweet fern is a tanning shrub or plant found on the barrens of most of the counties in the Eastern States. It has been extensively used in England, and to a limited extent in this country. The writer has been reminded by frequent circu- lars of various patents granted for the use of this plant for tanning. After reading the strong array of certificates in favor of the excellent quality of leather made from " sweet fern," by postmasters and other equally good judges, he does not dare to question the value of such patents. There is one point, however, to which the attention of all experimenters on these substitutes should be called. The question is not whether you can make tough leather with " sweet fern," su- mac and the like, but whether you can make the same or better weight. Can you make the leather with tannin so that it will both resist fricHon and luater ? And more important than a'l, Avill the cost be less than with hemlock bark at $7 per cord, or good rock oak bark at $8 per cord or ton ? That leather can be made from sweet fern, sumac, birch, chestnut, willow — indeed, almost all barks— and that various THE LEATHEE MANUFACTUKE. 1G7 acids and salts will cure, or, if you please, ian leather, uo one at aU acquainted with the subject will dispute. Some of the toughest, best working calfskins that were ever produced in our market were tanned with birch bark, and the color, too, was good ; but they were tough because the bark liquor waft weak and the fiber, in consequence, elongated ; the weight and general plumpness were sacrificed to toughness. But when shoemakers, or even postmasters, certify that calfskins resist water better when tanned by these processes than when tanned by pure oak or hemlock bark, the writer is willing to believe them honest, but attributes a little of their zeal to kindness of heart rather than maturity of judgment. This subject is well illustrated by repeating a conversation held not long since with an old gentleman, who prided himself on knowing " a little about leather," as on other subjects he was wise. He said he always bought his calfskins of the " Shak- ers," for, said he, "they tan without steam," and "when my boots are made of their Hghtest calf, I can wade all winter through snow and water, and do not have even damp feet." The old gentleman meant to tell the truth, but probably he had not been in the snow and water without rubbers for years. Yet he succeeded in his purpose — he entered his protest against " steam tanning." It is thus that many peo- ple, from only a partial understanding of a subject, are free to give their opinions, upon which opinions too many, equally credulous, confide, to their cost. Many old-fashioned tanners, who have used only weak bark liquor, and for the first time tried terra, are astonished at the result. They tan as much in sixty days as by their old sys- tem they did in six months. The solution of the matter is plain ; they make a strong decoction of the terra, one that will stand 20 to 25 degrees by the barkometer ; whereas, by the old bark process, they were tryicg to tan with 6 or 8 degree 168 THE LEATHEB MANUFACTUEE. liquors. But let any tanner take one hundred pounds of terra and dissolve in the usual way, and then take the strength of one cord of good oak or hemlock bark, and he will find the latter will tan double the quantity of leather that the former will. In this chapter the tanning agents employed in tawing or tanning light leathers have not been considered. The omis- sion has been made designedly, for the tanning and tawing of light leathers is a trade by itself, the treatment of which is not within the scope of the present treatise. CHAPTEE XIX. THE COST OF TANNING. THE SEVERAL ITEMS VARYING WITH DIFFERENT TANNERS DIFFERENCES FROM UNEQUAL WEIGHT OF THE CORD OF BARK THE AMOUNT OF TANNIN IN UPPER LEATHER AS COMPARED WITH THAT IN SOLE LEATHER COMPARATIVE COST IN MAKING HEAVY AND LIGHT GAINS THE THEORETICAL STRENGTH OF BARK NEVER REALIZED COST OF " UNION " AND OAK TANNING ESTIMATED COST OP TANNING IN EUROPE. Approximately, tlie cost of tanning is as follows : Hemlock sweat sole leather ft) 6@ 7c. Union lime sole leather 8@ 9c. Oak lime sole leather. 9@10c. Oak lime rough leather 8@ 9c. Hemlock lime rough leather 6@ 7c. The varying circumstances under which the tanners' pro- fession is pursued will cause the cost to differ within the hmits above indicated. When a closer estimate is desired, giving the cost of each department, then a great diversity of opinion prevails. One tanner devotes extra time to the beam- house work ; another to the finishing ; still another to the handlers or layaways. If bark is cheap at one location, in- land freight and cartage is in excess of that at another place 170 THE LEATHER MANUFACTURr. wliere bark is dearer ; therefore, in stating the elements of cost, it is understood that an average is struck. These at- tem23ted details are of far less value than the general conclu- sions, which may be relied upon as above stated. One ton (2,240 pounds) of average hemlock bark will tan 200 pounds of sole leather. Some of the exceptions are as follows: 1st. Where the bark is ground and leached imper- fectly, or in an extraordinarily perfect manner. 2d. If the leather is tanned with very strong decoctions, and thereby a very large gain is obtained, as against weak liquors and a light gain. 3d. Great delays and wastes in applying the tannin to the leather — delays which induce the formation of gallic acid, or the bringing of the fresh, sweet, strong decoc- tions into contact with liquor which has already formed a large proportion of acid. These exceptions cannot be always anticipated or known ; it is safe to say, however, that they vary the result all the way from 180 to 200 pounds of leather made from one cord or ton of bark. If tanners buy their bark by the cord, and get less than 128 feet solid measure — resulting, as often hap- pens, in getting 1,800 pounds, instead of 2,240 pounds for a cord — then, of course, such tanners will find the results of their tanning to vary still more. Among the topics above suggested there is but one to which attention will be now specially called, since on that one depends, far more than is generally supposed, the profit or loss of the tanner, i. e., the strength of the liquor employed. The upper leather tanners of New England, who pay from $10 to 112 per cord for their bark, claim to tan and probably do tan from 300 to 400 pounds of upper leather with 2,240 pounds of bark. If we comprehend how this is possible, it will enlighten us as to the point under discussion. The up< per leather tanners draw their tanning and coloring matter THE LEATHER MANTJEACTURE. 171 from agents wliich furnisli about 20 per cent, extractive ma- terial, while the vigorous sole leather tanner obtains his cap- ital mostly from the 7 to 8 per cent., tannin which the bark contains. The tannin , gives aU the gain added to the gela- tine, but the coloring matter permeates the fiber, while cumu- lative gallic acid holds it from decomposition. Upper leather, then, is not tanned and filled as sole leather is, and to this ex- tent, and for this reason, bark extract will spread itself over far more fiber when all the extractive mattej- is employed, than when it is so manufactured as to hold only the tannin pure and simple. The calfskin and upper leather tanners of Germany, Aus- tria and Switzerland make fully 400 pounds of rough stock from a ton of tlio best coppice oak bark, and where they use the " larch," corresponding? to our " spruce " bark, they prob- ably >make about 200 pounds (this bark having less than half the strength of the former). If upper leather and calfskins are to be sold by the pound (waiving the question of quality, especially toughness), then it is evident that these light tannages cannot be afforded. But if sold by measure, then a light tannage is profitable for both the tanner and the consumer, under proper circum- stances. It is not proposed here to discuss the question wliether a light tannage will resist water. A tannage with an elongated and merely colored fiber will not carry stuffing when curried into upper, and will not resist dampness, and for these reasons such leather should not be used for the common wear of the people, whose feet are exposed to the varying conditions of the weather in our moist and wet cli- mate. This preliminary discussion has been intr )d iced to solve the question as to wliether a sole leather tanner who tans by the pound, and is not interested iu the question of interest, 172 THE LEATHER MANUFACTURE. can afford to make lieavj gains for his employer. One tan- ner makes 160 pounds and another 175 pounds of leather from 100 pounds of the same description of hides ; are they entitled to the same pay per pound? Is the cost to each pro- portionate? The argument on the one side is as follows : It costs a certain sum to work in, handle and finish a given lot leather, whether of a heavy or a light tannage ; the cost of the bark being alone considered, it cannot exceed and most usually falls short of the price received for tanning, even though that price is as low as six cents per pound. The sole leather problem is, then, in fact, but the upper leather question over again, which would ask and determine the following: Can a tanner afford to tan rough leather for less per pound than sole leather, less the finishing? It is no answer to say they do tati it for less, and it is not convincing that small yards in old tanoing districts, without mucli in- terest to pay, are still pursuing this trade successfully. The argument on the other side is that heavy gains cannot be made without strong liquors; strong decoctions cannot be obtained unless more or less waste is permitted — waste in the liquor itself, and more strength lost in leaching. Besides, the actual net added weight costs more than is received, which is calculated as follows : Original weight of hides 100 pounds. Less hair, grease, flesh, etc 15 pounds. Net gelatme and animal fiber 85 pounds. Now, whether this product is raised to 160 or 175 pounds is a question of mere intrinsic cost of the pure tannin which is capahle of combining with the gelaiinc In the one case 75 pounds is required, and in the other 90 pounds. The cost of these resp: ctive factors made from bark at $6 per cord would be (on the theory on which we are proceeding) fully 8 cents per pound, since in both cases w^e start with the hide capital THE LEATHER MANUFACTURE. 173 of 85 pounds. It may be assumed that tHere is a discrep- ancy between tlie theoretical and practical percentage of tannin obtainable from bark. We know that 2,240 pounds of hemlock bark will make only 200 pounds of leather. Chemists tell us, however, that there is 8 per cent, tannin in this bark ; consequently there is in this ton of bark 156 80-100 pounds, which, combined with 85 pounds of gelatine, should give 241 80-100 pounds of leather. What has become of this 71 pounds of lost tannin? When any tanner will practically solve this doubt, then, and not until then, will the main question be answered. Practically, the cost of a pound of tarmin is from 6 to 8 cents, and not 3 to 4 cents, as is gen- erally supposed. ^. There is another subject nearly allied to the cost of bark, and that is the intrinsic cost of the oil put on sole leather. If the oil added gave full weight, then it could easily be de- termined wliether it was profitable for the tanner to put on much or litt'e oil. But, like the tannin just considered, there is much evaporation and loss, and the extent of interest in the final result of weight and profits must determine whether the tanner can afford to put oil on his sole leather at all, and to what extent. The cost of administration in a tanning estabhshment is always underestimated, and from this source, in the writer's judgment, many of the discrepancies result. A story is told of a young man who left his father's home to reside in the city of New York, promising to keep an accurate account of his expenses, and, with all his care, he found himself over- drawn more than $100 at the end of the year. To the m- quiry from his father as to the cause of this discrepancy, he said it must be " litterateur." The incidental expenses of a tanning establishment are not less difficult to define. If an attempt were made to properly apportion each item of ex- 174 THE LEATHER MANUFACTURE. pense in the production of leather, the factors of the total cost would be about as follows : Cost of bark (hemlock) per ft .' Sc. Cost of soaking, milling, sweating and beam work . . Ic. Yard work, including handling, laying away, etc ic. rinishing, including drying, rolling, etc ic. Insurance, interest on tanning and bark ic. Freights to and from the market Ic. Administration in ■• • • 2*^' Total The cost of union or pure oak tanning will vary consid- erably from that of hemlock tanning where the hides are un- haired by sweating, for, besides the added cost of bark, the extra care throughout the whole process, including the labor expended in the preparation of the hides, that are mostly green or green salted, will make up the difference, and the cost of the several kinds may be considered as stated at the head of this chapter. After the most diligent inquiry the writer has found it im- possible to even approximate the cost of tanning in the prin- cipal nations of Europe. A London tanner in 1873 estimated his tanning to cost 12 cents per pound in bark, and 10 cents per pound in terra japonioa and valonia, but confessed that it was only an estimate. More recently a Bristol tanner cal- culated the cost of his pure bark tanning at 15 cents per pound, and even this is probably only an estimate. The cost of coppice* oak bark in the most favored locations is not less than $25, gold ; and in most sections of Europe it runs up to $30, and even $40, per ton. On light tannages no doubt this bark will go a great way, but on butts and bends it may be assumed that foreign tanners use liquors * " Coppice " bark is from small trees, too small for timber, say six to eight inches in diameter ; also from Umbs, equal to our " second growth " bark. THE LEATHER MANUFACTUEE. J-'O f)f tlie highest strength. This is particularly true of the tan- ners of Great Britain ; perhaps it is not true to the same ex- tent of tanners on the Continent of Europe. The cost of all other material, including labor, is not greatly different in Europe from the cost here. The tanners of Great Britain pay about $1 per day for their average hands, while in other countries they pay, according to a re- cent authority, about 80 cents. But it may be fairly ques- tioned whether our labor is not more effective, especially in view of the increased amount of labor-saving machinery which we employ over some, if not all of our competitors. CHAPTEE XX. QUICK TANNING PROCESSES. COMMON EBROES OF THOSE OUTSIDE OE THE TRADE HOW WOBTHLESS PAT- ENTS AEE MULTIPLIED — EXPERIMENT IN TANNING BY HYDROSTATIC PRESSURE— VACUUM TANNING— DIFFICULTIES ATTENDING THIS METH- OD—HOW AGITATION OF THE FIBER FACILITATES THE PROCESS— A GENTLE MOVEMENT, WITH OCCASIONAL REST, MOST EFFICACIOUS TANNING VS. TAWING. It is noticeable that most of the attempts to substitute new for old methods of tanning are made by men outside of the trade. Very few of the new inventions for tanning, particu- larly those that contemplate the saving of time, originate withiii^the trade itself. The inspiration of all this solicitude on the part of the outside world seems to come from the idea that tanning is a slow and tedious process, which needs in- vigoration by the genius of inventors and men of thou-rht. They have "read history," in which it is claimed that seven years is the allotted time to tan butts and bends and make good leather, and that in this country we have only improved on this time by the introduction of "steam" and other " forcing expedients," which render the leather products here much less valuable than in Great Britain. There is do topic which requires more vigorous treatment than this, not only for the good of the trade, but for the ben- efit of that large and unfortunately increasing class of men who desire to get a living by their wits and without labor. THE LEATHEE MANUFACTURE. 177 As it is now our Patent Office gives encouragement to this class of parasites, for there seems to be no claim for im- provement too absurd to receive favor, and patents are mul- tipHed to such an extent that no man can keep an account of them. There are at present more than twenty patents for unhairing hides with alkalies, when the process of taking off the wool from the sheep and the hair from the deerskin by ha> d wood ashes is older than our civilization. What is most urgently needed in our Patent Office is at least one Examiner that has practical knowledge of the tanner's art. Such a se- lection it is not unreasonable to ask, when it is considered that this manufacture stands second in importance among the industries of the country. Proper discrimination would greatly aid improvements, while our present system confuses and retards meritorious inventions. Among attempts to facilitate the tanning of leather, per- haps no method or device has been more seductive than the forcing process known as the " vacuum " method. It is be- cause of its specious character that attention is here given to the details of its history and failure. Hydrostatic power gave birth to the first idea of tanning by pressure. " If," said a student at school, "I can raise myself with one quart of water, by means of a hydrostatic bellows, that principle can be availed of to force tannin into the pores of a green hide," and so the experiment was tried, in the following manner : A keg of very strong construction was procured, and a tin tube one inch in diameter was run up through the lofts of a tan- nery to the hight of thirty feet; the keg was filled with strong tan liquor, after a green prepared calfskin had first been placed in it, and then the tube was screwed on to the socket and also filled with liquor. The young tanner student had the satisfaction of seeing the liquor forced through the joints of the keg, and finally the keg itseK burst, by the hydraulic 12 178 THE LEATHER MANTJFACTtJEF, pressure caused by this small tube. When, however, the keg was burst open, the sldn was found to be only colored, and the fiber no more permeated by the tannin than it would have been if the skin had been thrown into an ordinary vat of liquor for the same length of time. This experiment was repeated several times, for a longer period in each case, by applying the power more gradually ; but the result each time Avas the same. Tan could not be forced into the pores of the skin by surrounding it with liquor under heavy hydrostatic pressure. The next experiment tried by this young student was to take a piece of prepared hide and place it under the exhaust pump. He had seen eggs expand and burst in a receiver, on exhausting the air which surrounded them. He had seen meat and dead animals expand and swell almost to bursting under a similar operation, and so, he reasoned, if he could place a hide in that condition, and produce that effect, and could, at the moment of the expansion, let in tan Hquor— the result must be to force the hquor into the most interior cell of the hide, and, as^ Sir Humphrey Davy had demonstrated that tannin and gelatine, when brought into contact, would both mechanically and chemically unite, he reasoned that such process of exhaustion of the air and swelling of the fiber must result in immediately tanning the hide, on the admission of the tan liquor. But such was not the result. The hide did not swell like other animal substances filled with air. He found that the cells of the hide were filled with water, and that water would not expand in any perceptible degree on account of the exhaustion of the air- A few years later an English engineer, who had through many years of his professional life practiced the art of pre- serving wood by kyanizing with appropriate chemical agents, conceived the idea of coming to this country and tanning THE LEATHEK MANUFACTURE. 179 leather on this Vacuum or kyanizing principle. He spent his entire accumulations, amounting to over $10,000, in con- structing a large iron tank in the shape of an egg, and lined this vat with copper. This tank was capable of holding one hundred heavy butts, and of resisting a pressure of one hun- dred pounds to the square inch. He provided himself with very substantial pumps to exhaust from this tank all the air, even to the extent of making almost a perfect vacuum, and other pumps to force in liquor, until he had obtained a pres- sure of 100 pounds to the square inch. Between these butts he had placed cocoa matting, so that there should be a per- fect circulation of liquor. In short, he prepared himself with every facility which money could procure to tan butts in a large and practical way by the exhaust or vacuum pro- cess, and after repeated attempts he failed entirely. What induced him to abandon his cherished enterprise was a small incident, which may throw light upon the subject for the benefit of those who yet see, or think they see, a defect in his method. In placing his butts in this egg-shaped vat, he f(Uind a space at the top which he could not fill with leather, and he placed there several blocks of seasoned wood, one foot square. When his experiment had ended and failed, after many anxious hours and days of trial, he found the wood perfectly saturated and tanned, but his butts were only col- ored through the grain. His conclusion was that the force that will kyanize wood will not tan leather. The name of the engineer was Thomas T. Ferguson, and the place where the experiment was tried was Sparrow- bush, Orange County, N. Y. The full details of the experi- ment were published in the Shoe and Leather Reporteh some years since, it having been made about the year 1855. Mr. Ferguson obtained patents in Great Britain and France, and applied for a patent here, but was so discouraged by 180 THE LEATHEE MANUFACTUKE. this eifort as to abandon all further attempts at quick tan- ning. After these experiments had been tried and published to the world there came another experimenter, this time with an indorsement of a patent, by which leather was to be tanned in wooden tanks or vats that were far inferior, both in strength and construction, to the plan of the English en- gineer just mentioned, and many tanners have been induced to invest in the new process. So far as is known, however, the new quick tanning process has been a failure, and it stands so confessed by those most interested. The rationate of this whole matter of tanning by pressure from both surfaces has heretofore been greatly misunder- stood. The term "both surfaces" is used, for it is conceded that if force is applied to one side, and that the flesh side, the tan liquor will very readily pass, and tan the fiber with T/hich it comes into contact. This is notably shown in the tanning of morocco and light leathers generally. A goat or sheep skin sewed up and filled with tan liquor will, b}' the gentle pressure of its own weight, tan in a few hours. A calfskin sewed up and placed where the keg was placed in the student's first experiment will tan in a few moments — that is, tan liquor will be forced through the skin, and the whole fiber will become colored, and even tanned. But it must be acknowledged that this pressure from one side is quite a dif- ferent thing from equal pressure from both sides at the same moment. Water or fluids of some kind fill the pores of the skin or hide, and these are not compressible, and in this lies the solution of these repeated failures. Water may be expanded by heat, but it cannot be perceptibly compressed by mechanical force or power. What would be the effect of forcing tan liquor from both surfaces into a hide that had no moisture or water in its THE LEATHEK MANUFACTURE. 181 fiber ? Simply to " tan in " just so far as there was tannin to combine with the gelatine, while the water in the hquor would pass on and fill the inner portion of the hide ; and then, before the process could be repeated, this water would be required to be pressed out by mechanical power or dried out by exposure to the atmosphere — and this alternate dry- ing and pressing process would be so tedious and withal so disturbing to the fiber that it would prove impracticable. It is not claimed here that under the recent vacuum pro- cess, so called, quicker time has not been made than by the older methods. The more frequent renewals of the liquors, the greater activity in handling, the agitation of the fiber occasioned by the alternate pumping out of the air and forcing in the liquors— these causes would naturally shorten the pro- cess, and are in themselves quite sufficient to account for the more rapid action of the tannin in combining with the gela- tine of the hide. But if, notwithstanding these experiments and warnings, tanners will insist on paying their money for patents that are worthless, no one should be held responsible, but our lunatic asylums should be enlarged. The supplement to lire's Dictionary of Arts and Manufac- tures, at page 1044, contains an account of an invention for tanning in vacuo, patented by M. Knoederer, in Bavaria, which should be read by all persons contemplating further efforts to avail themselves of this vacuo principle in tanning. The account, apparently, is simply a statement made by the patentee as to his claim, and the results. There is nothing in either that is worthy of serious consideration, except fi-om the fact that the account has a prominent position in a work of very high authority on general mechanical subjects, and for this reason it attracts attention. It is noticeable that in this process the sides or skins are passed under a mechani- cal press before they are put into the vacuo vessel. In this .182 THE LEATHEK MANUFACTURE. manner of preparing the stock, concession is made to the fact that water cannot be compressed. The writer has not desired to inveigh against the process of tanning by vacnum. If he had wished to show the com- parative expense of this method he would have gone into a calculation of the cost of the vats and machinery necessaiy to carry on such a system, giving the experience of some of those who have tried it — which shows that the vats made of plank and timber, and exposed to the air on their whole in- ternal and external surface, will decay in three years to such an extent as to require renewal — and so far as is known most of those who have tried the process have not renewed their vats after the first set has given out. One of the most noticeable defects of vacuum tanning is one that has been experienced in tanning by suspension in the ordinary open vats. The leather is " baggy " — that is, the nerve of the hide is tanned in its normal condition, and the shape of the animal from which the hide or skin was taken is approximately preserved. To overcome this defect it has been the custom of ihose tanners who tanned sole leather by this method to take the sides out of the vacuum vat and lay them away in the ordinary manner for a month or more. Whether sole leather is tanned by suspension in a vacuum or oidinary vat, the experience is that a much finer offal is produced than results from the ordinary handling and laving away. But the leather is neither so plump nor free from " bag " as if tanned in the usual way. It is claimed that ordinary slaughter sole leather, weighing eighteen pounds per side, can be struck through in fi'om fif- teen to twenty days, if vigorously attended to, under the vacuum i)rocess. The le.ither is then taken out and laid away for thirty or forty days, when it is ready to finish. In THE LEATHER MANUFACTURE. 183 making tliis statement, and conceding all that is liere claimed, what is the gain, either in time or quality? In ordinary tan- ning a daily strengthening and handling will bring this same leather through in sixty d-iys, without the violent agitation an l exjjense attending this foicing process, and with better color and plumper fiber. The innovations upon old methods of tanning take upon themselves two general forms. They are either physical Hud outward, or chemical and latent. Of the former, pressure, either with or without the aid of the vacuo principle, has the greatest number of advocates. All, or nearly all, the chemi- cal agents employed in the shortening of the process turn out to be the old methods of tawing ratlier than tanning. It is noticeable that even the vacuo principle is gi-eatly aided by the agitation of the fiber, for, by reference to the ex- periments of Knoederer, it will be seen that he tanned in about one-half the time when the leather was agitated in the vacuo vessel, over and above the time taken when there was nothing but the force of the vacuum to hasten the ]>rocess. The results are reported as follows : Time required for Time required taiminp; in vacuo when ]i\otioii without motion. is eniploj'ed. Calfskins . , from 6 to 11 days. 4 to 7 days. Horse hides .35 to 40 days. 14 to 18 days. Light cow. 30 to 35 days. 12 to 16 days. Cow hides, middling. . .40 to 45 days. 18 to 20 days. Heavy cow hides 50 to 60 days. 22 to 30 days. Ox hides, light 50 to 60 days. 20 to 30 days. Ox hides, heavy 70 to 90 days 35 to 40 days. Thus it will be perceived that motion or agitation of the fiber is a most essential promoter of quick tanning, even in vacuo. To this fundamental proposition all tanners can readily assent. When the advantages of motion or force, in the sense of agitation of the fiber, are taken from the various 184 THE LEATHEK MANOTACTIJRE. patents wliicli attempt to quicken the process of tanning, it will be found that there is very httle left that has merit. The writer once tried the following experiment : He took four veal calfskins, which weighed eight pounds when green, and prepared them for the liquor in the usual way. He then tied the skins together and suspended them from the end of a spring pole, so adjusted that they were covered all the time by the liqjior in the vat. For the first few hours the skins were agitated by means of this spring pole in a weak color- ing liquor, and were thus progressed from vat to vat until, at the end of the first day, they had reached a liquor of 16 degrees strength. At the end of four days they were fairly and even fully tanned. This spring pole was so adjusted that a slight touch of the hand would set it in motion, and as each one who passed had instructions to "lend a hand," the pole was kept in motion almost constantly, with the re- sult indicated. This experiment should be tried by every tanner. It will attract his attention to a most important ele- ment in quick tanning. If the experment should prove as interesting as it did with the writer, it will lead to other re- sults and conclusions. It w'ill indicate that a most delicate touch will agitate sensibly the fiber throughout the whole skin or hide; that gentle motion is most efficacious, and that violent motion is positively injurious, as the latter purges the cells of their gelatine and prevents the plumping and fin;)! gain in weight. The relative influence of gentle and violent motion on lea- ther when in the handlers has been demonstrated by the ac- tion of the " rocker." Here, with the most delicate ar^d uni- form motion, it is found expedient to discontinue the move- ment altogether for a considerable portion of the time, other- wise the sides do not plump and take on a uniform grain, whereas by only sufficient worlung the most desirable result THE LEATHER MANUFACTURE. 185 in these particulars is obtained. Many mistakes have been made, and much damage done through a misunderstanding of the action of liquor on the fiber, according to this princi- ple. Fifteen or twenty lifts or turns per minute are ample, and these should be continued only about half the time. Besides giving rest to the fiber, this slow motion does not, to the same extent that a quick, violent motion does, turn up the liquor, bringing it into contact with the air, thus causing gallic acid to form. These experiments, if carefully made, will also convince the tanner that the gelatine of the hide has such an afiinity for the tannin that they combine much more readily than is supposed ; this is made apparent by the rapidity with which the tannin is taken up while in the rocker vats. Once let a tanner be satisfied that his green stock is hungiy — constant- ly demanding nourishment — ^but without the voice to make known its wants, and his financial sympathies will hardly ever allow him to sleep without the apprehension that he is neglecting his most vital interests. Knoederer claims, and with some show of reason, that his vacuo process prevents the formation of gallic acid, and to this extent all methods that tan under liquor, in such manner as 'to avoid exposure to the air, either of the liquor itself or of the pelts that are in the process, should receive favor. Further than this, the method of "throwiog up" the packs, it is claimed, presses out the spent liquor and prepares the vacant cells to receive an infusion of newly charged tan liquor. Aside from the disproportionate labor imposed by the old over the newer methods, the writer believes that the action of the atmosphere, both on the color of the leather and to cause oxidation of the liquoi*', must prove a sufficient demonstration of its impolicy. Leather tanned while in a composed state (at rest) will •lO^ THE LEATHER MANUFACTURE. liave a firmer texture than if motion is used to aid the tnn^ ning. This would probably be the testimony of the butt and bend tanners of Great Britain, and there is much in our own experience to confirm such a view of the case. But the ques- tion under review is one rather of time than of firmness of texture. None of the advocates of improved forcing methods ckiUi, so far as the writer is aware, that they make firmer leather. They usually assume to make better time, and ex- ceptionally claim better gains. Their improved g iius they estimate to come from the saving of the waste of tlie gelatine, by reason of its earher entering into combination with the tannin by their quick as against the older and slower methods. The best exporieuce in America would direct that, after the hide is "struck through" by the most rapid combination possi- ble, it be "laid away" for a period .^f weeks and even months — all the time in which its firmness of texture will improve. But if it is only required to taw (that is, strike through) the fiber with tannin and coloring matter, then the handling or fiber agitating methods are ahke ; for harness, upper and even calfskins this process gives very fine offal, and makes most serviceable wearing leather. Hardly a month passes that some restive spirit does not discover, for the hundredth time, that salt and some of the sulphates, notably the sulphate of alumina, known in com- merce as alum, and potassa, will in various combinations tan, or, more properly speaking, taw or preserve, hides and skins, which, after being "mooned," will make a very tough and serviceable upper leather. In this manner glove and calf-kid leather is made in a most artistic manner, and on the Continent of Europe the latter description of lea 'her enters very largely into the consumption of the people for wear in shoes of both men and women. For dry and warm cHmates hardly anything more desirable could be obtained, and as it THE LEATHER MANUFACTURE. 187 is made at mucli less cost than bark tanned leather, tliere is an excellent reason why the calf, goat and sheep skins of those countries should be so manufactured ; but when these tawmg processes are applied to making sole leather in this country, wdiich abounds in bark, the tannic acid of which combines with gelatine, and is when so combined not soluble in water, then all effort in that direction is just so much wasted force. CHAPTEE XXI. THE SPECIES AND GEOWTH OF HIDES. " HKALTHY " AND " WELL GEOWN " HIDES — ^DIFFERENCES IN HIDES AT VA- EIOUS SEASONS OF THE YEAR— EFFECT OF CLIMATE AND FOOD ON TEX- TURE AND GROWTH IMPROVED BREEDS OF CATTLE MAKE HIDES THIN AND SPREADY COLD CLIMATE MAKES A COARSE FIBER AND WARM CLI- MATE A FINE TEXTURE EAST INDIAN, AFRICAN AND SOUTH AMERICAN HIDES TH*; HIDES FROM THE EASTERN AND MIDDLE STATES AS COM- PARED WITH THOSE FROM THE WESTERN PRAIRIES CARE TAKEN OF CATTLE IN EUROPE. In a previous chapter reference was made to the structure of hides, but for quite a different purpose from that which in- duces the treatment of this subject here. The bison, the sheep, the deer and the goat belong to species so different from the ordinary neat cattle that no one would think of comparing their merits or defects, although the designation of " growth " wdi apply to all alike. A sheepskin can be a "healthy pelt" and "well grown" no less than the hide of the ox or cow. In this chapter, then, will be considered the species of cattle and their growth, in the sense in which we speak of health in the animal and vegetable world ; not that aU animals or vegetables are alike, but only that they have their distinctive natures, and are well or id within those limits, according to the seasons and circumstances through which they pass. The English tanner must be credited wdth the first appli- cation of the term "growth" as applied to hides. He would THE LEATHEE MANUFACTURE. 189 formerly have said a hide is "well grown" when it was healthy, plump and fine — whether it was a bison hide from the Western plains of North America, or a Spanish ox hide from the pampas of South America ; but from this original and more correct designation the English tanner has come of late to speak only of plump, thick hides as well grown, and, as the term is thus used, only such hides as are suitable for butts and bends are called " well grown hides " in England. But, to use the term in a less restricted sense, the hide is well grown in the American tanner's view when it takes on its highest and most perfect nature, and then the designation applies to all hides and skins alike. We have spring, summer, fall and winter hides, and these adjectives haA^e to the tanner a most distinct and qualifying meaning. The hides of all our neat cattle in the spring of the year are thin, and frequently have grub holes in tha shoulder and on the line of the backbone. In early sum- mer the cattle begin to recover, and by late in June they have shed their hair, though while the hide is healthy the full growth does not come to it until September and October. The hides taken off at the latter season are thicker and healthier than those furnished at any other period. At the approach of cold weather the hair becomes long, and the hide, by sudden contractions and expansions, loses that firm- ness so desirable for butts and bends. The influences, also, of climate and food, quite independent of the health of the animal, have a controlling effect in de- termining the value of the hide. As an illustration of the effect of climate on the fiber, the hides from Cauada and from Russia are far coarser in texture, and for this reason are less valuable, than hides from the United States. Their winters are longer and much more severe than with us. This is true even when the cattle are the same in species. It is 190 THE LEATHER MANUFACTURE. for this reason, and from this cause in part, that the Spanish hides of South America are better grown, both in the Eng- hsh and American sense, than are the hides of our States. The extremes of weather we have are never experienced there. The cattle feed on evergreen pastures, and are never housed, as with us. The cattle of Texas are of precisely the same species, and even of the same breed, as those of Buenos Ayres, and yet, intermediate between these, we have the cattle of the Eio Grande, of the same species but of a different breed, whose texture is far coarser, showing that climate and food cannot wholly control the structure. The improved breeds of cattle which have been introduced both in Europe and here have done just so much to make the hides thin and spready. The improvement induces a thin skin. A "blooded horse" has a thinner skin than the old farm or plow animal. So noticeable is this that the English tanner has long since given up the idea of getting butt hides from domestic cattle. The cattle of Spain and Portugal, be- ing of the unimproved original stock, give the English tanners the only slaughter butt hides they have. In this country we are fast improving all the plumpness out of our hides, and it will be only a few years until we, too, shall depend upon Tex- as aod South America for all our thick pelts. If a cold climate induces a coarse fiber, then it should be true that a warm climate makes a fine texture, and this we find to be in accordance with the fact. The hides of Africa and Central America have a fine texture beyond any other of which we have knowledge. The texture is not seemingly so much affected by food as by climate. The great droughts of these tropical regions do not to any perceptible extent control the texture, but they do affect the growth. This is illustrated by the conceded fact that the cattle of Texas that THE LEATHER MANUFACTURE. 191 are known to die of starvation retain a fine textured hide. If it be said tliat the animal died before it had time to change the fiber or texture of its hide, this is not true of the growth, for the hide contracts and becomes diseased with the decay of the body. The same is true of a murrain calf or Idp skin. The fiber is really closer and finer than that of a vealskin. It is, then, probably true that where the species and breeds of cattle are the same, food affects the growth and chmate the texture, and the experience of those who should be the best judges confirms this conclusion. The " East " and " West Coast" African hides are so radi- cally different that it may be assumed the East const hides are from cattle brought from the Island of Madagascar, and still more remotely from Hindostan and the Chinese Empire. The hides from the West coast, bordering on the Atlantic, are substantially the same as those from our cattle, only dwarfed by imperfect food and culture. Australia, on the other hand, shows more direct signs of contact with Great Britain, whose colony she is. The cattle and hides from this province, although produced under the same climate as that of many other islands of the Indian Ocean, are distmct in character from all the rest, and when made into leather may pass for the hides of well grown neat cattle, equal to those of Great Britain or the United States. But the hides from the smaller groups of islands 'lying in the same ocean, as well as from China and Japan, are for the most part from cattle that are popularly known as East India cattle, so small in frame and delicate in outline, as compared with our cattle, a^, to have received the designation of "kips" rather than hides from full grown cattle, as they are. This designation covers that large class of East India kips from which British tanners make a most serviceable hght upper leather, and the imports of these kips at London and Liverpool amount to 192 THE LEATHER MANUFACTURF. about five millions yearlv. The cattle from which these hides are taken are quite uniform, and when full grown about the size of our yearlings, but are much more delicate in limb and feature. The part which this East India hide product is to play in the future supply of the world is as problematical as the question which is now agitating our country about the labor supply from that quarter. When we bring ourselves into new and friendly business relations with 400,000,000 of people, 03cupying a vast territory, and with a diversified cUmate and soil, we may well hesitate about our conclusions — and this Centennial year joins us to China and Japan by ties more close and direct than it has been the fortune of any of the nations of Northern and "Western Europe to enjoy through all their previous intercourse. The influence of climate also finds a notable illustration in the character of hides and skins taken oif in the new Prairie States of our own country. All concede that the species, and even the breeds, are the same as with us in New England and the Middle States, and yet the texture of their hides and skins is much coarser ; particularly is this true of the calf and kips of those States. The reasons for this con- ceded fact are as follows : The cattle are seldom housed, even in extreme winter. The farmers have no barns, or even pro- tecting sheds, and the cold »so overcomes the cattle as to seriously affect their growth. This may be noticed in their calves. A calf dropped by a cow in the Prairie States will hardly stand on its feet until eight or ten days old, while at the East they will caper and play within twenty-four hours. The calf from a well-cared for cow, at the East, will mature and its meat may be eaten in three or four weeks, while at the West from six to eight weeks is required. This same want of strength and growth is as observable in the pelt as THE LEATHER MANUFACTURE. 193 in the meat. The difference between the " drop " or " dea- con " skins of Ohio and those of Northern New York should, according to the theory heretofore given, be in favor of those of Ohio, for there is fully five degrees of latitude against New York, but with us the cattle are carefully housed dur- ing the fall and winter months, and this care more than com- pensates for the difference in climate, and results, as all tan- ners fully understand, in giving character to the calf pelts of the respective regions. In accordance with this perhaps too hasty conclusion in regard to the effect of care and culture of the neat cattle upon their offsi3ring, the question arises whether ths conceded fineness of texture and perfect growth of the Grerman, French and Swiss calf may not in some measuie be attributed to the almost humane care which is bestowed in these countries upon their domestic animals ? And if this fineness of tex- t-ire extends to the skins of the offspring, may not the hide of the parent animal be measurably affected ? These may be mere speculations, but they are based upon considerable ob- servation, and have received the sanction of cattle breeders of much renown. The cows of Holland occupy the warmest and best portions of the family dwelling, and are cared for with as much tenderness as any of the inmates. It may be said of the domestic animals of all Central and Southern Europe that they are cherished and cared for in a much larger measure than the human family, supposed to be their lords and masters. May not this culture and care have some- thing to do with that superior growth and texture which seems to characterize their calf, goat and sheep skins ? This discussion may be too general to satisfy tanners that breeds, climate and food control the value and qualities of hides and skins, and yet they must admit that the theory here broached is in accord with common observation. 13 CHAPTEE XXII. FBENCH AND GEKMAN CALF AND KIP. WHEEE OUR IMPORTED STOCK COMES FROM CAREFUL ASSORTING OF THE RAW STOCK TO INSURE UNIFORMITY IN WEIGHT, SUBSTANCE, AND GEN- ERAL CONDITION SOAKING AND MILLING — BREAKING THE NERVE LIMING BATING AND WORKING OUT LIME COLORING AND HA>:dL1NG LAYING AWAY AFTER WORKING STUFFING DRYING SLICKER WHITENING BLACKING AFTER THE STOCK IS CUT OUT USUAL IN EUROPE VEGETABLE OILS USED INSTEAD OF FISH OILS DEFECTS IN FOREIGN CALFSKINS — STEADY IMPROVEMENT IN AMERICAN CALFSKINS. In wliat is here said of Frencli and German metliods of tanning and finishing calf and kip skins, the statements may be regarded as applying also to the production of this class of stock in Switzerland and Austria. Indeed, contrary to the general impression on this subject, these countries are about equally represented in the manufacture of this descrip- tion of light imported stock, commonly styled by consumers "French" goods. We seldom hear of "Swiss" calfskins, although Mr. Mercier, of Lausanne, Switzerland, is the largest manufacturer sending leather to this country. The common designation of " French," as applied to all imported skins, arises from the fact, probably, that American agents for the purchase of these skins reside mostly in Paris, and ship largely through French ports. This consideration is important in this connection only as showing that a charac- teristic and almost uniform system or method of manufacture THE LEATHER MANUFACTURE. 195 pt cviiils in all the countries mentioned, and tlie goods they produce may, therefore, be treated as one manufacture. There is one other preliminary consideration which should be li ne stated, viz., only the best goods of manufacturers on the European Continent aie sold to this country or to Great Britain — that is, only those parties that manufacture calf and kip as a specialty, and in large quantities, ever think of selling their products away from home. Of the ten thousand and more tanners of these countries probably not more than fifty find a market in the United States for auy considerable portion of their stock. The local or country producers of calf and kip in all these countries labor under the same dis- abilities as do the large number of small tanners in our own country. They are not able, from their limited facilities, either to obtain skilled labor or to make the same selections as do those tanners who make a specialty of this class of goods, and do the business in a large way, and hence it is that the people of Continental Europe generally wear no more artistic calf and kip than may be found in the shoes made up for the ordinary wear of a large portion of our own popu- lation. In respect to weight, substance and general condition, the skillful foreign tanners take especial pains to see that the skins of each pack shall be as nearly alike as possible. In this respect their practice does not differ from the theory of our largest and best calfskin tanners, but by reason of the large unmanufactured stocks which they usually carry they are enabled to put their theories into practice more thoroughly than it is possible for our tanners to do. Their calfskins are for the most part dried without salt and folded on the back ; the selections for weight are then made, and the skins are ]iacked in bales. This is done by the factor or dealer. "When the goods reach the tanner he still further assorts and then lOG THE LEATHEE MANUFACTURE.. packs tliem aAvay in cool lofts where tliey await liis want?. How different these circumstances from those presented to our large calfskin manufacturers, who buy all their stock in a green salted state from the 1st of May to the middle of July ! The condition of the green salted skins as handled by our tanners taxes their best energies ; to keep them from salt pricking and decaying is very difficult, and the tanner is forced to hurry them into the tanuing process with indis- criminate haste. When skins in all respects alike go into the soak, they are equally affected by the water, and are ready for the mill at the same time, thus enabling packs that are commenced to- gether to go through to the end without separation or divi- sion. This uniformity also greatly aids the general economy of the manufacturing by keeping the tanner informed of the amount of product which he is realizing from his raAv mate- rial, for each pack or series of packs will indicate to him liis loss or profit. Aside, however, from the general merit of this classification at the start, it may be asserted confidently tliat no tanner can make uniform and good stock without such selection, even with the greatest care in the after handling. The treatment necessary at this stage of the process will be greatly influenced by the condition of the stouk. If the skins are green salted, as with us, a very slight milling will suffice ; but if they are flint dry, as with some of our small tanners, then the}^ should be thoroughly softened. But any forced softening must be preceded by a certain amount of soaking, which in turn will greatly depend on the condition, whether green, green salted, dry salted or absolutely flint dry. The soaking process will, therefore, extend from a few hours to a few days, depending upon the condition of the skin and the s'ate of the weather. If the skins are flint dry, they should not be milled until afler ample soaldng, and even hand- THE LEATHER MANUFACTUnE . 197 linp; i:i the soak; but tlie first milling should be gentle, otLer- wise tlie grain of tlie skin may be cracked. This milling should be only for a few moments, and with a full mill, so that the large body of skins will present a soft, yielding mass to the action of the hammer, if the softening be accomplished with the ordinary fulling stocks. If a revolv- ing wheel is used, then the same care is necessary that the skins may not have too violent a pounding on the inside wooden projections. After the first slight milling- the pack may again be returned to the soak or thrown up in piles. The action of the water in the second soaking will be much more rapid, and great care should be taken that the grain does not " prick." After the pelt has been in this manner made as soft as water and ordinary milling will accomplish, then we notice the first peculiarity in the methods of the French and German tanners, as compared with the practice here, which consists in the thorough breaking of the nerve. The nerve to be broken is a description of interlacing fiber which holds the animal tissue. This nerve is located trans- versely on the flesh of all pelts. It may almost be said to make a part of the flesh itself, and lies immediately under that loose, fleshy tissue which curriers shave off before they reach the pelt proper, on which they form their waxed sur-- face. The office performed by this nerve or tissue is, by its contraction and expansion, to hold the pelt close around the animal. It forces the pelt to conform its shape to that of ihe animal whose body it covers. When the animal is fat r.nd well rounded out it expands, and when poor, sick, or thin, it contracts. It is this nerve which induces " bag- i''ing " in all leather, notably in sole leather, while in harness and upper leather, which is stretched by shaving and scour- ing, much of the contracting force of this nerve is destroyed. But something more and beyond the avoidance of " bagging" 198 THE LEATHER MANUFACTURE. is required in the preparation of calfskins. The nerve must be so completely severed or broken that the whole pelt wdl feel not only soft, but ad.itcdly V^<^''Pi)- This effect can only be produced at present by hand labor. No machine has yet been devised to do it, although it may be predicted that, when the great utihty of the work becomes appreciated, a labor-saving machine will come forth from the brain of some American to perform this labor. The h, de-working machine of Mr. Henry Lampert, of Eochester, N. Y., when improved, may answer the purpose, or suggest the way to some other and better machine. If the skins are dry or dry salted there is no difficulty in determining when this nerve is sufficiently severed ; but if they are g: .^en or green salted, unless more than the usual care and conscientiousness is exercised on the part of the workman, the nerve will remain unbroken, and will hold the whole fiber of the pelt firmly during the entire after tanning process, so that it becomes difficult if not impossible ever afterward to make a yielding and elastic substance from the skin thus treated. Assuming that we have succeeded in breaking this nerve, and have brought the pelt to a soft, pulpy condition, the next process will be liming and unhairing. The skin has been brought to a condition in which it will readily take the lime, and four or five days in a moderate lime water will neu- trahze the animal grease, and soften and swell the roots of the hair so that the latter will come off with the most incon- siderable labor. No more Hme need be used than sufficient to accomphsh these two objects, although the practice in this respect is not uniform ; the statement is made rather on a knowleclge of the American experience than from personal observation as to the practice of foreign tanners. When the hair is removed the skins should be thrown into THE LEATHER MANUFACTURE. 199 the mill or wheel and washed for a few moments. If in warm weather, water at a temperature of 60 degrees should be nsed, but if the weather be cold, the removal of the lime will be greatly facilitated by using water a temperature of from 80 to 100 degrees. This warm water and milling process must be conducted with judgment and care, but when so carried on it is pr rfectly safe, and considerably shortens the process of depletion, besides saving the expense of other depleting agents, usually called " bates." * The lime must be worked out before the skin goes to the handler. In the practice of some of our American tanners, the acid of the liquor is relied upon to overcome a portion of the lime which may not be readily removed, very much as is done by some of our sole leather tanners ;' but, according to the best French process, the lime must be thoroughly worked out liefore the skin goes into the handlers, and all the work- ing is done on the grain rather than on the flesh side. The result of this treatment is that the skin, when properly pre- pared for the handlers, is so depleted that the pelt of an oi-dinary eight-pound green veal skin can be drawn through a ring two inches in diameter. After all that has been said or experienced by tanners, it is probably true that much depends on the kind of liquors which are applied in the handlers. Skins depleted by bates in the ordinary way, and subjected to sweet liquors in the handlers, will, undoubtedly, give a finer flesh and a tougher fiber than when otherwise treated, but whether the skin will be as plump and as full in the offal may well be doubted. If, however, there is any lime left in the skin, sour or acid * Some of the best and largest tanners of Switzerland depend very largely on the sour acid liquors of the " larch " bark, both to form their color and at the game time deplete the skins. One of the most successful calfskin tanners oj^ SAvitzerland told the writer that he did not consider it safe to deplete with ordi-» narv bates, and then trust to sweet liquors to color and tan the fiber. 200 THE LEATHER IVLVNUFACTUEE. liquors must be so far used in the coloring and earlj tanning process as to overcome the last particle of lime, otherwise the tanner will have a coarse flesh and spongy fiber that will not " carry " stuffing in the finishing process. The methods of coloring and handhng followed by the tan- ners on the Continent of Europe, so far as they came under the observation of the wiiter, would probably fail to give sat- isfaction to American tanners. The handling there is done in vats, with old sour liquors, rex:)lenished with either "]arch" or partially spent " oak " tan bark. About one-half of a pack is put into a round or square vat, and a man is constantly employed in raising the skins to the surface by means of a pole, very much as was the practice of our tanners fifty years ago. Other tanners, more advanced and doing business in a larger way, have a revolving wheel in the top of their vat, constructed and operated very much after the style of our so-called "England" wheel. The process of merely coloring and handhng soon termin- ates, and then the skins are paired and laid away, grain to grain. The object of this grnin to grain laying away is two fold — first, to tan the skins from the flesh side ; and, second, to keep the grain smooth and tough. Both of these objects are accomplished by this process, and, next to the breaking of the nerve in the beam house, this may be considered the most important innovation upon our method. The skins ai'e paired according to size, and carefully laid pate to pate and butt and butt, a matter which is not difiicult in a pack that has already been selected with great care to secure uni- formity in weight and substance. A man will size and plr.ce these skins grain to grain almost as fast as he could handle them in any other way. When so placed and held by the hind shanks with both hands, they are passed to a man in a deep round vat, from which the liquor has been drawn. This tut: leather manufacture. 231 r.-_an first tal- tion on (M N) " being through the boilers and brick work back of oven. The furnace at Wilcox has been selected to illustrate this article in preference to a new design, because it is a furnace in actual use, which gives perfect satisfaction, and because, as it has been already built, the cost is accurately known. It will be eeen that it really consists of two complete sets of ovens and boilers, the only thing in common between them being the chimney and fire room. Each pair of ovens has its own set of boilers, its own feed water tank marked "T " and "T"in figure 1, plate III. Either pair of ovens would be nearly large enough to supply steam to run the whole tannery if the other pair were stopped, either by accident or for repairs. In case, however, only one pair of ovens were used, it would prob ibly be necessary to burn nearly all the hark leached, while, when both pairs are used, it is only necessary to burn about one-half the bark Each pair of these ovens is prob- ably capable (if forced to the utmost) of burning one and a half cords of wet spent tan per hour, which would evaporate 9,000 pounds of steam, being equivalent to about 180 horse power. In actual practice at Wilcox they burn one-half a cord of wet spent tan each, each pair of ovens per hour evap- orating 8,000 pounds of water, being equivalent to 160 horse power from both ovens. This steam runs the whole tannery, except the rolling loft. The foundations of the ovens and chimney are not shown in the plans. They should be of stone and should go down in the ground below the action of the frost. The foundation under the chimney, on account of the great weight it has to bear, should go deeper than this, or at least six feet below the original surface of the gi'ound, and should be a foot larger than the base of the chimney all around. The first 238 THE LEATHER MANUFACTURF. slep in tlio construction of this furnace would be to mark out on the ground an area two feet larger each way than the outline of the building, 'and then excavate all the earth from this space three feet deep. Next, on the bottom of this ex- cavation, mark out the position of the walls, and dig a trench two and a half feet wide and two and a half feet deep under each. Thus there" would be four trenches under the four walls of the building, and in addition, four trenches parallel to the side walls under the four dividing walls of the ovens and boilers. The foundation for the chimney will come in the center, and should be fourteen feet square and go down four feet below the bottom of the excavation, or seven feet below the original surface of the ground. The foundations under the two wings containing the feed-water tanks may be two feet wide, and sunk three feet below the original surface of the ground. The walls of the ovens are commenced on these foundations, three and a half feet thick, but with a batir of one foot in the hight from the foundation up to the level of the fire room floor. From this point they are per- pendicular, and of a uniform thickness of sixteen inches. At the fire room floor, therefore, the oven walls are two and a half feet thick. The walls of the feed- water tank rooms may be sixteen inches thick. The dividing wall between the ovens has a imiform thick- ness of one foot ten inches up to the level of the grate bars. The fire brick linings of the ovens commence at the level of the grates, and are set back two inches on each side to leave a shoulder for the grate bars to rest on. The grate bars are each three feet long. One end rests on this shoulder, and the other on a wrought iron bar (a worn out piece of railroad track answers very well), which runs the whole length of the furnace, and is embedded on the walls at each end. There are four one and one-quarter inch iron rods, each twenty THE LEATHEK MANUFACTURE. 239 feet long, with a thread and nut on eacli end, and cast iron washers, through each oven, under this bearing bar, to tie the side walls together. The whole inside of the ovens, and the tops of the bridge walls, and the inside of the walls under the boilers, are lined with fire brick. The holes for feeding t''e tan through the top of the arch into the oven are lined with fire brick which must be made of the required shape by the manufacturer. The side walls of the ovens rise verti- cally for one foot, and are then turned into a circular arch of three feet radius. The lining of this arch should be of fire brick not less than six inches thick, and there should be in addition two courses of common brick, so that the whole thickness of the arch is fourteen inches. The fire room floor may be of brick, laid on edge, and the space between the arches under the floor filled up with broken bricks and mor- tar. There are four doors through each outside wall of the ovens. These must be made with arched tops of fire brick, made the exact shape by the manufacturer. The owner of the furnace will find it to his advantage to have the brickwork around the ovens constructed with great care, as if carelessly biiilt it will crack, or even fall down, in a few years. The heat in one of these tan-burning ovens, although not so great as in ^ coal fire, is greater than in the ordinary furnace when the grate to burn the coal is under the hoiler. A plan of the grate bar to be used is shown in figure 3, plate V. These grate bars may be much lighter than when used for coal. The oven doors should each have a register in them, to be partly opened to admit air above the fire when the oven is in use. Through the courtesy of Mr. Judson Schultz, of Wilcox, Pa., I am enabled to exhibit the exact cost of this furnace in 1872. At the present time (September, 1876) the cost would probably be 25 per cent. less. 240 THE LEATHER MANUFACTURE. COST OF FURNACE AT WILCOX, 1872. BricJfwork — Chimney— 35,000 bricks, at $6 00 $210 00 Two masons, 20 days, at $5 00 per day 200 00 Three helpers, 20 days, at SI 50 90 00— $500 GO Ovens and Walls— 112,500 common brick, at $6 00 675 00 5,800 fire brick, at $60 00 348 00 One-quarter-circle bricks, for arch 100 00 Three masons, 52 days each, at $5 00 per day 780 00 Two helpers, 50 days each, at $1 50 per day 150 00 Digging foundations, hauling stone and sand 300 00 — 2,353 00 Boilers Etc. — Six boilers and standards, with two mud drums 3,575 57 Four furnace doors, four back connection doors, four doors to enter under boiler, two smoke jacket doors, one chimney door, 5,536 Tbs, at 5%c 303 48 Back stays, 8,062 fts, at 5c 403 10 2,048 grate bars, 26,175 lbs, at 4^0 1,177 88 Washers, 130 fts, at 5^/0 7 15 Dampers and smoke jacket 58 00 Tie rods under grate 100 00— 2,049 61 Eoof— 3,000 feet of lumber for rafters, at $10 00 30 00 Labor 50 00 Sheet iron 325 00— 405 00 Total cost of oven and fixtures $8,883 18 Taking the total cost at $7,000, it will appear tliat the original investment in the furnaces will be at the rate of 7 cents for each hide tanned annually, and that at 15 per cent, (allowing 7 per cent, for interest on capital, 3 per cent, foi annual repairs, and 5 per cent, for a sinking fund), the annual cost wiU be $7,000X-15^$1,050, or about one cent for each hide fanned. If it were required to build a cheaper furnace than that at Wilcox, the brick walls above the ovens and boilers and the iron roof may be omitted, and wooden walls and a wooden roof used in their stead. If tubular boilers in place of fine boilers are used, the cost of the boilers will be less, and the brickwork setting will cost less. If the feed water is free from sediment and scale, tubular boilers will be just as economical as flue boilers, but will not THE LEATHER MANUFACTURE. 241 Inst so long, and Avi]l need more unremitting attention on tlie part of the engineer to keep the water at the correct level. On the whole, they are not to be recommended. Plates IV, V, VI, represent an oven for burning wet spent tan when the tan is shoveled in to the oven through an ordinary furnace door like coal or wood. P'ate V is a section through the center of oven and middle boiler, showing the oven grate and ash pit, the boiler, steam and mud drum, and the front and back connections. Plate VI, figure 1, represents, on the left hand portion, an elevation of the front of the oven, showing one furnace and one ash pit door and half of the middle furnace door, and on the right hand portion a section through the oven showing the top and sides of the oven, the thickness of the brickwork and the grale bars. Figure 2 is a section through the boiler, back of the oven, showing the three boilers and flues, the steam and mud drum and the thickness of the brickwork. The unshaded bricks represent the fire brick in all three plates. Furnaces fed from the front like this are generally considered cheaper to build than those fed from the top, but this is because they are generally made smaller in proportion to the size of the tannery thnn those fed from the top, and are therefore ordinarily much less efficient. If both furnaces are built of the size required to give the best results,, the furnace fed from the front will require to be the largest and will cost the most. The construction will be readily understood from the plans. Tlie plan of the grate shown in figure 3, plate V, has been found in practice to be strong enough. There are two lengths ©f these grate bars, each 2 feet 8| inches long. The back length is level, but the front length should be raised from six to eight inches in front to facilitate feeding the tan toward the back. The ends of the grate bars must be carried by 16 242 THE LEATHER MANUFACTURE. wrought iron bars, reaching across the oven and built into the brick work at each side. An old piece of railroad iron will answer, or a piece of wrought iron four inches deep and one inch thick. The furnace and ash pit doors may be made of a piece of boiler iron a quarter of an inch thick, with the hinges and latch riveted on. The lugs to carry the hinges, and the latch, may be built into the brick wall, thus dispensing with the cast iron door frames. The furnace door should be double, the inner lining of boiler plate being punched full of quarter inch holes two inches apart. Both the ash pit and the furnace doors should have openings through them with registers. The three furnace doors should be each 20 inches wide and 18 inches high on the outside, spreading out wider on the inside, as shown in the plan, plate lY. The ash pit doors should be 16 inches wide by 24 inches high in the clear. The fire room floor should be 24 inches below the si 1 of the fur- nace door, or 18 inches above the bottom of the ash pit, as the fireman can shovel in the tan easier than if the floor is as low as the bottom of the ash pit. The brick work around the oven must be tied up with buck stays and iron rods, as shown in the plans, for as the arch over the top of the oven has a wide spread, it exerts a gi'eat pressure on the side walls. Also the fire bricks in the arch must be laid with care with narrow joints, or they will fall out after the furnace has been a little while in use. The smoke connection in this furnace is shown in plate as built of brick running across the boilers over the top of the oven. This connection must lead to the chimney built on either side. The chimney should be eighty feet high and twenty-four inches in diameter. The back ends of the boiler are carried by the mud drums, and the front ends by a piece of railroad iron built into the brick work over the oven. 248 THE LEATHEE MANUFACTURF. Until within a few years it has been considered indispen- sable that the " sweat pits " of the tanner should be under ground, but now they are placed on the top of the ground, with earth or some other non-conductor sun-ounding and covering them. It is far more desirable that the bottom of the pit should be on a level with the beam house floor, or so nearly so that a wheelbarrow can be run from one to the other, than that there should be an earth or rock excava- tion surrounding the pit as was formerly thought necessary. The present plan enables the pits to be properly lighted both from the ends and tops. These pits should be large enough to properly hang one pack each, whatever may be the size of that pack — usually from 100 to 200 sides. The ceiling should be at least eight, and if ten feet high all the better. There should be a space of at least two feet from the lower portion of the sides, while hanging, to the floor, for the purpose of allowing the free in- troduction of steam under the pack, if the pit is too cold, and of cold spring or well water if too warm. The temperature should be about 60 to 70 degrees. The air should never be dry, but kept moist by the introduction of steam or cold water. Usually the atmosphere will regulate itself. The wet pack, hung in an atmosphere of 65 degrees, will impart its moisture, which will condense so that drops of cold water will stand on the surface and show on the hair of the hide, precisely as from the ox when profusely sweating from over exertion. The mode of hanging will vary with the judgment of the tanner. Some hang over sticks, others hang from tenter hooks. But whatever way hung, the sides or hides should be so placed that the attendant can readily reach each side, so that as soon as the hair of even one side or hide begins to " come " it should be dropped to the bottom, and when that of a majority of the pack " starts " they should be re- INTEEIOPt VIEW OF SWEAT PIT. 250 THE LEATHER MANUFACTURE. moved ; but if proper care lias been taken to have the whole pack in the same condition and of the same weight and sub- stance the whole pack will come out about the same time. From five to seven days' time will sweat an ordinary dry hide in one of these pits. The ventilation of these pits should always be under the control of the attendant. One of the views presented gives a lengthwise view of sev- eral pits, and the other that of a single pit as seen from the door. THE "SHOVEE" hide MILL, The three sectional plates herewith given present a fairly intelligent working plan of the ordinary " fulling stocks " for softening hides. This form of mill has so completely taken the place of the old-fashioned " falling stocks " as to render it unnecessary to present a drawing of that discarded machine. The capacity or xjower of this mill to soften dry hides is almost without limit. One mill of the size here contemplated, run at the rate of sixty to eighty revolutions per minute, will soften 1,000 hides of ordinary weight in one w^eek, running for twelve hours per day. It is within the writer's knowledge that a mill of this description has been made to soften 100,- 000 dry hides in one year, being run night and day. In the drawing this mill is geared from above, but the power is otten attached from beneath, and where this can be done it has the advantage of greatly facilitating the workmen in feeding the mill and handling the hides. "With the latter attachment the arms of the mill are es tended down through the hammers, and the bottom of the mill and driving shafts are attached below, just as they are represented in the draw- ing to be attached above. These mills, as formerly made, of hard wood plank, would wear out with one year's constant service; but lined and faced with cast and wrought iron, as THE HIDE MILL. 252 THE LEATHER MANUFACTURE. is now customary, tliey will last for many years. Tlie form of the mills varies slightly with the different makers, and the size as well. Tanners who are about to adopt this method of softening hides will do well to examine with care the most approved angles and motion of mills now in use in our best yards. The double action of these mills is as well adapted for skins and pelts of all kinds as for dry hides. There can be no doubt that from this form of mill the idea of the mod- ern "washing machine" was taken, and in turn the tanner is indebted to the clothiers, and chamois and oil dressing leather manufacturers for the ideas contained in this most efficient hide softener, for with some variations of form it is a reproduction of the fulling stocks of the clothier a century ago. It was introduced among American tanners about the year 1830, at Salem, Mass., and did not find general accept- ance among hemlock tanners in the State of New York until 1850. THE HAND REEL. On the opposite page will be found a representation of a hand reel, which is commended in Chapter YIL, on " hand- hng." The facility with which packs may be thus trans- ferred from one vat to another commends this skeleton reel to all tanners. It is safe to estimate the performance of this machine with two men as«equal to that of six men by the old hand process. Besides, it does not require either maa to stoop in his work, and the labor is therefore much easier. The stand and skeleton drum should be made of as light material as possible, so that its transfer from one vat to another may be effected by the two men with ease. As there need be but one of these reels in any ordinary sized tannery, the tanner can well afford to have the frame, drum and bear- ings made of substantial- but light materials, well adjusted in THE LEATHER MANUFACTURE. 254 THE LEATHER MAmiFACTURE. all parts, even Avitli brass bearings. The whole need not cost over ten dollars. If still more ecobomy of labor is required, these reels may be driven by power from shafting nnd pullies permanently running overhead. But it will be found that two men can shift ten thousand sides in ten hours without the use of power. The sides may be tied together with strings or connected with a tie-loop ; strings are preferable, and are quite inex- pensive. THE EOCKER HANDLER. The accompanying drawing will serve to give a correct idea of the rocker handler, which is now held in such high esteem. The gentle and intermittent motion required should be given from shafting from above. This shafting should run over the center aisle, and have projecting arms, from which there should extend a connection to each of the frames of the rockers. This connection may be by a pole or strip of plank two inches square, made of any tough timber, and so ad- justed as to be readily disconnected. The vibration of the rocker on which the leather is hung should not be over four or six inches, thus causing as little agitation of the liquor as is consistent with a gentle movement of the fiber of the green stock. (See Chapters YII. and YIII.) 256 THE LEATHEli MANUFACTURE. I THE AMEEICAN LEATHER ROLLER. The skelefon drawing on the opposite page represents the universal American roller. The only patent now existing on this roller, as here presented, is on the leverage under the table. The whole cost of this leverage is $30, on which there may be a profit of $10 for the patentee. The roller bed is made of wood or metal ; the one in the drawing is made of copper. It is cast hollow, and is valued at about $40. The whole machine will cost about $200, including tlie woodwork, table, etc. Such a machine will roll about 100 sides each day of ten hours. The amount of pressure which can be brought to bear on the side has absolutely no limit. It is claimed that a side of sole leather can be cut in two if the whole power of the lover is evoked. 17 258 THE LEATHER MANUFACTURE. T>he representation on the opposite page shows the new form of dryer, now so generally in use. The building may be of any hight or shape ; the engraving is of a structure of four stories, besides the basement floor. This lower story should be reserved for steam pipes, or other means of hea^- incr All the floors above are latticed, and when not obstructed by dampers, allow the free passage of aur to the top opening. The draft may be regulated by " stops " or "dampers," either at the openings on the lower floor or at the top openings, or both, the object being to absolufely con- trol the currents of air, so Hatonly so vnich, mid at such periods as the attendant may desire, icill air he alloicfd to pass. If glass wmdows are used, as shown in the drawing, they are only to give light to enable the work to be done, but never to be opened for the purpose of admitting air or light to reach the leather, and when the work is done they are to be covered with a window shade, so that the leather may be excluded from the light during the Avhole drymg process. This form of dryer is built on the plan of a chimney, and the laws of its action are precisely like those of that essential ventilator to our dwellings ; if currents are permitted to enter otherwise than at the bottom, counter currents will be formed in the dryer, and it will not " draw," but if the air is confined, then the difi'erence between the temperature of the air at the ground and that at the elevation at the outlet will cause the current to rise, and rapidly just in proportion to its hight. Hence, to get a satisfactory self-acting turret, the building should be as high as possible. For more specific suggestions regardii^g the economic use and management of these dryers see Chap- ter xn. THE LEATHER MANUFACTUEE. 259 THE TURRET DRYER. 260 THE LEATIIEll MANUl- ACyrUilE. THE ALLEN & WARREN SPRINKLER LEACH. This is a " percol iting " process of leaching bark in contra- fdstinction from the " press " system. Both methods are in vcr}' general use in this country. The Allen & Warren method is known as the " sprinkling" process, and is shown in the drawings. Many tanners, however, accomplish imper- fectly a similar result by flooding their leaches with a limited quantity of liquor, allowing it to percolate through, and then flooding again and again, each time with about one-third of a vat of liquor. But if percolation is to be practiced at all, there can be no doubt that the Allen & Warren method is to be preferred. This sprinkling process has been so much abused by tan- ners, and so much damage has been done thereby, both to the color and general quality of the leather, that a strong preju- dice exists in the minds of many against this method of leach- ing ; but it is believed that if the new bark is leached with cold or only warm water or liquor, then a concentrated and pure liquor can be obtained, while if the head liquor is heated up to, or near, the boiling point, and is then sprinkled on the new bark, an undue amount of coloring matter will be carried down and find its place on the leather, making both a dark color and a harsh texture and fiber. The practical working of these leaches proves that " strength" can be more concen- trated with them than by any other means ; hence, for extract manufacturing, they are serviceable, and we should judge that fully one-half of the hemlock tanners of the country are using them, without appreciating their good qualities or avoiding their bad ones. Tlie heater box, by which the exhaust steam from an en- gine will heat a constant stream of water or liquor without in the least reacting upon or retarding the power of the en- gine, may be seen in the two lower engravings. The sec- THE LEATHER MANUFACTUEE. 2G1 262 THE LEATHEll MANUFACTUllE. tional figure represents two slielves, c and d. These are set on an incline, so that the water or Hquor, which enters at a, fills the compartment h, until it overflows on the inclined shelf c, passes down on the inchned shelf d, and so finally out of the discharge opening e. The steam from the engine takes the opposite course, entering at /, passing through the liquor or water until it finds its way out at g. The steam thus passing will fully condense, and only moderately-heated air will pass off. The other drawmg represents the enclosed box, with these shelves inside. By this simple and inexpensive construction of plank a most effective heater is made, and by its use a constant stream of hot water or liquor can be run through on to the leaches. If the most perfect heater possible is desired tlu n small holes maj be made in the shelves, in which case they should be made of cojtper plates—then the perforations can be small and effective ; they will rain down small drops, condensing the steam most perfectly. This is one of the best and most effective improvements ever made in the heating of hquors. There is no patent claim on this improvement. THE BAEK CUTTING MACHINE. The accompanying cut is designed t » show the new mn- cliine for sawing tanners' bark. There can be no doubt that this machine does prepare bark for leaching better than any known bark mill of ordinary construction. It will saw damp or even wet bark with the same facihty as if it were dry. If the bark is in large pieces it can be fed into the mill with facihty, but if small then it will require a hopper or some other contrivance not yet perfected, certainly not practically introduced, to facihtate the feeding. It is claimed that a sin<^le mill will cut one cord and a half per hour. To do 264 THE LEATHER MANUFACTURE. this we should judge that the circumstances must be very favorable. The high cost of this mill, $300, will probably restrict its use ; it is, however, far better for tanners to pay even this price, unless it is possible to secure an equally good result by some more economical method. That other method is, in our judgment, by the use of a wire screen, as expressed else- where. There is no excuse for attempting to leach coarse and unevenly ground bark. THE KEYSTONE BABK MILL. The skeleton form of bark mill presented on the opposite page is probably the most skillfully manufactured machine of the kind known to the trade. We have taken special pains to describe its pecuHar construction and its performance in chapter V, to which the reader is referred. Great pains are taken to make this mill run true ; the ability to replace the surface segments, by either steel or cast iron surfaces, renders it one of the most serviceable, and, when we consider the safety coupling with which it is connected with the driv- ing shaft, it is one of the most duraUe mills known. If tan- ners either cannot or will not adopt the wire screen, then we say this mill will grind more uniformly than any mill offer- ing to the public, but it will not grind wet bark any more than will other cast iron mills. THE HOWARD SCRUBBER. As the drawing indicates, this scrubber consists of two skeleton drums, with projecting arms, into which are fastened birch brooms, closely held. The drums are rolled together by the cog gearing as seen on the side. When ready for work the box or covering marked A is dropped down, and through the slit or opening, G, the sides are fed. The feeding is per- THE LEATHER MANUFACTURE. ALLENTOWN BARK MILL. HOWARD LEATHER WASHER. 2G6 THE LEATHER MANUFACTURF. formed by allowing one end of the side to pass down between the revolving brushes ; if the side is firmly held and allowed only to pass down slowly the surfaces will be thoroughly scrubbed, and well done just in proportion to the time al- lowed. To do the work well each side must be passed through twice, once from the head and once from the butt. One of these machines with two men to attend it will scrub about four huLdred sides per day. It is simply justice to say that the " drum scrubber," elsewhere described, is taking the place of this Howard machine in some of our large hemlock tanneries, and tannevs will do well to examine the merits ol both before adopting either. THE SALEM WET TAN PRESS. This lever roller serves a most useful purpose for squeezii^ out the remaining ooze from spent bark, previous to burnijj it. Just to the extent that water or spent ooze is taken from the bark is the bark rendered serviceable to burn. It is now demonstrated that Thompson's patent for burning water, (which is equivalent to saying that wet tan will give more heat than dry tan), is a fallacy. But whether the power lost by sqtieezing out the water is not the equivalent of power lost in drying out the water in the oven is a question never yet determined by actual experiment. This Salem machine is fully as efficient as the French and English machines for the same purpose, and seems more sim- ple in construction. It is regarded as serviceable where the tanner requires more power than he can gain by the use of wet spent tan burned in an ordinary oven ; but aU sole lea- ther tanners have an excess of tan, and, therefore, can never require this wet tan squeezer. or less destroy the grease and impart a harsh feeling to the which Mr. Korn closed his observations : " Writers of books THE LEATHER MANUEACTUEE. 267 THE SALEM TAN PEESS. 268 THE LEATHER MANUFACTURE. THE LOCKWOOD AUTOMATIC LEATHER SCOURER AND HIDE WORKER. On the opposite page is an illustration of this new inven- tion, patented July 26th, 1876. The machine is novel in construction, simple ia its movements, and ingenious to the extent of almost running itself, as the weight of a man's finger can guide the scourer over the surface of any kind of thick or thin leather. The patentee claims it to be a machine complete in itself, independent of building or framew^ork ; it can be set up without bolting or bracing, is durable, being made of metal of the utmost strength, and with air cushions which relieve the working parts of thrusts and strains. The machine can be set at any angle with the line of shafting, and belted on either end from above or below. Only from one to three horse power is required to run it, according to the thickness of leather being dressed. It occujjies but little more space than an ordinary currier's table. It seems almost automatic in its movements, and is capable of the Avidest range of work, from the lightest to the heaviest ; will scour, set out or glass, and can be made to take a slow or quick stroke, a long or a short one, making the most perfect stroke attainable with the smallest Joss of motion, which is effected by the epi-cycle and cam combined. 270 THE LEATHEE MANTJFACTUEE. THE EITZHENRY SCOUPJNG MACHINE. This machine has been so universally adopted, not only in this country but throughout Europe, that it is perhaps doubtful whether it should not be excluded as one of the old inventions, too well known to be entitled to a place in this volume, which claims only to present novelties, or such ma- chines as are confined in their use to localities, and are com- paratively new. But since within a few years we have an- other, and within a few months still one more, competitor for the honors of recognition, all three nre given in contrast. 272 THE L;::ATiIErt MANUFACTUKE. THE BUEDON SCOURER. This practical and very sei viceable machine is mostly use- ful in scouring out Uoom, while it at the same time softens and cleanses the grain. It is useful for harness leather and fair leather curriers, but has not so far proved a success in scouring sole and belt leathers, which require more vigorous treatment. For calf, sheep and goat it should answer a most valuable purpose, and for grain leather it must prove a very efficient machine. The high cost of the machine has no doubt prevented its adoption more generally by the trade. Had the improve- ment fallen into other hand-^ there can be no doubt that it would have come into general use before now. THE LEATHER MANUFACTUBE. 273 THE BURDON LEATHER SCOURER. 18 274 THE LliATHER MANUFACTUr.E. THE STUFFING AYHEEL. The accompanying drawing presents one of the commonest forms of the stuffing wheel, now in yery general use in this coimtry. Through the opening door may be seen wooden pins on which the leather falls in the revohitions of the wheel, and they also serve the purpose of carrying upward the sides or skins, and generally agitating the fiber. This Avheel may be driven by a belt, as sho^vn in the drawing, or by cast iron gear. The general methods of using this wheel have already been discussed in the preceding chapters. It was first prac- tically introduced by Mr. Charles Korn, as early as 1856 to 1860. It had its origin in Germany, but there a barrel or hogshead served the purpose, while here special wheels oi permanent construction were first introduced into the curry- ing shop of Mr. M. M. Schultz, in the year 1860, at Sparrow- bush, N. Y., under the direction of the original introducer. This wheel lias revolutionized the character of the upper leather of the country, which is now made soft and yielding, whereas before it was hard, the oil and tallow being now fulled into the center of the fiber, while under the old method, which applied the stuffing on the flesh side, it only penetrated a little beyond the surface, leaving the main body of the leather dry and unaffected. Leather prepared for this wheel should be in the same condition as to dryness as if stuffed on the surface in the ordinary way— neither too wet nor too dry. 276 THE LEATHEE MANUFACTURE. CHARLES KOKN's WHITENING MACHINE. The accompanying illustration shows Mr. Kom's wliitener, with the inventor operating it. The action of the machine is precisely that of a currier's knife in the hands of the work- man byUie ordinary beam process. The knives are fastened to an endless leather belt, and set diagonally, so that when the cut is made on the beam, as it passes down in front of the operator, there is a sliding and diagonal cut. The knives (for there may be as many as you please, certainly three or four) are cleared on their edge by one moving automatic finger, and by an automatic hand the edge is sharpened. This lat- ter performance is the most complete success, performed by the most ingenious piece of mechanism, the writer has ever seen. Ihe inventor claims that he can, with this machine, do the work of four men, and do it better than by hand work. THE LEATHER MANUFACTUKE. 277 278 THE LEATIIEli ALVN UF ACTUUE. THE "LT]S"ON LEATHER WHITENING, BUFFING AND SKIVING MA- CHINE." Herewith is presented a representation of a recently in- vented machine for whitening, buffing and skiving leather. It m simple in construction, easily kept in order, requires from four to five horse power to run it, according to the thickness of the leather, and requires only an ordinary oper- ator to perform as much work in one day by the use of the machine as is usually done by four whiteners. The quality of work is uniform and equal to that of the best skilled hand labor. The knives or blades make clean cuts, leaving no naj), and the leather, when finished, is smooth in the flanks, bellies and necks. The cylinder contains thirty -two knives or blades, inserted spirally, and a sharpener is attached, which travels forward and backward across the edges of the blades. The cylinder revolves 2,780 times per minute, and the pendulum- swings to and from the operator at a speed of 90 per minute. THE LliATHEE MA.NUFA0TU11E. 279 280 THE LEATHER MANUFACTURE. fisk's whitening and buffing machine. The inventor claims that this machine can and will do its Avork much more economically and even better than can be done by hand labor. Among its claimed advantages are the following: "It is small and compact," "runs with small amount of power," and " the table has a convex bed, and thus bends the surface of the leather from rather than tow- ard the cutter" — "consequently," says the inventor, "the square edges of the blades take hold of the leather with very little pressure, and make a light, clean cut." Some certifi- cates of those who have used the machine assert that wax leather, measuring from nineteen to twenty square feet per side, can be whitened by it in from one and a quarter to one and a half minutes, thus making about forty sides per hour. This, no doubt, is an extreme performance. The general resemblance of this machine to " the union leather whitening machine," presented on another page, will strike all who compare their general structure. The dif- ference consists in the working of the table, or the feeding of the knives. The knives themselves, and the form of sharpen- ing them, may be considered identical. There can be no doubt that this machine does good work, and far more eco- nomically than it can be done by hand labor, so that it will probably share the patronage of all tanners and curriers who profess to study the economies of their trade. 282 THE LEATHER aiANUFACTURE. "the union leather splitter," sliown on the opposite page, is too valuable to omit from any classification of American leather dressing machinery. It was the pioneer of all the improvements made. While we be- lieve there are yet patents maintained on some unimportant parts of the machine, as a whole all patents have long since expired. This machine has revolutionized the currying and finishing of leather in America, and is destined to do so in every other country. No currier can afford to carry on his business without a splitting machine of some kind, and this union machine is both the cheapest and simplest in construction. the lamper t hide worker. This eccentric machine is well designed for unhairing hides or stins. The drum "A" revolves on the axis " B " at the center, rendering it unnecessary to move the hide side- ways, but by a slight effort of the hand the drum is rolled from right to left, or left to right. The hide is drawn towanl the workman as the parts become finished, whether the machine is used as a scourer or unhairer, for it is capable of doing any work Avliich can be done with the worker. TJif stone or slicker is held by a steel spring, which in turn is propelled by the arm attached to the balance wheel. The machine should be seen in operation to be fully appreciated. Eccentric motions are now used very extensively in several departments for the finishing of leather. Grain leather of all kinds is diced, and morocco and sheepskins are glazed and polished, as well as diced, by machines which use eccen- tric motion, with modifications of form and action. 284 THE LEATHER MANT7PACTURE. OUTLINE OP HIDE WITH TEIM USUALLY MADE. The cutting of the hide in forms has become so common, from the demands of the belt, harness and shoemakers, that we haye availed of the accompanying cut to locate each part by a designated term. This nomenclature conforms in part, if not altogether, to the English classification. " A A'' are the bellies; " B B'' are the bends; "0" and "i)" are shoulders. Sometimes the shoulders are cut so as to in- clude the neck, and in that case both C" and " I) " are cut in one piece, but it is more common to cut " G " as the shoul- der. This trim will be varied by the fact as to whether the hide is a "cut" or "stuck" throat. The term "offal" ap- plies to all the parts outside of the bends marked " B B" but the pieces are separately and specifically named as above. OUTLINE AND TEIM OF HIDE. 286 THE LEATHER MANUFACTURE. tanners' and curriers' TOOLS. On the following page is a representation of a case show- ing the principal kinds of tanners' and curriers' tools in use. The center piece is a moon knife, and around this the others are arranged, in most attractive form. The two long, thin, straight knives, extending from the center toward the right and left hand upper corners, are the recently introduced Ger- man fleshers, which have of late attracted so much attention. THE LEATHER MANUFACTURE. 287 0 Plate I. Plate III. Plate IV. Plate Y Plate VI. DESIGN FOR FURNACE for burning "WEST-SPENT-TAN" ELEVATION t, SECTION THffOUSH OVEN. SECTION THKOUaH BOILEK. ADHPTEO ,oj3ui?/y(-^ co/ra to ^u^rr,,^ /600 foo^Di o^STEf^fV}) O/i \i " . -. ^600 - . , J PEK HOUK, /j^i-z/fif Tut- S'x^ /feo&/y)ms ^ Sole LsMT^im T/i/yA'£/sjr Tmiyiv/iy^ -20,000 S/D£& Ivvfe/v TH£ m/icmrvc/^y /fums JZ howh a n^y oa ren nauBie Tu/tr c/>r.ac'rj/ ( ^O.aoc J}l/Y>EfrS/o/YS C/fOSS- SECT/C V ot /^lass „ „ . ■7>0 Mo C^//Y>/Y£y ME/Q./JT OF CN'JYi^sy ho Ffi^r INDEX. A Acid, use of in handling 76 in old liquors • »^ Agitation of the fiber of hides and skins promotes rapid tanning. 183 Alkali for removing white spots 90 Ammonia in old limes • — 32 Army ofQcers, prejudice against hem- lock leather l"' B "Baggy" leather made by vacuum tanning Bark dust 51 to suppress 1^^ Bark elevators choking 139 Bark, extractive and coloring matter with tannin in 55 Bark grinding • it should be ground fine and even 47 grinding damp or wet bark 50 screening ground bark 50 E roper degree of fineness 51 emlock 156 Bark rossing 14=1 oak.... :. 159 Bark mills— the "double grinder", . 48 the AUentown mill 49, 2G5 the saw cutting mill 51, 262 crushing machine 52 capacity of different mills 53 speed to run mills 53 Bating with warm water and hen manure 34 after liming 81 Beam work 38 Blacking, flesh 221 "Black rot " in sole leather 89 Bleaching leather 100 Birch bark tanning 169 Boot and shoe industry of the IJnitcd States according to the census of 1870 244 Box vats 122 "Buifalo"vats 121 Buffing and whitening machines 41, 276, 278, 280 Buff leather 210 Burning wet spent tan, the first suc- cess in 147 Burning wet tan 47, 224 302 INDEX. Calfskins, French and German 194 the best goods made sent to Great Britain and the U. S 195 care in assorting the green stock. 195 soaking and milling 196 breaking the nerve 197 liming and unhairing 198 bating 199 coloring and handhng 200 laying away, grain to grain 200 excluding the grain from the air. 201 flesh shaving 202 scouring 203 stuffing 204 slicker whitening 205 boarding 205 kept in russet state 206 palm oil used in currying 207 Census of 1870, boot and shoe indus- try of the United States 244 leather industry of the United States in 1870 245 Chimney, dimensions of for wet tan ovens 229 Clay for a tannery foundation 119 Clewer, James', method of leaching. . 57 Climate and food, effect of on hides. . 189 Color, a natural hemlock desirable. . . 105 Color of hemlock leather improved by sumac '.101 Coloring and resinous matter in bark 56 Coloring of leather to be done in the handlers 108 Concentrated liquors obtained by the sprinkler leach 66 Conductors of liquor decay rapidly when above groiind "^^124 Cost of boiler for 20.G00-sido tan- nery '. 231 Cost of furnace at Wilcox, Pa 240 Cost of tanning, the 169, 243 " Cropping " leather 41 " Cuir " color 106 Currying and finishing 218 Cutch 163 D Dampening before rolling 97 Degras in making stuffing 221 Divi divi 165 Domestic hides of the Eastern, Middle and Western States 192 Draining after scrubbing 96 Drum wheel handler 70 Dry hides, table showing cost of tan- ning 243 Drying in the turret dryer 97 saving in time and labor and im- proved color made Ill size of building necessary 113 how steam should be admitted. .113 openings for light and air 113 elevator for raising the leather. .115 influence of light and heat 115 conveying leather from the yard to the drying lofts 136 E East India kips 191 Elevator for raising leather to the drying loft , 115 " England " wheel, the 73 Experiment mth water and tan liquor 63 in tanning Now York City hides.. 85 in tanning by hydrostatic pres- sure 177 Ferguson, Thomas T., experiment at Sparrowbush, N. Y., on vacuum tanning 179 Fertilizing liquids 153 Flesh blacking 221 Fleshing, cost of thorough work 38 lime slaughter stock 39 before hming 40 sweat stock 40 the German flesh er 41 Fisk's whitener and buffing machine . 280 Furnaces, directions for constructing for burning wet tan 224 G Gambier, or terra japonica 162 its use as a substitute for bark. . .164 Gallic acid, sole leather raised by ... 80 German flesher, the 41 German sole leather FO Glue stock, saving and caring for the. 149 Grain and buff leather 210 difference between that made fi'om tanned leather and that made from green hide 211 stamping 212 strength of 212 suggestions for manufacture of. . 213 Grain, nature of the 103 great care necessary to make it perfect 104 English custom of striking out the 108 Grate surface necessary in wet tan ovens 227 Grease on hides to be removed bv an alkali .".30, 91 how to purify and cleanse 219 Green hides, table showing cost of tanning 243 Hair, cattle and calves', saving the . . 150 cleansing and preparing for mar- ket 1,51 Handling 68 the hand reel 69, 252 the rocker handler 69, 2.54 the drum wheel handler 70 a method of raising packs 71 tub wheel handler 72 the " England " wheel 73 mechanical power 74 INDEX. B03 Handling— The " Cox" rollers.. ..... 74 on frames 75 use of acid in 76 for upper and harness leather. . . 83 Hand reel, the 69 Hanging hides in sweats 27 Heating liquors, pan for 260 Heating siirface necessary in wet tan ovens 228 Hemlock bark, a fair colored leather from 56,101 white and red 156 weight of a cord of different kinds of 156 growth of in different sections of country 158 Hemlock leather made to imitate oak leather 107 Hides, selection and classification 17 assorting at each stage of the tan- ning process 17 softening in soak and mill 18 breaking the nerve 19 kinds to be worked at the same time 21 sweating 23 hanging in sweat pits 27 liming 31 bating 33 trimming before tanning 43 skmning the cheeks and throats. 44 handling and plumping 76 laying away 84 experiment with N. Y. City 85 cells of filled mth water and not air 178 species and growth of 188 healthy and well grown 188 differences in at various seasons. 189 climate and food, effect of on 189 Hide mill, the • 250 Hide worker, Henry Lampert's 282 Hook marks 91 Howard leather washer, the 95, 264 How much leather will a cord of bark make 160 Hydrostatic pressure, experiment in tanning by 177 I Improved breeds of cattle make hides thin and spready .190 Instantaneous combination of tannin with gelatine 92 Insurance, old and new rates for tan- neries 138 Knoederer's vacuum tanning process.lSl Korn, Charles', whitener 276 Laying away, time required for sole leather 84 gives better color than handling. 85 Laying away as practised in Europe.. 86 " in Great Britain 87 weight of liquors on last layer ... 88 grain or tlesli up 91 Leaches, round or square 126 construction of 123 capacity of to be proportioned to tannery 122 brick and cement for in England. 133 Leaching 55 proper degree of heat to be used. 57 the double leach 58 the press leach 58 how it is worked 59 loam packing for 60, 119 construction of 61 operation of. 62 number of times bark is washed with 64 the Allen & Warren leach. . . .65, 260 concentrated liquors obtained by. 66 the McKenzie leach 66 revolving leach 67 Leather interest of the United States according to the census report of 1870 245 Leather should be dry when stuffed. .222 Leather splitter, the Union 282 Liming after sweating 28 when vitriol is used 29 to unhair 31 kind of lime to use 31 preparation of the limes 31 old limes 32 time required for 32 Prof. Lufldn's process 34 the " Biiffalo " method 35 handling in limes 36 Liquors, feeding hides with strong.. 82 Loam foundation desirable for tan- neries 119 Loam packing for leaches 60 Location of tanneries 118 placing the buildings to reduce fire risks 137 Loss of tannin in making leather 173 M Milling after sweating 28 Morocco vs. "pebble grain" leather.. 212 Myrabolams 166 N Nerve, breaking of the, in hides and skins 19, 40, 197 0 Oak bark 159 the rock oak, white oak, and red oak 160 growth of oak trees 161 Oiling before drying 97 Old liquors, acid in 83 One story buildings best for tan- neries 134 304 INDEX. I'alra oil vised by European curriers . . 207 Patents for tanning inventions 17G Paste 221 Press leach, the 58 " Puddling in" the vats 123 Q Quick tanning process 176 R Reel for handling leather 69, 252 Refuse of tanneries — Utilization of. .146 Rocker handler, the 69, 255 Rollers for handlers 74 Rolling, proper condition of the lea- ther for 98 effect of the first 99 a second rolling necessary 99 the American leather roller 256 Rossing bark 141 difficulty of separating the ross. .142 will it pay to ross bark for ex- port? 144 "Rouncfing" 43 Russia Leather, original color of. 106 S Safety coupling for a bark mill 49 Scouring — the Lockwood scourer. . . .268 the Fitzhenry scourer 270 the Burdon scourer 272 Screen for ground bark 50 Setting the vats and leaches 120 Sheepskins, effect of vitriol on 79 Skins — Breaking of the nerve in French and German calfskins. 20 Selection before tanning 20 Liming 34 Fine texture of French, German and Swiss calfskins 193 Size paste 221 Soap blacking .221 Soda ash, with lime, for unhairing. . . 35 Soda ash or sal soda for removing white spots 91 Softening hides 18 Soil and climate, effect of on bark . . . 156 Sole leather, German 80 Splitting machine, the 210 Sprinkler leach, the 65 Steam power to be conveyed by steam in pipes rather than by shaft- ing 137 Streams, "manufacturing" and "cu- linary" 118 Strength of liquors for handling 83 for laying away 84 for last. layer 88 Stiiffing wheel, the 27 Sugar of lead and suliDhuric acid for bleaching leather 100 Sulphur, with lime and soda ash, for unhairing 35 Sumac baths for making a fair color . 101 Sweating, in Europe 23 by steam 24 construction of cold sweat pits ... 24 to control the temperature of the pits 25 grease and salt on hides, stop- ping the action 'of the sweat- ing process 2!) improved sweat pits 248 "Sweet fern" 166 T Tan burning 47, 224 the first practical success in 147 Tanneries, construction of. Leaches 126 Framework and location of build- ings 134 The turret dryer Ill Plans, foundations, etc. 117 Tannin, difficulty of separating from extractive matter 55 instantaneous combination of with gelatine 92 Tanning materials 155 Tanning, the cost of 16;} in Europe 174 Tan press, tlie Salem 266 Tawnig hides and skins 186 Temperature of sweat pits 26 of water in wheeling limed hides. 33 of limes 35 of water for leaching with the press leach 57 of the stuffing wheel 219 Time of tanning by Knoederer's vac- uum process 183 Tools for tanners and curriers 286 Transferring packs, a method of 71 " Trim" of leather adopted by Eng- lish tanners 42 Trimming of hides 43, 28i Tub wheel handler, the 72 Turret dryer, the 110, 25;-i U Union whitener and buffing machine, the 278 Union leather splitter, the 282 Upper leather tanned by a cord of bark 170 V Vacuum tanning 177 leather made " baggy " by 182 Valonia 105 Vats to rest on the log conductors. . . 121 "Buffalo," 121 box 122 Vegetable oils for currying 207 Vitriol, the use of lime on hides raised by 28 its use in Great Britain 29 its employment in handling 76 305 INDEX. Vitriol — Difficulty in determining how much to use 78 should not be used on sweat stoclv 79 W J. Warm water to be used in soaking hard hides 18 Washing after coming from the laya- ways 94 Water in cells of hides 178 Wlieel scrubbing 95 Wheel stufting 219 Whitener, Charles Korn's 27(5 the Union 278 risk's 280 White spots in sole leather 89 Wilcox, Pa., cost of wet tan furnace at 2iO Working hides and skins to break the nerve 40 REPORT OP THEEOTSr SKEETL, C. E., ON THE COMPARATIVE ECONOMIES OF wmim VET SPENT m BY THE VARIOUS DETACHED FURNACES NOW IN USE BY THE TANNERS OF PENNSYLVANIA AND NEW YORK. NEW YORK : OFFICE OF THE SHOE AND LEATHER REPORTER. 17 Spruce Street. 1876. BUENING WET TAN IN DETACHED FUENACES. In order to explain and justify the great particularity with which this series of experi- ments have been conducted, it is proper to say that in the suit of Black vs. Thome, in which was involved the merits of the so-called Thompson patent for burning wet tan bark, saw dust, &c., both Profs. Silliman and Thuiston insisted upon the theoretical and practical superiority of the Thompson furnace over those in pubUc use at the time of this patent. Prof. Thurston was compelled to admit, however, that methods outside of the Thompson patent were quite successful, and gave practically all the power re- qaired, but thought, from his observation and experiments at two tanneries, that the Thompson furnace would give about thirty per cent, better results from a given amount of wet spent tan than the furnaces outside of the patent. As this result was known by all practical tanners not to be true, they naturally felt anxious to have the experiments made with more care than Prof. Thurston had pre- tended to exercise. He guessed and estimated too much, and weighed and measured too little, to carry the conviction of his theories, as against the known results in actual practice. Hence it was that J. B. Hoyt and J. S. Schultz, representing the tanners, sought for some expert that should carefully retry the experiments so imperfectly per- formed by Prof. Thurston, and they were greatly aided in this endeavor by Mr. B. E. Isherwood, Chief Engineer of the U. S. Navy. The letter received from him so fully sets forth the grounds of his commendation that it is here inserted with the correspondence and report which follows. . Q X- . . New YoEK, August 17, 1875, 111 East 36th Street. DEAB biE :— I take tne liberty to write you la regard to some experiments which I understand you contemplate, and which I hope you will have made, on the evaporative elliciency of wet taa bark burned in the furnace of a steam boiler. The subject is one of great interest m engineering, which is my apology for thus troubling you - and the problem should be solved in so complete and appropriate a manner as to remove for ever the doubts now resting on it. In my opinion there is no persou of my acquaintance so thoroughly qualified to con- duct such experiments, and ascertain their results, as Mr. Theron Skeel He has all the necessary qualifications of an education, both mathematical and practical and he is an expert experimentahst. He is thoroughly versed in the subject, and his report will command a respect and confidence not easy to obtain for that of any other Whatever experiments Mr. Skeel makes will be devised in a manner to defy hvpercriticism as to the propriety of their results, and his literary ability will enable 'him to present them so clearly, forcibly and full that they will be understood and accepted by all. Should you conclude to have these experiments made, I volunteer the advice that vou aJIow Mr. Skeel to have full power in devising and conducting them. By so doing I am confident you will obtain such results, and in such a manner, as will forever settle the questions at issue. The worst extravagance wiU be to so limit the experiments as to cause the least shadow of doubt to remain. I hope, in the interest of industrial science, that you will turnish Mr. Skeel the means to do justice to both himself and the subject ^ r. '^"'^^ obedient servant, B. F. ISHEEWOOD, Jackson S. Schultz. Chief En gineer U. S. Navy. Tvr^ o New Yoek, Aug. 20, 1875. Mb. Theeon Skeel: , „.-¥^ Sir:— Within a few days I have received a letter from B. F. Isherwood Esq Chief Engineer of the U. 8. Navy, in which he recommends you as a suitable person to test the evaporating power of wet tan bark when burned in furnaces in the front of steam boilers. In view of your conceded ability, in common with other tanners who are interested in the subject above referred to, and particularly as developed by the oontroversv arising out of the suit now pending on the Thompson patent for burning wet fuels we desire that you at once proceed to test, by a series of experiments at several tanneries the comparative merits of the various methods, but particularly those of Thompson' Hoyt, Crockett, and other such modifications of these as in your judgment may tend to throw light upon the general subject embraced in the ''consumption of loei fuels in detached furnaces or ovens." *********** Our wish and instructions to you are, that you make your tests in the most thorough manner, and, when you have finished your work, that you report to us m writing Very truly, (Signed) J. s. SCHULTZ, on behalf of J. B. Hoyt and others. REPORT. 86 Irving Place, New York, Dec. 30, 1875. Jackson S. Schultz, Esq., Nos. 63 and 65 Cliff Street, New York, J. B. HoYT, Esq., and others : Gentlemen — I submit tlie following report of the experiments made in accordance with your letter of instructions preceding. The experiments were made on three forms of furnaces de- signed to burn spent tan in the condition in which it comes from the leaches. The object of the experiments was to determine in which kind of furnace the hot gas developed by the burning of a given quantity of wet tan would evaporate the most water in the boilers attached. The furnace which excels in this respect may be said to be the most economical of hark. This must be distinguished from commercial economy, which depends upon the value in money of the spent tan, the cost of the furnace and of attendance and repairs. In the present state of the art about one-half of the spent tan is thrown away in all sole leather tanneries, for they only use about one-half of all the tan made to make the steam necessary for the whole tannery. Under these circumstances the moiety of the tan has no value in any case, and in some locations is worse than valueless, for the tanners are prohibited by law from dumping the tan into the stream, or where there is no stream to dump it into (as is some- times the case), they are obliged to either cart it away or to erect an additional furnace especially to burn it. The term economy as used in this paper refers to economy in the use of hark only. The economy of any furnace (the term furnace including the whole combination of ovens and boibrs) evidently depends upon : 1. The total heat which would be developed by the perfect combustion of the quantity of tan fed into the oven. 2. The portion of the heat that is developed by the combus- tion that, takes place in the furnace. 3. The portion of the heat developed which is utilized by the boilers. The first condition depeads entirely upon the bark, and is in- dependent of the oven or boiler.-^ The second condition depends almost entirely upon the oven and is independent of the boiler. The third condition depeads both upon the furnace and boiler. In order that any set of experiments should be conclusive in themselves without reference to any conditions but the quantity of tan burned and of water evaporated, it is necessary that a set of ovens should be built of each kind and connected to exactly similar boilers, and that these ovens shall be fed at the same time with the same quantity of tan from the same leach, and that the pressure of steam and the temperature of the feed water shall be the same in each case. Such experiments would be comparative, but are not practicable. In the absence of exactly similar conditions, it is necessary to consider (so far as we are able) all the variations. The experiments described in this report were made in 1875 as follows : Sept. 22 — Crockett furnace, Stevens' tannery, Great Bend, N. Y. Sept. 24— Crockett furnace, Wells' " Southport " tannery, Webb's Mills, N. Y. Sept. 26— Thompson furnace, H. F. Inderlied, BrackneyTille, N. Y. Sept. 29— Thompson furnace. Weed's tannery, Binghamton, N. Y. Oct. 6 — Crockett furnace. Wells' " Southport " tannery, Webb's Mills, N. Y. Oct. 16-17— Hoyt's furnace, Wilcox Tanning Co., Wilcox, Pa. Dec. 9— Crockett furnace, Wells' "Southport " tannery, Webb's Mills, N. Y. Dec. 10— Crockett furnace, Wells' " Southport " tannery, Webb's Mills, N. Y. The plans, and dimensions of the ovens and boilers and the detailed description of the experiments are given in the appen- dices to this report. FUEL. The fuel was in all cases spent bark of hemlock trees, called *' tan." The trees are felled while living and stripped of their bark during the summer season. The bark is piled up in the *If the tan wfere so thoroughly leached and dried as to be fed into the furnace nearly in the condition of perJecUy dry wood it is probable that the combustion would be more nearly perfect, with the same supply of air, than if the same furnace were fed with im- perfectly leached bark. woods after being stripped, and during the winter hauled into the tannery and piled up again until needed for use. The bark is peeled from all sizes of hemlock trees down to about 6 inches in diameter, the largest being about 30 and the average perhaps 15 in diameter. Good average hemlock land will peel about 12 cords of bark to the acre. One man will fell, peel and pile about 1^ cords of bark per day. The bark when originally peeled from the trees, at the same season, has probably nearly the same composition in all locali- ties. This has been found to be true of wood, and therefore inferentially of bark. Li that condition, then, a given weight of bark would probably correspond to a given quantity of heat in all cases. If, however, it is not burned at once, it dries more or less according to the length of time and the circumstances under which it is stored. The time of storing varies in practice from a few weeks to several years, and while sometimes it is stored in large piles and exposed to the weather, at others it is stored in small piles under sheds. After being stored a certain length of time it loses all the water except about 14 to 16 per cent., leaving the balance containing 84 to 86 parts of dry wood and 14 to 16 parts of water.* If more thor- oughly dried than this by exposure in a hot kiln, it will on exposure to the atmosphere reabsoib an amount of water vary- ing from 14 to 16 per cent, with the hygrometric condition of the air. Dry wood, in the sense used in this paper, is under- stood to be wood that has parted with all the water it will when exposed to dry air at a temperature of 110° Centigrade or 230° Fahrenheit. The unit of measure of the bark in this condition (before being ground,) called " chip bark," is among tanners the cord, being a pile of bark 8 feet long by 4 feet wide by 4 feet high. The weight of this volume of bark is variously estimated at from 1,800 to 2,240 pounds, and probably varies within thtse limits with the manner of packing and the weight of water contained. Before leaching the bark is ground in a machine called a " bark mill." The bark in its original condition consists of an outer shell of hard dry substance, analogous to " cort," and an inner ♦I am informed by a gentleman who has had conaiderahle experience in drying wood for manufacture into spools that green wood if cut into fagpots and exposed to the air in eheds protected from the weather, would lose in one year all the water it contained except about 15 per cent., as compared with kUn dried wood at 150 deg. F, The kUn dried wood would reabsorb this 15 per cent, when exposed to the air. layer of a substance containing more sap and more like woody fiber. In the first process of grinding the outer shell grinds much finer than the inner. In some tanneries the whole product from the mill is sifted in a revolving screen, and the coarser part, consisting mainly of the large pieces from the inner layer, is sent back to the mill and reground. The weight of a cord of ground unleached tan (being deter- mined by weighing the contents of several boxes containing exactly 25 cubic feet each) the bark being shoveled into the box, not packed, and struck off with a straight edge, was found to be at the various tanneries as follows : Wells' 2,582 pounds Brackneyville 2,353 pounds Wilcox (fine) 2,418 pounds Wilcox (coarse) 2,284 pounds Average 2,351 pounds The water contained in the last two specimens as compared with the same dried at 110° C. was found to be : Wilcox (fine) 18.1 per cent Wilcox (coarse) I7.O per cent And therefore the weight of a cord of dry ground unleached bark : Wilcox (fine) 1^980 pounds Wilcox (coarse) 1,895 pounds Average 1,938 pounds But at Wilcox all coarse ground tan is sent back to the mill and reground, and therefore the weight of a cord of fresh ground bark will be the mean of the coarse and the fine, or 2,418 pounds, the percentage of water contained 17^, and the weight of the cord of dry bark 1,995 pounds. Probably no sensible error will arise if we assume for all cases the weight of a Cord of dry unleached ground bark = 2,000 pounds. In this condition probably the same weight of bark will de- velop the same amount of heat in all localities, and within the limits of practice the same is true of equal volumes. After being ground the bark is "leached," that is, placed in a wooden leach having a perforated bottom and saturated with warm water for several days. This water percolates through the bark and carries off with it, if the process is continued long enough, all soluble matter. After the soluble matter is supposed to be all out, the water is allowed to drain off and the residue, called " wet spent tan " IS shoveled out of the leaches and carried to the furnace to be burned. A cord of the bark in this condition has been in former experi- ments taken as a unit of measure of the amount of heat equiva- lent to the tan fed into the furnace. In order to test the accuracy of this assumption the whole quantity of tan burned in each experiment was measured and weighed, as in case of dry bark, by shoveling it into a box containing about | cord, striking off with a straight edge, and weighing the contents. The weight of a cord of wet leached tan under these circum- stances was found to be at various tanneries as follows : Stevens' 4,442 pounds Wells' (Ij 4,294 pounds Wells' (3) 4,275 poiinds Weed's 4 270 pounds Wells' (4) 4,260 pounds Wells' (2) 4,225 pounds Brackneyrille 4,112 pounds Wilcox 4,076 pounds Average 4,244 pounds The per centage of water lost by drying* at 110° C. was found to be at the various tanneries : Wells' 63.4 WeUs' (2) 62.8 Wells' (4; 62.8 Wells' (3) 61.5 Stevens' 61.5 Wilcox 61.2 Brackney ville 59.0 Weed's 55.1 *The average composition of bark dried at 80 deg. C. is given by M. Violet ; Carbon 48.6 Hydrogen 6.3 Oxygen 41.8 Ash 8.3 100 If this bark had been dried at 110 deg. C, as was done in the experiments, its composi- tion would have been changed by the loss of 5 per cent, of water, and would have been: Carbon 51.2 Hydrogen 7.0 Oxygen 39.8 Ash 8.5 100 Or of 51.2 per cent, carbon. 1.2 per cent, hydrogen, 44.2 per ceuit. of hydrogen and oxygen in the proportion to form water, and 3.5 per cent. ash. The weight of the water which one pound of the bark in this condition would evapo- rate from 212 deg. F., computed by allowing 15 pounds per pound of carbon and 6^ pounds per pound of hydrogen, will be : Carbon 51.2@15 = 7.68 Hydrogen 1.2@64 = 0.77 8.45 Of this 66-100 of pound of water are latent in gas, leaving available heat 7 9-10 And consequently the weight of the dry portion of the cord : Weed's 1,917 Wilcox ....1,582 Wells' (4) 1,606 Wells' l'3) 1,646 Brackneyville 1,686 Stevens' 1.710 Wells' (1) 1,572 WeUs' (2) 1,572 Average 1,661 Average weight, rejectiDg Weed's 1,625 In order to try the effect of paeting on the weight of the cord, several boxes were weighed containing tan packed by a man (weighing at Wells' about 150 pounds, and at Brackneyville 180 pounds) stamping it down as fast as shoveled in, the top being struck eff with a straight edge as before. The weight of the cord was as follows : Wells' 5,S27 Brackneyville \ . .5,490 Average 5,405 The per cent, of water contained being as before, the weight of the dry portion will be : Wells' 1,950 Brackneyville 2,251 Average 2,100 At Wilcox the whole contents of two leaches were weighed. The weight of a cord at the density of packing in the leach was found to be : Wilcox 5,219 And the weight of the dry portion : Wilcox 2,025 In the experiment marked Wells' (3) and Wells' (4), the tan was used during the first part of the day from the bottom of one leach and during the second part from the top of another. The following exhibits the weight of a cord taken from various parts pounds from 212 deg. Probably no sensible error will arise if the thermal equivalent of one pound of bark dried at 110 deg. C. is taken at 8% pounds of water evaporated from 212 deg. F. The thermal equivalent of a coid should V c in water evapoialcd from 212 deg : 2,000X8.5=17 000 pouurls. Prof. Johnson has made some experiments on dry pine wood giving T% pounds of water from 212 deg. F. No estimate of the water contained is given, but assuming it to have been 20 per cent, (and it could not have been less), there results from his ex- periment : Pounds of water evaporated from 212 deg. F. by pound of pine wood (dry) 9.38 In his experiment, 1 36-100 pound of water were latent in gas, leaving available heat, 8.02. of the leach, the whole capacity being 10 cords, the bottom cord being called the 10th : 1st day, 8th cord in leach, 48 hours draining, weight 4,262 pounds 1st day, 10th cord in leach, 56 hours draining, weight 4,306 pounds 2d day, Ist cord in leach, 24 hours draininsr, weight 4,262 pouuds 2d day, 2d cord in leach, 32 hours draining, weight 4,211 pounds 2d day, 3d cord in leach, 38 hours draining, weight 4 257 pounds 2d day, 4th cord in leach, 44 hours draining, weight 4,290 pounds A sample of bark to determine water was not kept separately for each cord. The weight of a wet cord seems steadily to increase from the top toward the bottom, but not very rapidly, the whole increase being less than 2 per cent. The masses of bark were broken up by shoveling out of the leach, and were all measured at the same density, these figures having no reference to the tightness of packing iu various parts of the leach. The extreme variations of weight of the dry portions, from 1,917 at Weed's to 1,572 at "Wells', would at first seem to point to an error /in measurement. The following exhibits the difference : Wells'. Weed's. Weight of cord of wet tan *4,294 4,270 Weight of dry portion 1,572 1,917— difference 345, Weed's most Water 2,722 2,353— difference 369, Welles' most *The dry green bark, having the same composition in both cases, is, according to M. Violet, made up of : 1. Of a material called cellulose, which has always the same composition. 2. Of an incrusting material which is richer in carbon and hydrogen, and of which the principal constituents are resin, gum, starch, sugar, glucose and tannin. 3. Of mineral matter or ash. The soluble coastituents are wholly or partially extracted, according as the process of leaching is more or less complete. It is possible, then, that the soluble portion was nearly all ex- tracted from the Wells' bark and but partially extracted from the Weed's bark, the pores being filled with water in both cases, but there being more empty pores to contain water in Welles' bark. If this should be true, the balance of the soluble matter may be extracted by thorough leaching, and the dry portion remain- ing should have been nearly the same weight in every case. In order to test this theory a given weight of wet bark was taken, the sample from each tannery boiled for 2^ hours, the ♦Annales de Chimio aad de Physique, vols. xxin. and xxxn. 10 liquor filtered, and the balance dried at 110° C. as before, result of this experiment was as follows : The leach. Stevens 1,710 pounds Brackneyville 1,649 pounds Weed's 1,917 pounds WeUs' (1) 1,572 pounds Wilcox 1,582 pounds WeUs' (2) 1,572 pounds Original weight of Loss of weight by Final weight of dry cord from boiling 2% leached dry hours. .1,667 84 pounds 113 pounds 408 pounds 93 pouQds 98 pounds 148 pounds 157 cord. 1,626 pounds 1,536 pounds 1,509 pounds 1,479 pounds 1,484 pounds 1,424 pounds 1,510 The variations of the weight of the dry boiled portion may be due in part to the fact that the soluble matter is not yet all out, for they were only all boiled the same time, and not until they ceased to lose, as would have been the final test. Enough, how- ever, was done to show that so far as the extremes are concerned. Weed and Wilcox, the measurements are probably correct. A specimen of the unleached bark from Wilcox's was soaked in cold water for 36 hours and boiled for 6 hours, the liquor filtered, and the residue dried at 110° C. as before : Original weight of Loss of weight Final weight of cord dry un- by leaching cord boiled leached bark. and boiling. dry bark. Wilcox (fine) 1,980 341 1,639 Wilcox (coarse) 1,895 366 1,529 Average , 1,937 Screened and reground bark at Wilcox 1,995 354 365 1,589 1,630 This bark would probably have lost more if the process of leaching had been continued for six days, as in practice, in place of 42 hours. Probably no sensible error will arise if the weight of a cord of thoroughly leached bark from the tannery be taken at 1,400 pounds, when dried at 110° C. It appears, then, from these experiments that the average weights are as follows ; Cord of average green r ground bark. Soluble matter 500 pounds 20 per cent Insoluble matter 1,500 ponnds 60 per cent Water, 500 pounds 20 per cent Cord of well leached wet bark from tannery. 000 pounds 00. per cent 1,500 pounds 35.7 per cent 2,700 pounds 64.3 per cent 2,500 pounds 100 per cent 4,200 pounds 100 per cent The experiments do not show what the 500 pounds of extract- ive matter consists of, but only that it is material soluble in hot and cold water. The proportion of water does not increase with the size of the lumps, as was found by drying a specimen of very large lumps from cord. The water contained was shown to be exactly the same as in the fine. A cord of tan thoroughly leached and saturated with water weighs more and contains more water than a cord imperfectly leached.* A cord of fine ground tan weighs more than a cord of coarse ground, as a barrel of meal weighs more than a barrel of corn. THE CKOCKETT FUKNACE. The Crockett furnaces experimented upon consist of an oven of fire brick, constructed near the boiler, and having a set of cone grate bai«s of cast iron. The tan is fed in through doors in the front. The depth of the furnace is limited, as in the ordinary furnace for coal, by the distance to which the fireman can easily throw the tan, to 6^ feet, but may be as wide as is necessary to give the grate surface, and varies in practice from 6 to 12 feet in width. The fire is started (as in every case) with dry wood, and con- tinually replenished until the brick work is hot, after which no more wood is necessary. The frequency of feeding depends upon the rapidity of consumption. When burning at the rate of 7 pounds of dry tan per square foot of grate per hour, each por- tion of the furnace requires to be fed with fresh tan every three- quarters of an hour at least. If there are several doors, each door has to be opened every three-quarters of an hour. At Welles' furnace there were three doors, and some door was opened every 15 minutes. The time of feeding under these circumstances was about 1^ minutes, so that the doors were open one-tenth of the time. If the fuel burned regularly over the grate, the feeding could be less frequent. The crown of the furnace is a segmental or elliptical arch, and the distance from the crown to the grate varies from 1^ to 2i feet in different ovens. The fire bridge is at the back of the grate, and is a continuation of the back vertical wall of the ash *The specific gravity of the material extracted from the bark is nearly 1% times that of water, so that the 500 pounds of material extracted would bo replaced by 330 pounds of water. The weight would be as follows; Before leaching After leaching Soluble matter 500 Solid, matter 1^500 1,500 Water mechanically held between particles 2,250 2,250 Water in pores originally filled with soluble matter 330 Weight of cord of wet tan 4,250 4 080 These are nearly the weights of cord at Wilcox and Weed's. 13 pit. It rises about 1^ feet above the grate, and extends entirely across the oven. The arch over the oven is generally from 2 to 3 feet longer than the grate, and forms the support for the front end of the boilers. The boilers are generally horizontal flue boilers, with two flues ; the products of combustion, after leaving the furnace, passing forward under the boilers, returning through the flues, and finally passing in front to the chimney through a sheot iron connection. The chimney is generally of sheet iron, and is sometimes set directly over the boilers, and sometimes carried on a brick foundation. The main difl&culty in keeping a uniform fire is the compara- tively small weight of fuel in the furnace at one time. If the fire is can-ied on an average 9 inches thick, there will only be in the furnace at one time (if the grate is 6i feet long by 12 feet wide) 800 pounds of combustible. At the rapid rate these fur- naces are generally fired, being, in the case of "Wells' (1), 800 pounds dry tan per hour, this would only last one liour. A fur- nace burning coal at the rate of 10 pounds per square foot per hour would contain coal enough to last 6 hours. The conditions of a tan bark fire, then, in the Crockett furnace, fed every hour, may be imagined by supposing a coal fire fed every six hours. STEVENS' FUENACE AT GKEAT BEND. The performance of this furnace during the experiment indi- cates the economy of the Crockett furnace when forced to the utmost. During the experiment the number of pounds of dry tan burned per hour was : Per square foot of grate surface 10.70 Par square foot of heating surface 1-61 Per square foot of the cross area of flues 258 00 In order to consume this tan the damper and ash pit doors were kept wide open and the furnace fired every ten minutes. The method of firing was first to fill the holes that had burned through, and then to cover the whole surface with a layer of tan about 3 inches thick. The tan thrown in first forms a uniform layer over the surface. It appears to undergo a species of distillation, during which the water is evaporated, the tan maintaining its original brown color. Just before firing, the furnace was a dull red over about half its surface, the color fading out into a black toward the front, and the •surface of the tan was burned through into holes wherever the origi- nal tan was thinnest or the fire hottest, but mostly where the grate had broken away and left large crevasses through which the tan fell into the ash pit. At the instant before firing, the temperature of the gases leaving the furnace was scarcely sufficient to melt silver, and there was no smoke coming fi'om the chimney, but occasion- ally a few sparks. The fireman would now throw in as described the charge of about 300 pounds of wet tan through both doors alternately. Immediately on closing the doors the destructive distillation of the tan commenced, under the combined influence of the heat radiated fi-om the surface of the arch above and of the hot embers on the grate beneath. By looking in through some of the crevasses in the front of the furnace hundreds of Httle jets of white smoke could be seen issuing fi-om the whole surface of the tan. During the process of distillation, wliich lasted about 3 minutes, the smoke and steam which was unable to find an outlet iato the chimney issued in small quantities through the crevasses in the brick work into the fire room, or was forced back through the grate into tbe ash pit. A careful examination of the edges of the crevasses in the brick work showed them to be covered with a deposit of an oily substance, undoubtedly condensed from the smoke, showing that at this time the combustion was imperfect, and that the smoke issuing from them had contauied combustible matter. During the process of most rapid distillation, no air entering the ash pit, combustion must have been entirely suspended, and whatever gases were generated must have passed away un- consumed. Toward the end the crown of the furnace becomes black all over, owing no doubt to the heat absorbed by the water in the tan. Now there are signs of combustion commencing. These are, first, the cessation of the smoke fi-om the crevasses into the fire- room, and little jets of yellow flame replacing the smoke in the furnace. They begin gradually, and in about two minutes cover the whole surface of the tan, which gradually grows red hot and consumes. From the time of the first appearance of the flame, the crown of the furnace gradually grows hotter, and just before firing is red hot over half its surface as before. The appearance of the smoke during the first part of the cycle indicates the presence of combustible gas at that time. Unfortu- nately, the loss of heat by combustible gas does not cease when the flame commences, for although at that time some of the gas is consumed, probably a large part of it, forced from the tan by the heat of the embers below, and issuing into a comparatively cool oven, does not acquire sufficient temperature to consume, even 14 though mixed \vith sufficient aii\ I consider that in the Stevens furnace, fired in this way, probably the whole efi'ect of the gaseous portion of the fuel (about 25 per cent.) was lost. This loss was aggravated by the very thm layer in which the bark was spread over the whole surface, allomng all the water to be evaporated in a few minutes, the volume of gas completely filling all egress from the boilers, thus arresting combustion and alloAving the furnace to cool down below the temperature necessary for the ignition of the gases expelled during the subsequent process. This loss would have been probably almost entirely prevented by closing the ash pit down so as to burn about half as much tan, or by putting in two more boilers, so as to have twice as much area of flue. In either case the effect would be to give an excess of area to the outlet over the inlet of the oven, so that the com- bustion need not cease while the distillation is taking place, in which case the temperature of the oven would be maintained nearly constant, and the gas consumed as fast as expelled. It is also necessary for the combustion of the gas that there should be supplied an amount of air that does not pass through the incandescent tan on the grate. Unless this air is supphed the gas will pass off unconsumed. This air is supphed practically by the holes burned in the fire. The tan, after being dried in the furnace, commences to burn away most rapidly where tan is thinnest or the draft strongest. The layers of bark around this hole do not slide down and fill it, but stand perfectly perpendicular, or even overhang a httle. These holes generally form on the crest of the grate bars, and in a few minutes enlarge rapidly, and finally lay bare the whole crest. They act a very efiicient and beneficial part if not allowed to in- crease too much, but check the fire and cool the oven if left too long without being filled. A description of the performance of a Crockett furnace, when these holes were in one experiment allowed to form, and in an- other when they were kept from forming by fiUing up all hollows with fresh tan before the surface had burned away (marked Wells' 3 and Wells' 2), in which it appeared that with the same rate of combustion, and with the same temperature m the oven, the per- formance of the furnace in the case where the holes were kept open exceeded the performance when the holes were kept shut by more than 26 per cent. In the case of the Stevens furnace at Great Bend, the main 15 cause of the failure in economy was undoubtedly, owing to the high rate of combustion at which it luas forced. CROCKETT FURNACE AT WELLS' TANNERY. This furnace was similar to the Stevens furnace, except that there were 3 boilers, each 42 inches in diameter and 22 feet 6 inches long, with two horizontal flues, 13 inches mtemal diameter. The grate was 6 feet 6 mches deep by 12 feet wide. The boilers had been in use for 22 years and were said to be covered with scales on the inside and the brick work was full of fissures. There were many leaks around the sheet ironwork con- necting the boilers with the stack and in the back connection. The oven was new and in good order. It had been recently built to replace a Thompson oven torn down, being connected with the same boilers. The grates were " cone grates," and were new and in good order. In the first experiment, marked " Wells' (1)," the furnace was tested m the cendition it was found, the rate of combustion being a little more than enough to supply the steam necessary to run the tannery. In the second experiment, marked " WeUs' (2)," the air leaks in stone work and sheet iron work were closed, as far as practicable, with mortar, and the rate of combustion was reduced to the same as at " Weed's," bemg nearly 64-100 pounds of dry tan per square foot of heating surface per hour. AU the holes in the fire were filled, as soon as they commenced to develop, with a shovel full of wet tan. In the third experiment the same pams were taken to stop air leaks, same rate of combustion was maintained, only holes were allowed to form in fire, and the top of the oven was covered with wet tan, which was afterward burned as in the furnaces fed from the top. In the fourth experiment same conditions were maintained as in last, except that cross section of flues were reduced to 2i square feet. EXPERIMENT MARKED " WELLS' (1)." The performance of the furnace durmg this experiment indicates the effect of forcing a Crockett furnace beyond its capacity, the rate of combustion being in pounds of dry tan per hour : Per square foot of heating surface 0 98 Per square foot of grate surface loiso Per square foot of cross section of flues 147!o0 Bemg more than 50 per cent, in excess of the rate necessary to allow perfect combustion. 16 The performance was injured by the cold au- wliich leaked into the flues through fissures in brick work, and particularly by the cold air which had leaked into the chimney by the opening in the sheet kon work around front connection. An opening Avas found here after experiment was concluded exposing 36 square inches. The temperature of the gas leaving the flues, taken in chimney beyond this opening, was 580°, or 270° hotter than the steam, while at Wilcox, at nearly the same rate of combustion, where there was no leak, the temperature of the gas 700°, or 380° hotter than the steam. The inference would be that the temperature of the gas at WeUs' (1) would have been 680° if no cold air had leaked into flue between the boiler and the thermometer. The proportion of air necessary to reduce the temperature 100° would be 16| per cent. The weight of air found in the chimney was 21 6-10 pounds per pound of diy tan by chemical analysis, and, therefore, the air that passed through the flues was 18 pounds per pound of dry tan. The air passmg through the fire was still less than this by an amount that leaked into the fines en route from the furnace to the chimney. The furnace was fed about every 10 minutes through one door at a time, thus making the weight of a charge about 300 pounds of wet tan, the balance of the hourly consumption being thrown in, in occasional shovel's full, to fill up holes. No care was taken ts fill up holes burned in fire. These were so large, just before feeding, as to expose about one square foot of opening for passage of cold air from ash pit through holes in grate bars. The temperature of the gases leaving the furnace, as indi- cated by a piece of metal on the bridge wall, was just sufiicient to melt silver at their hottest. This occurred about midway in the interval of time between the feeding and the burning down of the fire ready to be fed again. The surface of the arch over the fur- nace showed at this time a bright red over about half its surface, faduig out toward the front. As the holes developed in the fire, the color died away, and was a dull red just before feeding. After feeding the color faded away and was invisible for a few minutes, gradually recovering to a bright red just before feeding again. The extremes of temperature of the furnace were then probably 1,000° and 1,900°, and the average about 1,500°, corresponding to about 15 pounds air per poimd dry tan. Tlie general appearance of the furnace was as at Stevens', only less exaggerated. The period during which the tan was not burn- 17 ing was sliorter, and the smoke was never returned into the fire room. The large supply of air was probably mostly due to the holes allowed to bum in the fire. Probably a considerable portion of the combustible gas was wasted in this experiment. The heat unaccounted for in the gas, water and steam was 0.40 pounds of water evaporated from 212°, or about 5 per cent. EXPEEIMENT MARKED WELLS' (2). After the completion of the ;experiment marked Wells' (1), and noticing the injurious effects of the holes burned in the fire, it was determined to try the effect of keeping the holes entirely closed, and at the same time to reduce the rate of combustion to that at Weed's. The outside of the boiler was carefully covered with mortar to prevent any air leaking into the flues. The only air that did leak in was probably between the boilers and the chimney and had no effect on the economy. The surface of the fire was carefully watched, and as soon as a hole began to develop it was closed by opening the furnace door and throwing as quickly as possible a shovel full of tan directly into it. The furnace was divided into three sections, corresponding to the three doors, and these sections were fired every hour, the weight of the charge being 400 pounds of wet tan, the balance of the hourly consumption being used to fill up holes. The fire was kept about one foot thick. The temperature of the furnace was higher than during the previous experiment, and nearly the same as in the succeeding experiment, indicating a smaller supply of air. As no air could reach the chamber in which the gases were gene- rated without first passing through the 12 inches of tan, there could but very httle free air reach them at aU, and they probably passed away entirely unconsumed, entailing a loss upon the fm'- nace of about 25 per cent. The steam formed was only thjee- fourths of that in the succeeding experiment, or indicating a loss of 20 per cent. EXPERIMENT MARKED WELLS' (3). The results of this experiment probably are the maximum for this fuiiiace in the condition v,'hich it now is. The rate of combustion was the same as in last experiment, and the air leaks were carefully stopped, except those in the sheet iron work between the boiler and the chimney. The furnace was fired about every 15 minutes, the weight of the charge being about 300 38 pounds of wet tan, the balance of tlie hourly consumption being- scattered in as the fire seemed to need it. The temperature of the furnace was more nearly uniform, being at the highest sufficient to easily melt silver, and at the lowest a dull red, or about 1,200° and 1,900°, and the mean temperature of not less than 1,650°. I estimated the mean temperature from the comparative time the highest and lowest lasted. The average opening of the furnace doors during the hour was about 7 minutes. The area exposed by the open furnace door for the inflow of air was about 300 square inches, while the average opening of the ash pit doors was about 100 square inches, or about one-third. It appears then that the furnace doors would have passed into the furnace 3 times as much air as the ash pit doors while they were open, but as the furnace doors would only be open about 7 minutes during the hour, would only admit about 30 per cent, of the air admitted through the ash pit. The tempera- ture of the fire when the doors were closed being as high as in any furnace tested, shows that at that time the tan was burning with as small a supply of air as m any case, or 10 pounds per pound dry tan. The weight of air per pound of dry tan, as determined by velocity of smoke, was 16 pounds. A considerable portion of this must have leaked in through the opening in the sheet iron work. The temperature of the furnace is computed from heat : Given up by products of eombustion to steam, taking weight of air per pound of dry tan at 16 pounds, and adding temperature of cbimney, 490 degrees. . . . 1,310° From the thermal equivalent of tan, allowing 0.25 pound for radiation, and assuming products of combustion to take all heat, the supply of air being 16 pounds per pouud dry tan l.SOO'' But the mean temperature of furnace was found to be 1,650°, indicating that 25 per cent, of the air in the flues had not passed through the furnace, leaving the supply of air 12 pounds per pound of dry tan. In this experiment the draft was controlled by nearly closing the ash pit doors. No smoke came from the chimney. The top of oven was covered with tan. This was the most successful experiment made on the Crockett furnace, and the results indicate that the success was mainly owing to the manner of firing, and to the fact the draft was con- trolled by the ash pit doors, in place of by the damper in the chimney, the effect being to make the area of egress larger than the area entrance for the air. The tan on the top of the furnace undoubtedly saved some heat. This experiment being the best 19 performance of the Crockett, should be compared with the best performance of the Hoyt and Thompson furnaces at Wilcox and Binghamton. If the air in the chimney had not been diluted with 25 per cent, of air from the outside, its temperature would have been 650°. EXPEKIMENT MAEKED WELLS' (4). This experiment was made to determine the effect of reducing area of exit for gas. The rate of combustion was the same, the manner of firing was the same, the temperature of the furnace was nearly the same, and the chimney 10° colder. Notwithstanding, the steam generated by one pound of dry tan was 5 per cent. less. The area of flues in this experiment was reduced until they had some influence on the gas flowing from the boiler, and resulted in a small loss of combustible gas. There was some smoke during this exeriment. During the experiment marked Wells' (1) there was an excess of steam formed over that required to run tannery. Duiing the experiment marked Wells' (3) there was sufficient steam formed to carry 60 pounds pressure and run the whole tan- nerry, including heating liquors and all the macliinery they ever ran. The consumption of tan was at the rate of 4 cords in 12 hours, or, allowing 1 cord for banking fires, 5 cords per day, being less than one-half of the bark they used for tanning their hides. MANNER OF MAKING EXPERIMENTS. The experiments were aU made in the same general manner as follows : Tan — The tan was measured in a box at its natural density ; that is, merely shoveled into the box and " struck " with a straight edge. The box was counterbalanced on platform scales, and the weight of tan contained in each box noted in the log. After the furnace had been running a few hours, so that the amount of tan required was known, it was arranged to dehver a boxful every 5, 10, 15 or 20 minutes, according as required. The boxes, under these circumstances, were dumped at exactly the end of these intervals ; that is, if there were required 3 boxes of tan per hour, one would be dumped at the even hour, one at 20 minutes past, and one at 20 minutes before, exactly. The object of this arrangement was to prevent any confusion as to the number of boxes delivered. When, as at Wilcox, there are used sometimes 20 boxes an hour, such an ar- rangement is found to be necessary. The tally of the weight of each box, and the minute at which it was dumped, was kept by myself and the man wlio was in charge of the gang of shovelers. WaUr in tan — The water in the tan was determined by drying several specimens of 200 grammes each, taken from a sample of one quart brought from the tannery in a hermetically sealed glass jar. The tan was dried by my associate, Prof. J. K. Rees, of Columbia College, m an air bath at 110° Centigrade. The method of obtaining the sample of one quart was as follows : There was provided a tin case with a hd and lock. A double handful of tan was taken from each boxful of tan as weighed upon the scale and thrown into the tin case. The case was kept locked except when opened to receive samples. At the end of the day there would be collected in this case from 40 to 200 double handfuls of tan, being collected in equal portions from every boxful of tan used. At the end of the day the tan in the case was shaken well up and then spread out upon a table and divided into equal small parts, alternate small parts being taken and the balance rejected. The original easeful was thus reduced by successive divisions (one half being rejected each time) to one quart, when it was carefully placed in the jar, sealed, labeled, and sent to New York by express. Water — The water pumped into the boiler was all measured in casks, the weight contained by the casks, weighed on the same scale as the tan, having been originally determined. There were generally three tiers of casks, the lower one being connected with the pumps and acting as a reservoir, the middle one acting as a measuring cask, and the upper one receiving the supply of water and being provided with an overflow at the top and a plug in the bottom. The middle or measuriug cask also had a hole in the bottom and a plug. The mode of operation was as follows : The man in charge of the water would, when the measuring cask was empty, put the plug in the bottom and pull out the plug from the upper barrel, the water immediately commencing to flow from the iipper into the measuring cask. When the measuring cask was full, he would put the plug in the upper barrel, and after a few seconds, when the surface of the water had subsided to the level of the overflow hole, would pull out the plug in the measuring barrel and allow the water to flow into the lower barrel, whence it would be pumped into the boilers. The same precaution was taken to avoid con- fusion by emptying barrels at exactly even intervals, as in weigh- ing tan. Water entrained with steam — This was determined by a special 31 apparatus designed for the purpose and carried around to all the tanneries tested. It consisted of a worm, through which a small portion of the steam coming from the boiler was passed, exposed to cold water on the outside. The measurements taken were : 1. The weight of water coming from worm per hour being the sum of the steam and water coming from the boiler into the worm. 2. The weight of water passing over the outside of the worm, which carried away all the heat abstracted from the water and steam. 3. The temperature of the water before and after passing the worm, the temperature of the water dehvered from the worm, and the pressure of the steam in the boiler. These three measurements supply all the data necessary to determine the amount of water entrained with the steam. The weight of water passing the outside of the worm was determ- ined by noticing the head of water over an orifice in the bottom of the box in which the worm was, necessary to force all the water through. The volume of water which would be delivered by this orifice for each \ inch increment of head had been previously determined, and was as follows : CUBIC FEET OF WATEE DELIVEEED PER HOTTR FEOM OBIFICE IN BOTTOM OF TAIJK AT VAEI0U3 HEADS FEOM 16 INCHES TO 25 INCHES, AT A TEMBEEATUEE OF 72 DEGBEES F. Head. Cabic feet water. 25 inches 39.60 2434 inches 22 24% inches 02 24% inches 38.82 24 inches 62 23% inches 42 28% inches 22 23% inches 01 23 inches 37.80 22% inches 60 22% inches 39 22% inches 18 22 inches 36.98 21% inches 77 ^1% inches 55 21% inches 34 21 inches 13 20% inches 35.91 20% inches 69 Head. Cubic feet water. 20% inches 35.47 20 inches 26 19% inches 05 19% inches 34.82 19% inches 59 19 inches 36 18% inches 13 18% inches 33.90 18% inches 68 18 inches 45 17% inches 21 17% inches 32.98 17% inches 74 17 inches 50 16% inches 26 16% inches 02 16% inches 31.78 16 inches 53 The figure given in the log is the " head of water in tank." By entering this table with the head, the volume of water correspond- ing can be determined.* *It is believed that the idea of determining the water entrained with the steam by condensing a small portion continuously in a worm and weighing and measuring all quantities, originated with Mr. J. D. Van Buren, Jr. Temperatures— The temperatures, when below 600°, were taken by a thermometer. Above 600°, they had to be approximated to by means of the melting point of metals. Specimens of the same piece of metal were used at all furnaces, and the results are therefore fairly comparative. Method of proceeding— The engmeer generally took charge of the firing, and conducted it in the manner he supposed best cal- culated to produce the best result. As all of the engineers seemed to feel considerable pride in havmg their furnaces do well, I have reason to suppose each did his best. Supervision— 1 was present at the furnace during the whole of each experiment, never leaving it for a single instant, and had a complete supervision of all operations during the whole time. Ashes and re/use— These were determined by raking out the fire and commencing with the tan that had been weighed (in Stevens' and Wells' 1), and by weighing the ashes and refuse dry at the end of experiment. The ashes were found to be so small a percentage, and so much mixed with unconsumed tan, that the attempt to measure them was given up after these experiments. In all others the fire was left at same condition at end as be- ginning, i. €., Thompson and Wilcox furnaces full, and Crockett average thickness. THOMPSON FUKNACES. These furnaces are built in some respects as described in the patents of Moses Thompson, as interpreted by the court. They consist of a series of ovens arranged in pairs, each pair of ovens with the boilers attached being complete in itself. The ovems are built of fire-brick, generaUy from 4 to 4^ feet in diameter and from 10 to 12 feet long. The crowns of the ovens are semieire-ular, and the grates are in the horizontal diameter. The ovens are fed with wet tan through two opem'ngs in the top of each oven. These openings are about one foot in diameter, and so placed m the top of the oven as to best distribute the tan uniformly over the grate. They are supplied with iron covers, but except when starting or burning down the fires these covers are not used, as the tan, kept two feet deep all over the fire room floor, effectually seals these openings. The tan is fed as often as in the judgment of the fireman it is required. When about to feed, he first breaks down the layers of bark which have dried and baked hard over the top and in the feed hole, and then with a bar spreads out the mass of embers and ashes left from the tan last fed in, and finally shovels into the oven all tlie bark that will nm into the feed holes, and ends by filling all up and tramping down the bark into the hole, and covers the top with about two feet of wet tan as before. So far as in the method of construction and operation, I do not understand that the representatives of Thompson make any claims to novelty. Their peculiar claims are as follows : The grates are made of fire brick and are 2| inches wide on top and have a space between them i inch wide, the total area of openings between the bars for the admission of air being less than 20 per cent, of the total grate surface, while in the ordinary forms of grate for coal it is about 33 per cent. The space between the bars inch wide) allows a small amount of tan to run through, partly from its own weight, during the whole process of combustion, but mostly while the fire is being stirred preparatory to being fed. The whole amount that runs through is, however, a very inconsiderable proportion, and would scarcely be felt if it were lost. I do not think it can exceed 10 per cent, in either of the furnaces experimented on, and was probably much less. The amount that runs through, to a certain extent, regulates itseK. It falls into a second oven, built of fire brick, taking the place of the ordinary ash pit. This oven is double for each furnace, the dividmg wall being necessary to sup- port the fire brick grates. In the furnace at Binghamton they were each 22 mches wid^ and 12 feet long. All the air that enters the oven through the grate passes through a small register in the ash pit door into the ash pit, and may then rise through the grate into the furnace, or may pass along under the grate over the glow- ing surface of the embers in the ash pit. The amount of air reach- ing the embers in the back end of the ash pit is necessarily small. The embers falling through the grate slowly accumulate in the ash pit, not consuming as fast as they pass through, until the top of the pile of embers touches the bottom of the grate bar and pre- vents the fallii^g through of any more. During the time the embers are accumulating they only fall through very slowly, perhaps two or three a second. When the embers are accumulated in the ash pit nearly up to the grate bars, the whole surface of the mass of embers, brick work and gxate bars has a very high temperature, perhaps 2,000° F. The reason for this is, I conceive, not on account of the quantity of tan consumed there, or on account of the perfection of the combustion, but because the heat radiated from the embers is not carried away. Only a very small quantity of air circulates through the ash pit under these circumstances, and as all the ash pits in the group, except the two outside ones, are surrounded by others equally hot, but litth heat is lost by radiation. When, on the other hand, the surface of the embers is six or eight inches below the under side of the grate bars, the tempera- ture of the gas at the back end, after passing over the whole length of the ash pit, is not siifficient to melt lead. The other peculiarity of the Thompson furnace, as built at Binghamton or Brackneyville, is the contraction and combination of the outlets for the products of combustion fi-om each pair of ovens. The inventor claims that by contracting and combining the flues leading from the furnace to the boiler, any combustible gas coming from one furnace wiU be consumed by the excess of oxygen in the products of combustion coming from the other, or, in the words of Prof. Silliman, "the gases from the two furnaces may mingle and consume each other." In order that this may take place these three conditions must simultaneously exist : 1. There must be combustible gas in the products of combus- tion of one furnace. 2. There must be an excess of oxygen in the products of com- bustion of the other. 3. There must be a sufficiently high temperature in the mixed gas (about 1,500°). There was no provision for the admission of air into the com- bustion chamber of either the Thompson furnace at Binghamton or Brackneyville other than that which found its way through the oven without uniting with the incandescent tan— that is, that passed through an oven 10 feet long filled with tan at a tempera- ture of nearly 2,000". If there were any combustion taking place in this chamber I judge there must have been some appearance of flame there. There was a small hole drilled iii the door of the chamber of the furnace at Binghamton (Weed's) which allowed an observation of the whole interior at any time without opening the door. The whole interior was nearly always perfectly clear. Occasionally a Kttle flame came out of the oven inlo the chamber. weed's FUliNACJE AT BINGHAMTON. The experiment was made on this furnace by allowing the engi- neer to take entire charge of the method and quantity of firing, he proceeding as he said he had found by long experience to be the best way. The tan was brought from the leaches and dumped on the fire room floor, where it was kept about two feet thick the whole time. The fireman fired the oven without any apparent system, the average number of times each oven was fired being, including both holes, twice every 3 hours or 8 times during a day of 12 hours. Sometimes both feed holes were fed at once m one furnace of the pair, sometimes one feed hole in each was fed, and sometimes both feed holes in each furnace during the same hour, but generally one feed hole in one oven in one hour and the opposite feed hole in the next oven during the next hour, the feed holes nearest the boiler being fed every four hours, and those farthest fr-om the boiler every two hours. The ash pit doors were arranged so as to expose an area of nearly one-third square foot for each oven, or one-sixth square foot for each ash pit, and were not changed during the experiment. One ash pit was raked out partly, the other being nearly frill of incandescent embers. There was scarcely any smoke issuing at any time from the chimney, it being just perceptible occasionally. The rate of combustion remained nearly constant during the whole day, and was nearly 65-100 pounds of dry tan per hour per square foot of heating surface. The tan on being fed through the feed holes into the oven imme- diately commenced to give off vapor fr-om its surface, and, as soon as the immediate surface was dried, to undergo a species of destructive distillation giving off combustible gas. This gas accumulated in the furnace apparently faster than it was carried away, for the smoke would, just after firing, return mto the fire' room through the tan packed into the upper part of the feed hole. The fire room was continually frill of smoke. Part of this came from the combustion of the tan when heaped around the sheet iron work of the front connection, and part of it from the destructive distilla- tion of the wet tan on the top of the ovens, the lower layers being found perfectly charred, but I am of the opinion that part came fr'om the oven back into the fire room. The gas from the furnace, after passing into the combustion chamber, passed forward under the boilers and returned through the tubes into a sheet iron front connection, thence into the stack. The boilers were unprotected on top and had steam drums. Tlie tan on being fed into the furnace immediately spread out into a cone, the angle at the vertex being nearly 90 degrees, reaching from the feed hole to the grate. Just before feeding the surface of the oven would be a bright red all over, which would gradually cool down to a very dull red in that part of the oven nearest the feed hole last fed. The weight of the charge of wet tan fed in was nearly 300 pounds. The combustion seemed to take place entirely on the surface and to reduce the volume of the cone by equal decrements of volume from all parts of the surface, to a very obtuse cone about 60 inches in diameter and 24 inches high. During the process of combustion the oven would grow steadily hotter to the end, and would be, Avhen fed again, a bright red heat, probably about 1,800°. Silver exposed in the combustion chamber was readily melted at all times, sometimes, however, a little sooner than at others. The shortest time was about 30 seconds and the longest about 3 minutes required to melt a silver "dime." A piece of silver, however, hung on a chain and suspended in the furnace bypass- ing the ends of the chain through the two feed holes, the posi- tion of the coin beicg about midway between the feed holes and between the grate bars and the crown of the oven, thus being exposed to the direct action of the flame in the furnace and of the radiant heat from the tan, was not melted, although exposed during the whole experiment. This must, I think, have been because at that point the products of combustion of the tan from one cone were diluted with the air which would afterward be partly consumed by the tan of the other cone on its way to the chimney. There was a perceptible variation of the color of the brick work of the arch, when the tan in both coues was con- suming, from a bright red at the end nearest the boilers to a dull red at the end farthest from the boilers. I think a coin exposed in the oven between the second cone and the combustion cham- ber would have been melted as easily as in the combustion chamber, although this is only an opinion. The fact that the temperature was higher after passing the second cone than before shows that there was a greater excess of air in the prod- ucts of combustion before passing the second cone than after- ward, and suggests the idea that several successive cones of in- candescent bark (which would be the result of four or more feed holes, as in the Hoyt furnace), might still further reduce the excess of air, and therefore increase the temperature of the gas. The time during wliich. distillation only is taking place, that is, before the surface of the cone becomes red, does not exceed five minutes, but it is probable that the tan is only dried and coked to a small depth during that interval, and that the continued distillation goes on from the outer layers of the cone from the commencement until near the end. On raking away the outer surface of the tan during the early part of the process, the fresh, green undried tan will be found underneath. All brick and ironwork around passages for products of com- bustion from oven through combustion chamber were nearly air- tight. Only an insensible quantity of air can have leaked into the flues and mingled with the gas, en route, until the back con- nection is reached. This was of sheet iron and may have leaked considerable air, and also the front connection may have leaked some air. The gases on reaching the back connection had sufficient tem- perature to heat a small spot on the cast iron doors to a dull red heat in the dark. The amount of air found per pound of dry tan in the products of combustion was (by means of the velocity of smoke in the chimney) 10^ pounds. The relative amounts of carbonic acid and free oxygen in the products of combustion by volume, in per cent, of the dry gas : Carbonic acid 11.1 Free oxygen 10.6 The heat developed was (see table), (13-100 being allowed for radiation per pound of dry tan), 7^ pounds of water requiring 6 pounds of air. If the air in excess is 10.6-11.1 of the car- bonic acid, the air supplied per pound of dry tan would be 21.7-^11.1X6=11.7, or nearly a coincidence. If this air had all passed through the combustion chamber, the temperature could only have been (calculated from the) Elevation of temperature of 10% pounds of air, 1 pound of fuel and 1.22 pounds of steam, the air and fuel beinp supplied at 70 degrees and the stoam at 212 degrees by the available heat in the pound of dry tan being 7%— 1.44=6.06. . .1,800" Elevation of the products of combustion being 10% pounds air, 1 pound fuel and 1.22 pounds steam from the temperature of the chimney 510 degrees by the addition of the heat abstracted by the eteam and radiation being 4.43-h.l3=4.56 1 giQo The temperature of the furnace being sufficient to melt silver readily (2,000°), would seem to show that an amount of air equivalent to 10 per cent, of the products of combustion, or 1 4-10 pounds of air, had leaked in, leaving the pounds of air per pound of dry tan which passed through the furnace 9 1-10, or nearly 28 the same in proportion to the heat developed as was found at Wilcox, or li times that actually necessary for perfect combus- tion. It must be acknowledged that this furnace was injured by 10 per cent, of cold air leaking into the flues between the com- bustion chamber and the chimney. Notwithstanding this excess of air there is an amount of heat equivalent to 1 1-10 pounds of steam which Avas not developed by combustion, being about 12 per cent, of the heat in the tan or 25 per cent, of the heat realized on the steam in the boilers. The cause of the incomplete combustion was probably partly due to the small supply of air, for it has been found that in order to burn all the combustible gas coming from bituminous coal in an ordinary furnace, the products of combustion must be diluted with 40 per cent, of their volume of air. In the case of the wet tan at Weed's furnace the products of combustion of the tan in air were already diluted with 40 per cent, of their volume of steam, and therefore in order that the proportion of consumed gas and the nitrogen and water diluting it should be the same as in the case of bituminous coal, the supply of air must be 1| that actually necessary for combustion. There is a way in which the performance of the Thompson furnace is sometimes injured, and in which many of the earlier Thompson ovens that did not succeed were probably injured, that is, by a too great contraction of the flue leading from the oven to the combustion chamber. The effect is the same as on the Crockett furnace at Great Bend. The effect of the contrac- tion at Binghamton will be considered further on. These outlets were arranged as shown in the plans and had an area of 3 6-10 square feet for each pair of ovens, being 1-23 the grate surface. The cross section of the tubes in one boiler was 2 8-10 square feet. The temperature of the gas on leaving the furnace was nearly 2,000^^, and at the entrance to the tubes 1,000°. The volumes of gas were then in the ratio of 5 to 3, and the area of the passages in the ratio of 4 to 3, indicating that the passage from the furnace to the combustion chamber might have been enlarged at least 1-4 with benefit to the boiler without reference to the combustion. THOMPSON FURNACE AT BRACKNEYVILLE. This furnace was similar to the one at Binghamton except that there were two flue boilers, each 3 feet 9 in diameter and 20 feet long, with two flues in each boiler 12 inches in diameter. Only 3 of the 4 ovens were in use, the fourth being bricked off by a 39 brick wall in the opening into the combustion chamber. I had no means of knowing how nearly air-tight this wall was. Ths average rate of combustion was 73-100 pounds of dry tan per square foot per hour, but as in one boiler it was 97-100 and in the other 49-100, the average does not measure the relative economy. Silver could be melted in the combustion chamber (the one connected to the pair of ovens) but could not he introduced into the oven. The performance of this furnace was in every respect similar to the one at Binghamton, except that as the rate of combustion was only one-half as much per square foot of grate the ovens were only fed half as often. There was no system of alternate feeding, and no changing of the ash pit doors. The furnace was not in as good repair as at Binghamton. The pounds of air per pound of* dry tan were found to be 18, by the velocity of the smoke in the chimney, and by the analysis of gas as before, 17 9-10 pounds. Assuming the 18 pounds of air as nearest correct we find for the temperature of the furnace, computed as before : . From thermal equivalent of tan 1,320° From temperature of chimney and steam liSSO? 1,3352 From which may be computed the proportion the air found in the chimney bears to the air passing through the furnace, in order that the combustion chamber may have a temperature of 1,800°, and the weight of air that passed through furnace : Pounds of a'.r per pound dry tan 12 Katie of air necessary to air supphed 100 :175 The weight of air leaking into the flues between the oven and the chimney was 6 pounds per pound dry tan. HOYT FURNACE AT WILCOX. This furnace consists of two pairs of ovens, each pair of ovens being connected with 3 horizontal flue boilers. Each oven, with its boilers, is entirely independent of the other, each being fur- nished with a separate feed pipe, steam pipe, water tank, safety valve and injector. The only things in common between the two ovens are the fire-room and the chimney. The chimney is of brick, 107 feet high above the grate. The ovens are each 6 feet wide and 16 feet long. The grates are of iron, the width of the bar being 7-16 inches and of the space 7-32 inches. 30 The ash. pits are the entire width of the grate and entirely open in front, no doors being provided. The distance from the under side of the grate bars to the bottom of the ash pit is 4 feet 9 inches. This great height allows a double current of air to form in the ash pit, the cold one enter- ing at the front near the bottom, passing toward the back end, becoming gradually warmed by the radiant heat from the grate, rising and returning close under the grate, part entering through the grate to the ovon, and the balance finally passing out of the ash pit at the front at a temperature of 300°, Under these cir- cumstances the temperature of the ash pit is about 200°. If the furnace is so far closed as to prevent the return current of air, that is, if the opening is reduced from 24 square feet to ^ of 1 square foot, the temperature of the ash pit rises to about that of the Crockett furnace, 500°. " When the front is open there is a small loss, due to heating the air which returns to about 300°. There is no contraction of the flue from the oven to the space under the boilers, the opening being the full width of the oven. There are four feed holes, each one foot in diameter, in each oven. The tan is fed in through these holes as it burns down, and the holes sealed by wet tan kept all over the floor about two feet deep. The bark is brought about 250 feet by a conveyor from the leaches, and may be delivered at any point on the floor by open- ing a suitable shoot. This furnace was the most complete in all its appurtenances, being of originally the best design and in the best condition of any experimented upon. The boilers were new and tight, the brick work sound, and all parts of the boiler and smoke connec- tion protected from loss of heat by radiation. The chimney was of brick. There were dampers in the flues leading from the boilers to the chimney. The cross-section of these flues was 4 square feet each. In the case where the most tan was burned the damper was kept wide open, and in the case where the least was burned it was kept at an angle of 45° in the pipe, the effect being to reduce the area to about 2 square feet. The pounds of dry tan burned per hour were respectively 1,000 and 750, or a proportion of 6-10 and 4-10 square inches to one pound of dry tan per hour. This opening was not the con- 31 trolling section in the first case, although it was in the second.* The performance of the furnace during tlio first experiment^does not correspond with the maximum, which might be 25 per cent, more, or 1,250 pounds of drj tan per hour, or | of a cord. The draught was checked in this experiment by a thick bed of ashes which had been accumulating on the grate without being raked out for 10 days. During this time the ashes had accumulated 8 inches to 12 inches deep. The other furnace had not been raked out for 4 days. No ashes or embers fell through the grate at any time. The ash pits were raked out in expectation that some would collect, but were found perfectly clean at the end of the experiment. It is customary to rake out the furnace through the 8 doors provided every fortnight. If it were required to drive the furnace to its utmost it would be necessary to rake them out every week at least. The action, manner of feeding, and appearance of the Hoyt furnace in both experiments is very similar to the Thompson furnace already described, except that the temperature of the oven was more nearly uniform, and there never was any smoke forced back into the fire room through the feed holes. The fires weie watched through the small registers provided in each furnace door, and were filled up when burned dovm. They were generally allowed to burn down lower, L e., further from the crown of the furnace than at Binghamton or Brackney- ville, the greater height of the furnace, 6 feet in place of 4^ feet, allowing this. In this connection it must be remembered that while the rate of combustion per square foot of grate surface was at Weed's the same as at Wilcox (2), and therefore the rate of com- bustion per square foot of superficial area of the cones of tan the same, the actual weight of tan in the furnace undergoing the processes of drying and coking was nearly 2| times as much at Wilcox as at Weed's, and therefore the performance of the fur- naces, so far as all phenomena regarding the intermitted action of the drying and coking are concerned, are not comparative. There was no smoke coming from the chimney at any time during the experiments. *The openings of 6-10 and 4-10 square inches for one pound of dry tan borned per hour are equivalent to 8-10 and 6-10 square inches, with a chimney 80 feet hiijh, and having a temperature of 6C0 degrees inside and 60 degrees outside, as in the case of Wells'. 3» A silver coin exposed in the back end of the oven melted nearly as soon as at Weed's, in about 60 seconds. Much of the air for combustion came through the registers in the furnace doors, for although these registers, except for a few seconds when looking at the fire, were kept shut, they were only iron casting, and must have leaked considerably through the badly fitting joints. I do not consider that the air leaking in here did any harm, but acted as efficiently as if it had come through the grate. When these registers were opened to examine the fire, the surface of the heaps of tan appeared to be covered with about equal portions of black and red cinders, and would begin tp scintillate and grow rapidly red when the air from the register touched it, showing that at that part of the furnace at least, the oxygen in the air surrounding the heaps of tan was reduced below the point of dilution necessary to insure a rapid com- bustion. A considerable amount of heat was lost by radiation from the oven doors. There were 8 of these doors to each furnace, and they all became a dull red in the dark over about 1 square foot of their surface, the atmosphere outside being 30°. The labor of firing at this furnace was very small, owing to the convenient arrangement for delivering the tan on the fire room floor. One man fired usually both furnaces and tended to the water during the day, thus handling usually 10 cords, or 40,000 pounds, of wet tan in 12 hours. If the temperature of these ovens as actually measured be compared with the calculated temperature by the two methods as before, taking the air at 10 pounds per pound of dry tan, we have the following : Wilcox (1) Wilcox (2) Temperature of oven computed from the known weight of air and the thermal equivalent of the tan 2,060" 2,080° Temperature of oven computed from the heat given up by products of combustion to steam and addiuf? temperature of chimney. . . . 2,050° 2,080° 2,055° 2,070° Average 2,060° This temperatiy^e is a little in excess of that estimated fi-om the melting point of silver, showing that no air can have leaked into the flues between the oven and the chimney. The air for combustion was then 10 pounds per pound of dry tan, being 1 40-100, that actually necessary for combustion, or 40 per cent, of " air in excess," being less than at any other place I 33 where the combustion was perfect. I think this may be due to the long oven and 4 cones of tan, by means of which the air in the furnace is intermingled, and each particle brought in contact with surface of tan. LEACHED BAKK. Wood (and inferentially bark) is said by M. Violet to consist of a fibrous substance called "cellulose," which is insoluble in water, surrounded by a material which is richer in carbon and hydrogen. This encrustmg material consists mainly of sugar, starch, gum, resin, glucose and tannm. All of these, except the resin, are soluble in hot or cold water, and are probably wholly or partially extracted- in the process of leaching. They are all compounds of hydrogen, oxygen and carbon, but being rich in oxygen will develop by combustion but a small amount of heat. On the other hand, the resin, which is per- fectly insoluble in water, and must remain entire in the bark after the most thorough leaching, contains no oxygen, and has a thermal equivalent of nearly 22 pounds of water evaporated from 212°, or about three times as much as the soluble constituents. It would appear then that the thermal equivalent of leached bark must be more than of green or unleached bark. The average thermal equivalent of the soluble constituents of the bark is 6^ pounds of water evaporated from 212°, and of the unleached bark (as has been aheady determined), 8i pounds of water evaporated from 212°. There will be extracted from a cord of unleached bark in the process of leaching, if thoroughly done, 600 pounds of soluble matter, and the remainder will weigh 1,400 pounds when dried at 110° C. If the thermal equivalent of a pound of the bark as leached at the tanneries m the diiferent experiments, be calculated on the basis that the original equivalent was 8^ pounds, and that a cord of leached bark has lost the balance of its actual weight, and 2,000 pounds of soluble material having an equivalent of 6| pounds, we shaU find for the thermal equivalent of each bark m pounds of water evaporated from 212° by one pound of bark dried at 110° C. : Stevens' 8.9 Wells' (2j 9.0 Wells' (1) 9.0 Wilcox (1) and (2) 9.0 Brackneyvilie 8.9 Wells' (3> 8.9 Weed 8.6 Wells' f 4) 8.9 This would be the weight of water evaporated or the weight of steam formed in the boiler by the combustion of one pound^^of ta a 34 if the combustion in tlae oven were perfect, and if tlie boiler sur- face were sufficiently extended to reduce tlie jDroducts of combus- tion to the same temperature as the outside air, or about 60°. It wiU be seen that only about one-haK of this amount was evaporated in any case, and generally less than one-half. There are four principal reasons for this discrepancy : 1. Water in the bark. 2. Imperfect combustion. 3. Radiation. 4. Heat carried away in the chimney gas. The first of these is enthely independent of the oven or boilers, and if the proportion of water to bark were the same, might be neglected in every case without affecting the comparison. Unfor- tunately the proportion of water varies in every case. The water put into the oven with the bark has to be evaporated, and absorbs the same amount of heat in being evaporated as though it were put into the boiler. It also lowers the temperature of the oven, thus injuring the effect of the heating surface. It also dilutes the au* entering the furnace, so that probably the wetter bark wiR require a larger excess of ah for equally perfect combustion. The heat in a pound of dry bark that is available, then, is the total heat given above reduced by the heat necessary to evaporate the water in the bark, and to superheat it to the temperature of the chimney (see table) and wiU be : Stevens' 6.9 Wilcox (1) 6.8 Well«'(l) 6.9 Wilcox (2) 6.9 Brackneyville •• . .7.0 Wells' (3) 6.9 Weed 7.0 Wells' (4) ! 6.9 Wolls'(2) 7.0 This is the weight of water that might he evaporated from the boiler by each pound of dry tan.* INCOMPLETE COMBUSTION. Generally in all cases a portion of the heat, about 5 per cent., is lost by incomplete combustion. No analysis of the chimney gas has been made in these experiments that will show how per- fect the combustion was. It can only be inferred from the amount of heat accounted for in aU other ways, probably being *The injurious effect of a small proportion of water in fuel is much less than is gen- erally supposed. A mixture of 100 parts, containing 13 parts of wood and 87 parts of water, will develop sufficient sensible heat to raise the products of combustion to t he temperature necessary for ignition, about 500 degrees. The same is true of a mixture containing 7 per cent, of charcoal and 93 per cent, of water. at least 2| per cent, in the best case (Hoyt's furnace at Wilcox), and much more in the worst. RADIATION. This loss depends upon the form, arrangement and dimensions of the furnace and boiler, the absolute amount being in general proportioned to the surface of brick or stone work exposed. All the furnaces must have suffered considerably fi'om radiation, but if we neglect the heat radiated by the brick work over the oven, which is utihzed in partly drying and heating the tan in all fur- naces fed from the top, all the, furnaces were injured probably nearly ahke. Wells' 2, 3 and 4 being injured most by radiation from brick work, and Weed most from radiation from sheet iron work in back connection, and Wilcox by radiation from furnace doors.* CHIMNEY GAS. The heat carried away in the chimney gas amounts to 30 per cent, in WeUs' (1) and 15 per cent in Weed's. It depends upon two items, viz. : 1. The excess of temperature of the chimney gas over the out- side air. 2. The weight of the gas in comparison with the weight of the fuel. The nearer the temperature of the gas is to the temperature of the atmosphere, the less heat wiU be carried off in the gas. It is the duty of the boilers to reduce the gas to the temperature of the chimney from the temperature of the furnace. If the cMmnies have the same temperature the boilers may he considered equally efficient, whatever may he the extent or arrangement of their surface, provided no heat is lost by radiation, and no cold air leaks into the flues fi'om the outside. AU the boilers tested were injured by a certain amoimt of air which leaked into the flues fi'om the outside, generally through the fissures in the brick work or through tlie joints in the sheet iron work. Probably Stevens' and Wells' suffered most from this cause. At these furnaces the stone and brick work was old and fuU of fissures. During the many years they had been in use the alternate contraction and expansion of the walls had forced out the mortar fi'om the joints. During some stages in the combus- tion smoke issued from these fissures, showing that there were open- *The surfaces exposed for radiat ion were (iron work) : Weed, surface bark connection 50 square feet gas inside 1,000" outside 80" Wilcox, surface furnace doors 50 square feet gas inside .... 2,000° outside .... 30 iiigs through the wall, and that the air must flow in when the pressures were reversed. Brackneyville was nearly tight in the brick work, as were "Weed and Wilcox, but all these were injured by air leaking in through the sheet iron wotk around the back connection. I have no means of estimating the amount of air leaking in through the flues, but should consider that it may have been in- sensibly small at Wilcox. In addition to the air leaking into the flues some air leaked into the chimney between the boiler and the thermometer. This air had no effect on the economy of the boiler, but only reduced the temperature of the chimney and injured the draught. The tem- perature of the chimney, as measured by the thermometer, cannot be taken as a measure of the efficiency of the boiler surface. In WeUs' and Stevens' in particular there were lar^e cracks around the junction of the smoke stack with the boiler. The leakage of air into the chimney had no effect upon the . amount of heat carried away by the chimney gas, the temperature being lowered as fast as the weight was increased. WATEE ENTRAINED WITH STEAM. The measurements taken to determine the water in the steam are given in the appendix. The results are as foUows : Per cent, of water in steam. Pounds per hour. Wells' a) 1-4 33 Krackneyville 7.9 95 Weed 3.4 188 WeUs' (2) 3.5 55 Wilcox, superheated. . .■ • 24° The close approximation of the absolute amount of water car- ried from the boiler in the two experiments at Wells' suggests the idea that this water was due to some condensation of the steam after it had left the water in the boiler as dry steam. There was considerable surface exposed to the cold air in every case, being generally the surface of the steam drums and pipes, and in some cases the tops and ends of the boilers. The amount of surface in each case can be approximately com- puted from the plans accompanying this report, and was as foUows : ■Yyella' 40 square feet Brackneyville 130 square feet deed's 250 square feet Wilcox (to atmosphere at 70 degrees) 60 square feet Wilcox (to gas in furnace at 2,000 degrees) 50 square feet 37 And therefore the pounds of water entrained with the steam for each square foot of surface exposed per hour : Wells' (2) 1.325 Wells' (1) 0.825 Brackn ey ville 0.731 Weed'H 0.752 A perfectly clean steam pipe fiUed with steam at 60 pounds pressure, and exposed to the still air at 80° temperature will con- dense steam at the rate of three-fourths of a pound per square foot per hour. The close agreement of the weight of water entrained with the steam, and the weight of water that must have been condensed by the cold air on the outside of the pipe, leaves no escape from the conclusion that the loater in the steam was entirely due to condensa- tion in every case. As far as the ill effect of a certain proportion of water on the steam when used in an engine for heating liquor or other pur- poses is concerned, it can make no difference whether the water has been condensed fi-om the steam or whether it is carried from the boiler as ivater, without ever having been steam at all ; but as far as the heat abstracted from the fuel by the steam is concerned, it does make a very important difference, the heat abstracted from the fuel by the steam being the same whether any of it or all of it is afterward condensed, reaching the engine as all steam, partly steam and partly water, or all water. The heat abstracted from the fuel in the last case being that required to evaporate all the feed water pumped in. It is therefore necessary in such experiments to pay particular attention to the amount of surface exposed to the cold air. TEMPERATURE OP CHIMNEY. The temperature of the chimney as shown by thermometer and the temperature of the atmosphere, the difference being one ele- ment of the portion of heat lost, were : ^ ^ ^ ^ & ooooaia: (D |_i • • to W Temperature of chimney gas ... . 700° 580° 580° 510° 420° 700° 580° 490° 480° Temperature of atmospiiere 50° 70° 50° 65° 50° 70° 70° 30° 30° Difference 650° 510° 530° 445° 370° 630° 510° 460° 450° PRIMING. The priming was therefore nothing in all of the boilers experi- mented on. This agrees with all reliable experiments I have ever 38 seen, the water primed as shown by the experiment being less than the instrument could be relied upon to detect. The weight of water pumped in is therefore a measure of the steam formed. ABSOLUTE EFFICIENCY. The absolute efficiency of all the furnaces, as indicated by the experiment, being the heat utihzed in the steam compared with the available heat in the tan, or the proportion that the steam actually evaporated bears to the steam which might be evapo- rated by the same tan in a perfect furnace and boiler, no allow- ance being made for imperfect combustion^ insufficient heating surface or radiation, are as follows : Stevens' 33.6 Wells' (1) M.5 Bracktieyvllle 57.1 Weed 64.7 Wells' (2) 45.8 Wilcox (1) 68.9 Wilcox (2) 75.7 Wells' (3) 61.1 Wells' (4) 57.3 The only furnaces that are fairly comparable are those at the same rate of combustion per square foot of boiler surface. The rates of combustion — that is, the pounds of dry tan burned per square foot per hour, were : 1.61 Wilcox (1) Wells' il) 0.98 Wilcox (2) Brackneyville 0.73 Wells' (3) Weed 0.67 Wells' (4) Wells' (2) 0.64 .0.63 Of these experiments Wells' (1) and Wilcox (1) are at nearly the same rate ; also Brackneyville and Wilcox (2) ; also Weed and Wells' (3) ; Wells' (2) and (4) and Stevens' being out as experi- ments made under exceptional conditions. Comparing the experiments together, then, that have the same rate of combustion, there results : Hoyt. Crockett. Pounds dry tan bnrned per square foot of heating sur- face per liour 1.05 0.98 Absolute efi&ciency 0.689 0.445 Relative efficiency 100. 64. For the next lowest rate of combustion : Hoyt. Thompson. Pounds of dry tan burned per square foot of heating surface per hour 0.79 0.73 Absolute efficiency 0.757 0.571 Belative efficiency 100. 76. For the lowest rate of combustion : Thompson. Crockett. Pounds dry tan burned per square fiot of heating surface per hour 0,67 0.63 Absolute efficiency 0.647 0.611 Relative efficiency 106. 100. 39 Althougli the expeiiments at Brackneyville and Wells' (1) can- not be compared directly together, they are both compared with the same furnace at different rates of combustion, and the result- ing ratios may be compared (that is, 76 and 64), the final ratio being 100 and 118. The final ratios then are (each furnace being at the same rate of combustion) : Hoyt 122 Thompson Ill Crockett 100 These are the actual experimental comparative efficiencies of two Thompson, two Hoyt and two Crockett furnaces, furnace being taken in the actual condition found. The question now arises, " How much of this difference is due to the principle of construction and how much to the superiorities or defects of each particular furmacey The answer to this question may be very accurately inferred from the figures abeady given in the report. The main causes of difference are : 1. Incomplete combustion. 2. Dilution of air either passing through fire or leaking into flues. INCOMPLETE COMBUSTION. The table at the end shows the total heat accounted for in the six cases where the air passing up the chimney was measured, as follows : Wells (1). Brack. We:d. Wilcox (1). Wi'cox(2). Wells (3). 4.01 4.53 4.61 5.30 4.17 2.28 1.91 1.61 2.19 2.09 2.07 2.94 2.40 1.33 1.73 1.40 1.96 Water of combustion 0.45 0.45 0.50 0.45 0.45 0.45 Sum of above four quantities. . . 8.70 8.77 7.97 8.98 9.24 8.65 Calculated thermal e quivalent 9.00 8.90 8.60 9.00 9.00 8.90 Difiference boios heat unac- counted for from all causes. .0.30 —0.13 —0 63 -f0.02 -f-0.24 —0.25 It appears from the above that the combustion was sensibly complete in all except Brackneyville and Weed (the discrepancies between Wilcox (1) and (2) showing the limit of accuracy of experiment). INCOMPLETE COMBUSTION CAUSED BY CONTRACTED FLUE. There is a way in which the contracted opening from the oven into the flue may act injuriously in the Thompson furnace if car- ried to excess, and is positively a cause for the failure of many 40 of the earlier Thompson ovens, and for the incomplete combus tion of the Weed furnace. If the opening from the oven into the combustion chamber is as much contracted that it is the controlling section, that is to say, if it is so small that the principal resistance offered to the flow of the gas from the ash pit door to the chimney top is at this point, then a considerable portion of the combustible gas will escape unburned. The cord of wet tan as fed into the furnace contains : Water '.2,700 pounds. C^B'S 870 pounds. Pixed carbon 600 pounds. •^shes 30 pounds. If completely burned the products of combustion will be at the temperature of the furnace (say 1,800°) and will have the fol- lowing volume : steam 240,000 cubic feet. Gas and steam and aT. 300,000 cubic feet. Carbonic acid and air 600,000 cubic feet. 1,140,000 cubic feet. It appears, then, that there must pass through the outlet of the furnace 1,140,000 cubic feet for every cord of tan burned. At the Weed furnace there was burned in each oven one-eight of a cord per hour, and therefore there must have passed through each outlet 140,000 cubic feet per hour. If the outlet had been the controlling section, it would have passed this volume, or 2,300 feet per minute and no more. The ovens were fed nearly every hour, and therefore the weight of the charge must have been |(4,200)=505 pounds, containing a volume of steam and gas that will be generated soon after its entrance into the furnace, equal to : steam 30,000 cubic feet. Combustible gas ; 10,000 cubic feet. 40,000 cubic feet. being a volume sufficient to fill all outlet from the furnace and completely arrest the inflow of air, during 17 minutes, if the gas and steam were completely driven off in this time. The loss in this case would be the heat equivalent to all the combustible gas, or about 25 per cent. The process of completely drying and coking the tan lasts during the whole time, fi'om one time of feeding until another, but is most rapid during the first ten minutes, and probably nearly all the gas generated during the first ten minutes in the Weed 41 furnace was lost. The actual loss of heat from incomplete com- bustion was about 8 per cent., indicating that one-third of the gas passed away unconsumed in this way. The fact that there was a pressure, or at all events an equili- brium of the gas in the furnace over the atmosphere, just after firing, was shown by the fact that the smoke from the tan in the feed holes returned into the fire room at this time, and kept it so full of smoke as to be almost unendurable. This was not so at Brackneyville or WUcox. In order that the outlet from the Weed oven should be the controlling section it must have an area of less than 3 square feet, for the opening into the ash pit that only passed air at 60° was ^ one square foot. The actual area may be computed from Wells' (4), when the outlet was reduced until it was the controlling section, and must be, in order to be the controlling section, less than 400 square inches. The actual area of the outlet was 256 square inches, being too small to pass the gas and steam as fast as generated, and the air necessary for the combustion. EXPERIMENT ON REDUCTION OF OUTLET. An experiment was made marked Wells' (4), in which the out- let from the flues was reduced until it began to sensibly aflfect the draught. The area of the outlet was reduced to 2^ square feet, and the tan consumed | of a cord per hour, containing (at the temperature of the chimney) : steam 100,000 cubic feet per cord Gas and air 120,000 cubic feet per cord Carbonic acid and air 240,000 cubic feet per cord 460,000 cubic feet per cord being nearly 2,300 cubic feet per minute. The furnace was fed every 16 minutes, and, therefore, the charge, 1-12 of one cord, containing : steam 8,300 cubic feet Combustible gas 3,000 cubic feet 11,300 cubic feet or enough to completely fill all passages for egress from furnace for 4| minutes. If the gas were all driven from the tan during this time all passages for egress would be filled, no air could enter, and all combustible gas must be wasted, and the loss would be, as before, about 25 per cent. If the period of drying of tan extended from time of feeding until the time of feeding again, and the gas and steam were ex pelled uniformly, the loss would be zero. I judge from the appearance of the fire that the time occupied by the gas and steam in perfectly leaving the tan was about 10 minutes, and that therefore the loss was less than 10 per cent. The actual loss from experiment was about 6 per cent. The controlling section was found to be at the ash pit 100 square inches, and the section that commenced to affect the draft at the chimney 360 square inches, from which I infer that in order to perfectly consume the tan in a furnace fed from the front, or with two feed holes, the areas of opening for air must be, per pound of dry tan burned per hour (with a chimney 80 feet high and a temperature of 500°) : Ash pit 0.20 square inches Outlet of furnace. 2.50 square inches Entrance to chimney 1.00 square inches Entrance to flues (when one oven is connected to boiler) 1.50 square inches and that an area of the following area per pound of dry tan per hour will be the controlling section, and will limit the rate of combustion : Ash pit 0.20 square iuches Outlet of furnace 0.90 square inches Entrance to chimney 0.50 square inches Entrance to flues 0.60 square inches In the old Thompson furnace at Wells' there were 4 openings from the oven into the combustion chamber, each said to be 18 inches square — 1,300 square inches. They used to burn 600 pounds of tan per hour with difficulty. This i explains why they had so much trouble to keep steam. They need all the steam coming from 500 pounds of tan per hour, and if they waste all the combustible gas they must burn 1,000 per hour. This would be at the rate of 1 3-10 square inch of outlet for every pound of dry tan, or nearly the limit of thefurnare in good weather under favorable circumstances. If for any reason the maximum per- formance is suspended for a few minutes the tannery must stop and wait for steam. This they often had to do. Probably their whole difficulty would be overcome by enlarging the outlets from the furnace to 2| square feet each. I have no doubt this may be done to advantage in many existing Thompson furnaces. At Brackneyville the area of outlet from furnace was 1^ square inches per pound of dry tan per hour, being too small. The loss by combustible gas here was 5 per cent, of heat utilized. The economy of Weed's furnace would probably be increased 4:3 25 per cent, hj either doubling the area of outlet from the oven or by reducing the consumption. The rapidity of drying and coking the tan in the furnace de- pends upon the surface of the tan exposed to the radiant heat (being equal to the grate surface in a farnace fed from the front, and to the entire surface of the cones in the furnace fed from the top), while the amount of water to be given off depends upon the rate of combustion, and the portion of the time occu- pied in the drying of the tan upon the thickness of the bed on the grate. Thus the water and gas will be given oft' more uni- formly during the whole process of combustion if the fire is carried on the grate 12 inches thick than 8 inches, and if the hight of the cone in a furnace fed from the top is 6 feet than 4^ feet. The hight of the cone being limited by the size of the oven, it follows that for an oven 6 feet in diameter the areas of outlet may be smaller. It is for this reason I Judge that the Hoyt furnace at Wilcox was able to burn at the rate of one pound of dry tan to 1.0 square inch of flue area, and to 6-10 square inch of chimney area, both being less than the limiting areas for a furnace 4^ feet in diameter, or a Crockett furnace, without loss, although it will be noticed that the heat accounted for in the second experiment is more than in the first, indicating better combustion at the slower rate. Also when there are four feed holes there is a greater chance of one cone being freshly fed and giving off steam and gas all the time. If there were cones enough the cross areas of outlet, chimney and flue might be reduced to the limiting areas without loss. I think that suf- ficient air for combustion of the gases would enter the Thomp- son oven in the portion of the rectangular grate left uncovered by the circular bases of the cones, for these cones are spaced further apart in the Thompson furnace io proportion to the hight than in the Hoyt. The portion of the grate left uncovered, or covered very thin, would remain or soon become bare. These openings fulfill the same part as the holes in the " Crockett " fire. The furnace at Binghamton was arranged so that the ovens were all connected in pairs, the furnace at Brackneyville so that one pair was connected and one single, and the furnace at Wil- cox so that each oven was single. The combustion at Wilcox was sensibly perfect, whilq at Binghamton it was very imper- fect. There is no escape from the conclusion that connecting the furnaces together was at least of no benefit. The same may be said of the hot ash pit. 44 It appears from tlie figures given in report that the combus- tion was more perfect at Brackney villa, and that also the sup- ply of air per pound of tan was most : Weed. Brackneyvil'e. Percentafje of total heat in bark lost by imperfect combustion 9.0 2.4 Pounds of air supplied per pound of dry tau 9.1 12. Per cent, of air in excess of that necessary for combustion 50. 75. It would appear from these figures that it was necessary to supply 1| as much air to the Thompson furnace as was necessa- ry for combustion, and only 1 4-10 times as much as was neces- sary for combustion to the Hoyt. I believe this is actually the case, not because of any of Thompson's patents, but because in the Hoyt furnace there are four feed cones, and the air and com- bustible gas have a better opportunity to be thoroughly inter- mingled than in either of the Thompson furnaces when there were only two feed cones ; also because a greater part of the air in the Hoyt furnace is admitted directly into the oven above the fire, and has an opportunity to mix wdth the gas and consume it, while in the Thompson furnace it must first pass through the fire and then consume the gas. It will be very hard to get a suffi- cient supply of air to pass through the fire without being taken up by the red-hot embers. I doubt very much whether it would be possible to have an excess of 75-100 of the air taken up in the oven of the Thompson furnace as built at Bingliamton that is, without some means of supplying fresh air into the combustion chamber. At Brackneyville air was supplied to the combustion chamber through leaks in the badly-fitting door, A few holes in the door of the combustion chamber at Weed's would supply the air necessary. Assuming, then, that there will be required in a Thompson fur- nace with two feed holes 1| as much air as is necessary, or 12 3-10 pounds per pound of dry tan, and that the air supply in the Crockett furnace must be 1 6-10 times as much as in the Hoyt, or 16 pounds of air per pound of dry tan, the maximum absolute officiency of the three furnaces will be when the chim - ney gas is at 500°, and when the wet tan contains 62 per cent, of water : Hoyt 82.6 110.8 ThompBon 79.2 106.2 Crockett 74.6 100.0 In this comparison each furnace has been taken with the air supply actually found by experiment, while from what has been said it appears that the Crockett furnace will only need 13 pounds of air per pound of dry tan. I have not made a comparison on 45 the basis of 13 pounds of air for the Crockett furnace because it was not an experimental determination, and may be open to crit- icism. !N"evertheless, I have no doubt that if each furnace were pro- portioned in the best manner, and the walls tight, there would only be required 13 pounds of air per pound of dry tan, when the relative efficiencies would be : Hoyt 105.4 Thomijson • 101.2 Crockett 100.0 The best and an almost perfect result, has been obtained in a furnace having an open backed single oven, with a cool ash pit. The results of these experiments go to show that two of Thomp- son's claims, namely : the hot ash pit and the reduced outlet from the furnaces are absolutely injurious, and that the third, i. e. , the combination of a pair of ovens, is at most of no value, for a practically perfect result can be obtained without the com- bination in one oven. It has been customary to compare experiments on these fur- naces, by adding the water evaporated in the boilers to the water in the tan, and by dividing the sum for one furnace by the sum for the other, paying no attention to the size of the boilers, the method of firing, the state of repair, or to anything but the water evapo- rated and the tan burned. The results thus obtained give no idea of the relative merits of the two furnaces, but as this method has been persistently adhered to in former reports, such a comparison is made here, with the following results : The average of all of each kind. Thompson. .109 Crockett.... 110 The best furnace of each kind Thompson.. 99 Crockett 100 The poorest Crockett with the best Thompson. .Thompson. .137 Crockett.... 100 The poorest Thompson with the best Crockett. .Thompson. . 97 Crockett.. ..100 It appears that by comparing m this way and selecting ex- amples, any result from a superiority of 37 per cent, to an inferi- ority of 3 per cent, may be obtained for the Thompson, while the relative efficiency of the two furnaces as shown by the experi- ment is : Thompson 106 Crockett 100 The results of these experiments indicate that for a furnace having a chimney 80 feet high, and discharging the gas at a tern- perature of 600°, the atmosphere being 60°, and the tan bemg well leached and contaming 62 per cent, of water, compared with the residue dried at 110° C, as follows : CALORIFIC POWER. One pound of wet tan will, when perfectly consumed, evaporate 2 pounds of water from 212°, or 5 pounds from 212° per pound of dry tan, being about | of the water that would be evaporated by one pound of the dry portion or ordiiiary pine wood. POOREST PERFORMANCE. One-third of the heat may be wasted by careless firing or inferior design of oven, and that there wiU be evaporated under these circumstances 2^ pounds of water for each pound of the dry tan. CROSS SECTION OF FLUES. That in order to insure perfect combustion, the area of egress for the gas from the boiler must exceed that necessary for coal or wood, and riiust be for an oven with two feed holes, or fed from the front at least, for each pound of dry tan burned per hour at the Outlet of oven 2.50 square inches Entrance to flues 1.50 square inches Entrance to chimney l.QO square inches and that the draught must he controlled at the ash pit door. When two ovens are connected to one boiler, or when one oven has four feed holes, the areas of egress per pound of dry tan per hour may be : Entrance to flues 1.00 Entrance to chimney 0.75 LEAST SECTION OF FLUES, ETC. When the fire is forced to the uttermost, the number of inches of sectional area at the various points in the passage of the gas from the ash pit to the chimney top will be : Entrance lo ash pit 0_20 Oxitlet to furnace 0.90 Entrance to flues 0.60 Entrance to chimnej' 0.50 COMBUSTION PER SQUARE FOOT OF GRATE. Under the above circumstances the tan wiU. bum at the rate of lOi pounds of dry tan per square foot of grate per hour at least, and possibly more. It is, however, favorable to economy to have a slow combustion per square foot of grate surface, not exceeding 47 5 pounds per square foot of gi-ate per hour, and probably even slower. HEATING SURFACE. There will be requu*ed m the Crockett furnace when burning 5 pounds of dry tan per square foot of grate surface per hour 1^ feet, and in the Hoyt furnace 1| feet of heating surface for each pound of dry tan burned per hour, being in the last case about the same proportion as would be required for a furnace burning coal or wood to furnish about the same amount of heat. Although the heating surface required for coal or wood is the same as for tan, the cross section of the flues is required to be about double, and the grate surface about four times as much, so that if the same boilers which originall}^ could just furnish steam with wood or coal were attached to a furnace burning tan the chimney would have to be much higher. AIR SUPPLY. The least air used in any of the experiments when the combus- tion was complete was 10 pounds per pound of dry tan, or an excess over that actually necessary of 40 per cent., about the same as is found in a coal fire. RESULTS OBTAINED. , That when these proportions are observed the combustion was found to be perfect in the Hoyt and Crockett oven, and would un- doubtedly be perfect in the Thompson if the ash pit was cleared out and the area of outlet at the back of the furnace enlarged, and that while it may be the results of the patented furnace may become with skiUful management and design equal to the unpatented, it appears that the unpatented furnace is practically perfect, and that therefore the patented attachments have no value at all. THERMAL EQUIVALENT OF BARK. The numbers assumed for the thermal equivalent of bark dried at 110° C. (unleached 8^, leached 9.00 pounds of water from 212°) are probably comparatively com ct. Nevertheless, from the fact that in the two experiments at Wilcox the heat accounted for overruns these numbers, while at WeUs' (1) and (2) it reaches it, there being no [margin for incomplete combustion and radiation. I am of the opinion that the thermal equivalent of hemlock bark, probably from the extra amount of resin it contains, is more than these numbers, and is at least 9 pounds of water from 212° for the unleached bark dried at 110° C. and 9^ pounds for the leached bark. 4:8 The details of the drying of the tan, and also of a very elegant experiment for drawing and analyzing the chimney gas, devised and executed by my associate, Mr. J. K. Rees, were under his especial charge, and are properly the subject of an independent report, Yery respectfully, THERON SKEEL. APPENDIX. Dimensions of Ovens and Boilers. Name of owner Kind of oven Kind of boiler Material of chimney Hight of chimney above grate, ft. Grate surface, sq. ft Heating surface, sq. ft Cross area of flues or tubes, sq, ft. Cross area of stack, sq. ft PKOPOBTIONS. Grate surface to heating surface. Grate surface to cross area tubes. Great Bend, N. Y. Webb's Mills N. Y. Br'kneyville, ]N. Y. Binghamton N. Y. Wilcox, Pa. Stevens. Wells. Weed. Schultz. Crockett. Crockett. Thompson. Thompson. Hoyt. Flue. Flue. Flue. Tubular. Flue. Iron. Iron . Iron. Brick. Brick. 74 HO 80 94 109 60 78 162 243 192 400 830 480 2,000 950 2.30 5.54 3.14 8.33 6.4 5.40 5.24 4.90 9 16 for 4 ovens 1 : 6.66 1 : 16.4 1 : 2.9 1 : 8.2 1 : 4.75 24 : 1 14 : 1 51 : 1 29 : 1 30 : 1 n : 1 33 : 1 33 : 1 27 :1 24 : 1 Statement of 3Ieans nnd Totals of Observations and 3£easiirements. Date of E.xperiment | Sept. Sept. Oct. Name of owner of furnace. Number of experiment ] Duration of experiment, hours' Pressure of steam TOTALS. Poundsof wet tan consumed. Pounds of a.shes and refuse . . Pounds of combustible Pounds of feed water TEMPER.\TUBE. Furnace (maximum) . . Furnace (average) Atmosphere Chimne.v Feed water Ash pit Per cent, water in wet spent tan dried at 110° C Percent, ashes and refuse — Per cent, water in gr'n ground bark dried at 110° C ■WEIGHTS. Weight cord unleached bark Weight cord leached wet tan Weight cord leached dry tan. Weight cord packed wet tan. 36,138 70'633 2,000° 1,900= 65° 510° 195° 1,500° 4,270 1,917.2 Wells II. 12 29 17.282 isiseo 1,900° ' ' 50° 420° 140° 4.225 1,571.7 5,490 Wilcox I. 62,123 98,6i8 2,000° 2,000° 70° 700° 41° 70° Wilcox II. 24 75 46,612 81^256 2,000° 2,0 0° 70° 58'>° 41° (fine ( ( 18.1 j ( fine ) I ( crs ) ( '2418 \ ( 2284 S 4.076 4,076 1,581.9 1,581.9 4,275 1,645.9 4,260 1,606.0 50 Mesiii of Obsei-vulioii!* on Appariitus tor Detecting Wiiter Entrained in Steam. Wells. Brack- Weed. Wells. Wil- (l.J ney. (i.) cox. Number of hoiir.s apparatus was in use 5 5 6 6 11 Mean temperature of injection 49.4 57.25 56.29 48.8 40.9 Mean temperature of discharge 99.1 98 5 104,61 73.73 83.44 Mean temperature of worm 111 102 118.3 74.9 92.80 Pounds water from worm per hour 99 91.7 94.4 49.8 81.18 19.(0; 21.75 18.3 19.625 20.125 Pressure of steam above atmosphere 55 53 71 26. 69 Calculated Kesults From Experiments. Name of furnace [Stevens. | Wells. Brack. Weed. Wells. Wilcox. Wilcox. Number of e.xperiment. Percentage of water m tan Percentage of solid matter in tan Weight of cord of wet tan Weight of dry portion of do Weight of insoluble portion do. . . . Weight of portion lost by boiling.. HOURLY QUANTITIES. Pounds of wet tan burned. Pounds of dry tan burned. Pounds of wet tan per sq. ft. grate. Pounds of dry tan ner sq. ft. grate Pounds of wet tan persq. ft. heat- ing surface Pounds of dry tan per sq. ft. heat^ ing surface Pounds of wet tan per sq. ft. cross section of Hues Pounds of dry tan per sq. ft. cross section of tlues 61.5 38.5 4.442 1,710 1,626 84 Pounds water evaporated Pounds water entrained with steam Per pound wet tan from feed. Per pound dry tan from feed. Per pound wet tan from 212= Per pound dry tan from 212= Pounds water evaporated from 212' per sq. ft. heating surface Per cent, of carbonic acid in dry gas by volume Per cent, of oxygen in dry gas by volume Pounds air per pound dry tancaJ- culatsd from velocity of smoke. DISTRIBUTION OF HEAT OF ONE POUND OF DRY TAN IN POUNDS OF ■WATER EVAP0R.4.TED FROM 212°. ! Gas pas.sing up chimney heated from temperature of atmosphere to temperature of chimney Water in tan evaporated from 68° and superheated to temperature of chimney Water evaporated in boiler from 212° Water of combustion, estimated.. Sum of above four (juantities Thermal equivalent of tan (cal)... Difference, being loss from all causes, incomplete combustion, radiation, etc Available heat per pound of dry tan Absolute efficiency of furnace and boiler 27.9 10.7 4.19 1.61 258 1,397 0.833 2.161 0 893 2.319 63.4 I 09.0 36.6 41.0 4.294 I 4,112 1,571.6 1 1,648.9 1,478 1,536 93.6 112.9 2,235 818 28.7 10.5 2,327 33 1.041 2.809 1.117 3.025 3.36 7.5 14.9 22 3.03 0 45 8.70 9.0J 030 6.72 45.0 1.81 0.73 270 110 1,203 95 1.390 3.329 1.680 4.098 13.3 18 55.1 44.9 4,270 1,917.2 1,509 408.2 3,011 1,352 12.4 5.6 1.50 0.67 360 160 5,836 1.938 4.319 1.988 4,529 11.1 10.6 10):,' 4.01 0.45 II. 62.8 37.2 4.225 1,571.7 1,421 147.7 1,440 536 18.4 6.8 1.72 0.64 4.53 7.97 8.60 1.074 2.887 1.192 3.204 6.99 64.7 61.2 38.8 4,076 1,581.9 1,484 97.9 13,4 5.2 2. 72 1 05 404 157 4,084 >s.h.24° 1.523 3 925 1.790 4.613 II. 61.2 38.8 4,076 1,531.9 1,484 97.9 1,942 754 10.1 3.9 2.04 0.79 303 119 3.385 i.h.24° 1.750 4.510 2.058 5.304 4.61 0.45 8.98 9.00 6.81 67.8 5.30 0.45 9.24 9.00 6.91 76.7 Wells. Wells. III. I IV. 61.5 1 62.3 38 5 37.7 4,275 I 4,260 1,645.9 I 1,606.0 1,419 546 18.2 6.1 1.71 0.66 2,048 1.443 3.747 1.605 4.168 2.73 8.2 14.7 16 4.17 0.45 8.65 8.90 6.83 61.1 *Super-heated, 24°. REMARKS ON EXPERIMENTS. (I'rom jYote Sook . ; Made an experiment on Crockett furnace Sept 21 and 22. Used bark that had been pitched out from leaches 24 hours before, and had been draining on ground during that time. Tan was meas- ured in box and each box weighed. Furnaces were fired by M. A. Stevens in the usual manner, i. e., furnace was fired every 10 minutes nearly, tan bemg thrown in through both doors and whole surface of grate covered 6 inches or 8 inches thick. Con- siderable white smoke issued fr-om the stack all the time, but most for a few minutes after firing. Temperature of crown of frirnace near fire bridge (perhaps over half of furnace) was, when the door was opened, a dull red ; soon became black after firing. A part of unburned tan dropped through holes in gi-ate mto ash pit at a bright red heat and slowly consumed there without blaze. The temperature of ash pit was found by thermometer held close up under grate bars, near back end, 480°-545°. The grates were of iron and had been in use 8 years ; were badly warped, and cracks were covered over with fragments of iron ; it was through these cracks that tan fell into ash pit. There must have been consider- able heat lost by radiation from brick work and iron uptake. Chimney was part brick and part sheet iron. Sparks could be seen in large quantities through hole cut for thermometer, and once were seen from top of stack. A great many sparks seemed to leave the furnace over bridge wall, and on opening back connection doors cinders were found which commenced to consume as soon as air was admitted. * * * Feed water was heated by passing through pipe surrounded by steam; was found to be nearly tight. Temperature of feed 150° well water 54°. Tally of ban-els of water and boxes of tan were kept by two persons independently. Water was started at three cocks and brought to this point at end. Sample of tan was taken from various parts of heap at 8 p. m. Zinc was not melted in chimney or ash pit. Copper was not melted iii furnace. Silver was melted in furnace. There were many crevasses in brick work around boiler wliicli emitted smoke during some portion of time, and wliicli in back connection were surrounded bj deposit of " coal tar." Dimensions of box in which tan was measured : 3 feet 6j incliesX^ feet 3 inchesX 2 feet 0^ inch ; capacity, 16.2 cubic feet. * * * -K- -x- -x- * * * Made experiment on Crockett furnace at Webb's Mills, recently erected, and owned by Mr. Wells. Cone grates in good condition. * * * Water measured in barrels, tan measured in boxes. Tan had been draining in leach 24 hours before and was pitched during exjDeriment ; was wdieeled 100 feet in barrows, and then dumped 10 feet to fire room floor. * * * During first part of experiment damper one-half open and furnace cool ; ash pit door 8 inches open. During last haK fires thicker, i. e., 6 inches over crest and 15 inches over hollow of bars ; damper open ; ash pit doors 2^ inches open ; furnace much hotter ; steam variable, from 45 to 65 pounds. Stack of sheet iron. Feed water passed through heater said and believed to be tight. Pumps worked all time. Water supplied to barrels by centrifugal pump. Sides of furnace and boiler enclosed by walls of house. Tan apparently wetter than at Great Bend and coarser. Boilers apparently good. Gases drawn every hour. - * Engine running all night, blowing off occasionally. Water carried during experiment at first gauge, but commenced and ended at second gauge. Arches were noticed toward the end to be bright red before firing. Seams below the surface remaining hot when arches were black after firing. Weight of a barrel of water, 315 pounds. Dimensions of box for measur- ing tan, 3 feet 2 mchesX2 feet 3 j inchesXl foot 11 inches ; capacity, 13.78 cubic feet. * * -X- * * * -X- ^5- Made experiment on furnace at Binghamton, Sept. 29, 9 a. m. till 9 p. m. Ovens were fed with tan that had drained 36 hours, and was pitched continuously during experiment. Tan weighed 53 and measured as in other experiments. Water measured in casks. The weight of water at 56^ necessary to fill cask, 358 pounds. Temperature of water when measured during experiment, 205°. Had counter on pump. Pump delivered a varying volume of water, depending upon the depth of water over the suction pipe. Priming determined in the usual way. Air clear, wind south and fresh. No smoke fi'om the stack at any time. Never melted copper in combustion chamber. Silver melted easily ; silver melted in ash pit when held close to surface of embers. Ash pits were not cleaned during the experiment except No. 2 oven. Back connection doors showed dull red in the dark. Dimensions of box for measuring tan, 2 feet 8 inchesX2 feet 10 inchesX2 feet 4| inches ; capacity, 17.8 cubic feet. Dampers wide open all the time. No smoke from chimney. Time of smoke reaching chimney top from combustion chamber, No. 1 and 2 oven, 10 seconds. Made experiment on Thompson furnace, Sept. 25-26, from 8 p. m. till 8 a. m. Tan used measured in a box and weighed on scales. About one-third of the tan had been over the oven some hours (at least twelve) before experiment commenced; balance shoveled from the leach about eight hours before. These two kinds of tan were mixed by shoveHng from one end of the fire room to the other before experiment commenced. Whenever weight of box of tan in log is marked (*) signifies that a boxfull had been taken from top of oven ; others were taken from heap not on top of oven. Ovens were kept buried about three feet deep in wet tan during whole experiment. Ash pits were not cleaned out, as owners said they could not keep up steam without cinders in them. Boilers connected to brick pier supporting chimney through sheet iron front connection. Wet tan laying against this connection took fire and burned with flame during whole experi- ment. Made sure that the blow-oif valve was not leaking by filling it with tan. Silver was melted in one flue leading from one pair of ovens but not fi'om other. Fires on being examined seemed to be equally hot. Furnace was fired every 2| hours, nearly, through holes furthest from the door, and every 11 hours 54 tlirough holes nearest to door. All holes iii all furnaces in same position were fired at once, i. e., all holes nearest to boiler every 2.^ hours, and all holes furthest fi-om boiler every li hours. Fur- nace doors had no holes in them and were kept tightly closed and luted with fire clay. Ash pit doors were of sheet iron, about 2 feet square, and were kept so as to expose an opening for the passage of air of about 40 square inches to each oven. Glass water gauge in chimney showed one-half inch ; did not fall when large door to back uptake, 2 square feet, was opened. Tempera- ture of stack, 580°. Seems probable that almost all combustion took place on surface of cone. Amount consumed in ash pit small. Temperature of ash pit 600-. Water was measured in barrels and passed into tank by three men with pails. Tally was kept by two men mdependently. Chimney gases were drawn every hour till 4 a. m. Experiment on velocity of air in stack Avas made with coal smoke. Time required to reach chimney top from combustion chamber was : 10, 11, 10, 11, 12, Hi, 9, 9, 9, 9, 9 seconds ; mean, 10.01 seconds. Weight of a barrel of water, 390 pounds. Flues were swept before experiment commenced. Boilers were fed by injector ; no heater ; drip water fi-om injector returned to tank. Doors around the furnace and cracks were all luted with blue clay and ashes before experiment. Holes above the furnace were kept covered with tan, and covers not used. Weather ramy durmg the night and damp in morning. Air, 50° ; boiler room, 70°. Dimensions of box for measuring tan : 2 feet 1^- inchesX2 feet 8^ mchesX2 feet 7 j inches ; capacity, 14.69. THEEON SKEEL. 58 THOMPSON FURNACES. The Moses TlifiiiiLSOii Patciil for Wet Tan Burning FiiriiHce^. ( Extracts from Patent, slioiving Claim and manner of icorl'ing Furnaces.) SUBMITTED BY J. S. SCHULTZ, J. B. HOYT AKD OTHERS. Fig. 1 is a horizontal section of a furnace constructed according to my invention. Fig. 2 is a vertical section of the same in the line x 7j of Fig. 1. The main object of my invention is to effect the more economi- cal use for fuel of tan bark, bagasse, or other trashy matters in a wet state, or very green or wet wood. It is also applicable to the burning of fuel of that or other de- scriptions in a di-y state ; but when the fuel is dry it is much less useful, and I do not claim its ap])lication thereto. The nature of my invention consists in the employment, in the manner hereinafter described, of a series of fire chambers ar- ranged side by side or in any convenient way, to admit of the whole series communicating with the same heating flue, which said fire chambers are furnished with dampers by which their re- spective communications with the flue and the ash pit may be closed or opened at pleasure. This arrangement is for the purpose of enabling the process of heating the fuel to an intense degree in a nearly air-tight chamber, and then admitting a free supply of air to promote its rapid com- bWibilj to-litcoigrckietkl ^MoiiV inte^^ to the oiDerations wliich the heat ^ener^ted.ia ii3iteii(ie(i^t«.felfect. To enabJe. HH^fS sM^VlW'tl-ietirl to fiiake and use my inven- tion, I will proceed to describe its construction and operation. The furnace shown in the drawings has three fire chambers, A, A.', k". Three is the number shown, as I consider that number in most cases to be the best adapted for practical operation. The fire chambers are of square but may be of other form with gi^ate bottoms, B, B B ' and arched tops. They are separated by walls of non-conducting material, and hned throughout with fire brick.. Each is provided with a door, C, in front for the purpose of light- ing and tending the fire, mtli an opening, D, at the top, for the purpose of supplymg the fuel when it consists of tan bark, saw dust, or other material of a similar nature, and with an opening, E, at the back, which leads to the flue, F, the opening, E, being provided with a damper, K. Each fire chamber has a separate ash pit, G, below it, which is furnished with a door, H, to regulate the admission of air. The flue, F, extends across the back of all three fire chambers, and the chimney may be at one end or may be placed in the rear, with a flue, I, leading to it fi'om the flue, F. If the furnace is used for generatmg steam, the best place for the boiler will be in the flue I, which will be made of proper size to receive and nearly surroimd it. If used for other purposes, any arrangement may be made that may be considered best, but the thing to be heated ought to be so high as not to require the products of combustion to descend on their passage to it. The mode of conducting the operations of the furnace is as foUows : Fires being lighted in all the fire chambers, two of the three have the doors, H, H, of their ash pits closed, and the dampers, K, K, so nearly closed as only to allow a sufficient escape of the gases generated by the slow combustion which then goes on to prevent explosion. The other fire chamber in the meantime has the damper K open, and the door of the ash pit opened far enough to admit any quantity of air that may be requisite to promote such a degree of combustion in the chamber as may be necessary to generate the amount of heat required. The air should be cbawn in (except when excluded) by natural draft, and if a high stack be used, there should be a damper in it to check the draft. When the fluel in the open chamber is reduced to a desii-able degree that chamber is closed and recharged, and another opened 61 and supplied with air until the fuel within is reduced, when it is closed, recharged, and another opened, each in its turn being opened and freely supplied with air to generate and supply the requisite amount of heat, while the others are closed and succes- sively supplied with fresh wet fuel to heat and|decompose the same to such a degree as is desu-able before allowmg rapid com- bustion and escape of the heat to take place. Each fire chamber should be supplied successively with fuel at proper intervals by any convenient means, either through the hole, D, or through the door, C, in front, just before closing the fire chamber. The principal advantage of a furnace and process of this de- scription consists in heating and decomposing the fuel without any further loss of heat than is absorbed by the poor conducting material of which the furnace is constructed, to such a degTee as will, when a proper supply of air is admitted, cause the most per- fect c^combustion of the gases and smoke to be effected. This could not be effected in a single fire chamber without interruption to the proper supply of heat, but when two or more fire chambers are employed no interruption takes place, as one furnace is always in full operation. Another advantage consists in always holding a certain quantity of heat in reserve in the closed chambers, which may be immediately brought into action by opening one or more of the chambers. A similar but inferior result might be produced by having several separate grates and ash pits to the same fire chamber, each grate charged successively, and its ash pit for a time closed, immediately after fresh charging, to exclude the air. I have described this in my caveat upon which this application is based, but do not use it because of its inferiority in practice, although it involves my principle. After ample experiments, I have discovered that any results which can be produced by the use of dry fuel are entirely inferior to mine in proportion to the quantity used, and that results like mine can only be attained by the use of wet fuel, similar to what I have herein mentioned, fed into an intensely heated chamber. Under such circumstances, the water in the fuel, in the presence of the carbonaceous substances in the furnace, will be decom- posed, giving its oxygen to the carbonaceous matter, dispensing with a draft and its cooHng and wasteful influences, and rendering the combustion so perfect that no smoke is visible. I do not claim the within-described arrangement of a series of fire chambers to communicate with one common flue, irrespective of the i^urpose for which, and the manner in whicli, I employ the said arrangement. But what I do claim as my invention, and desire to secure by letters patent, is : The combustion, for the purposes of a high degree of heat, of bagasse, refuse tan, saw dust, and other refuse substances, or very wet and green wood, by the employment of a series of fire cham- bers, arranged in any manner substantially as described, to com- municate with one flue, when any number of the said chambers are nearly closed to the flue and to the admission of air, when first charged as described, while the remaining chamber or cham- bers is in free communication with the flue, and has a free supply of an- admitted, and each chamber in its turn is nearly closed, and then opened, and has air admitted, whereby the heat required is furnished by the combustion of the fuel in one or more chambers, while the fuel in the other chamber or chambers is being heated and decomposed to a desirable degree, as herem set fortlf, no artificial blast being used. Note.— The drawings of the real Thompson furnace, as seen on page 58, and as described on the three following pages, will suffi- ciently indicate the original idea of the patentee. But the claim has been construed by the Court to cover the stracture on page 55. For the purposes of this examination the legally construed furnace has been assumed to be the true Thompson furnace. There are not over three or four real Thompson furnaces— as indi- cated by the original drawings and description— in existence, and they give very inferior results. J. S. SCHULTZ. Date Due j