%^^i\'!'Xii,ui, \ohut g^ttvjj ®ftm!Sit0tt ^ mn u 1903 Cornell University Library 3 1924 031 261 187 olin.anx The original of tliis bool< is in tine Cornell University Library. There are no known copyright restrictions in the United States on the use of the text. http://www.archive.org/details/cu31 924031 261 1 87 THE PRACTICAL ASSAYER. LONDON : PRINTED BY J. OGDEN AND CO., 172, ST. JOHN STREET. THE Practical Assayer CONTAINING EASY METHODS FOR THE ASSAY OF THE PRINCIPAL METALS AND ALLOYS, Principally designed for Explorers and those interested in Mines By OLIVER NORTH. •WITH ILLUSTRATIONS AND TABLES. EonUon : CHATTO AND WINDUS, PUBLISHERS. 1874. PREFACE. My object in writing this book has been tor provide a want I long felt myself — that is, a concise and clear account of the best and quickest way of assaying the "principal metals. I think most works on this subject mix up the province of the analytical chemist too much with that of the assayer, whereas the two are totally distinct. Analytical chemistry presupposes, as a primary condition, that the operator should be a chemist ; whereas assaying is a mere me- chanical art, depending almost entirely on mani- pulation ; so that the very first chemist of the day might easily be far inferior to a good assayer in estimating the exact value of an ore. Indeed, some of the very best and quickest assayers I ever knew have been Chileno and Mexican youths, who could hardly .write their own names ; and yet their manipulation and knowledge of mixtures, from constant practice, was perfect. Perhaps the very finest manipu- PREFACE. lators and quickest operators in the world are the natives employed in the Indian Mint. I have consequently left out all hard words and formulas, and also some better processes than those given, as I have wished only to recom- mend those methods which are at once easy of execution, useful. to the explorer, and do not necessitate the use of expensive apparatus. I have added the estimations of guano and nitrate of soda, as these substances are now playing such an important part in commerce. In an Appendix I give a description of the Guayacan method of smelting copper, a method which has been the subject of much contention. I recommend all my readers to get Fre- senius's " Handbook of Quantitative Analysis," as well as Church's invaluable " Laboratory Guide" To this latter gentleman my thanks are due for much valuable information in regard to the assay of guano, and also to the Editor of the Mining yournal, for permission to reprint the Smelting articles. London, March i6, 1874. CONTENTS. PAGE. Assay of Copper i „ Silver 46 „ Gold 96 „ Tin 106 „ Lead 117 „ Iron 123 „ Zinc 128 „ Mercury 134 „ Manganese .141 „ Bismuth 148 „ Nickel and Cobalt 155 „ Sulphur 175 „ Arsenic 177 „ Nitrate of Soda 178 „ Guano 181 Appendix^Copper Smelting in Chile . .193 Tables for Determining the Standard of Silver Alloy 213 Assay of Gold or Silver 240 THE PRACTICAL ASSAYER. ASS A Y OF COPPER. In the following pages all description of the assays of copper by the dry way has been omitted, for the following reasons. They are rough and uncertain, inaccurate in their results, and never give the true result even by the most careful manipulation. The roasting pro- cess is an extremely tedious one, and even then desulphurization is rarely complete : if too much flux is employed, portions of the^ copper are retained in the slag ; if too little is used, an impure copper is produced. The assay requires a very high temperature, often unprocura,ble in some out-of-the-way places ; and, moreover, in poor classes of ore the B THE PRACTICAL ASS AVER. results are totally at fault. Both silver and gold are liable to get collected in the copper product, both of which must be eliminated by a separate process. The dry method, no doubt, is exceedingly advantageous to buyers and owners of smelting works, as, although .ores are purchased on a different scale from those assayed by the wet process, yet there is no room for doubt that 'the balance is always most decidedly on the side of the buyer. I shall, therefore, proceed at once to the description of the " precipitation process," as practised almost universally in Chile. The Chileno assayers have brought this process to a really surprising degree of accuracy, and for cleanness, quickness, and cofrectness, it leaves nothing to be desired. This method is pursued In the large laboratory of Guayacan works in Chile, and I am under great obligations to Mr. Cosgrove, the assayer at that establishment, for much of the matter contained in the following descriptions. ASSA Y OF COPPER. APPARATUS, &e., REQUIRED. Some flasks, similar to that marked No. i, for boiling the acid solution. Some precipita- ting flasks, similar to that marked No. 2. No. I. — Best shape of boiling flask, of Bohemian glass, 8 or lo oz. capacity. The sharp shoulders prevent spurtings. Some iron-wire, of the thickness of a goose- quill. Porcelain capsules, with handles and No. 2. — Precipitating flask of best Bohemian glass, about I pint. Capa,city covers. No. 3. A few glass rods, and some THE PRACTICAL ASS AVER. No. 3. — Porcelain capsule for washing the precipitated copper. Capacity I pint. large porcelain evaporating dishes, about twelve inches diameter. METHOD OF ASSAY. We will suppose the operator has received five samples to be assayed : he will proceed as follows. Mark the packets in order, on the top corner, thus, i, 2, 3, 4, 5, before opening them. Take five boiling flasks, well cleaned, and mark them with corresponding numbers, with pen and ink. Turn up your balance, to see if it is in order, and then weigh out 100 grains from each packet, and place them in the several flasks. [N.B. — If the ore is rich, say over 40 per cent., 50 grains is sufficient.] Fold up the packets again, and shut down the balance. If the ore contains sulphur such as copper pyrites, &c., pour in about three teaspoonfuls ASSAV OJ^ COPPER. of pure nitric acid, and set the flask to stand for a few minutes till the violent ebullition ceases, when it may be placed at a very gentle heat, just sufficient to keep it at the boiling point. If we were sure that the ore contains no sulphur whatever, it would be unnecessary to use so much nitric acid ; but it is always best to use a little, even in ores supposed to be free from sulphur. Proceed in like manner with all the flasks. In about a quarter of an hour or more, according to the hardness of the ore and the amount of sulphur it contains, it will commence to be " attacked," that is to say, the sulphur will be observed floating on the top in a black globule. Heat may be now cautiously applied, when the globule gradually " cleans " itself and becomes of a bright yellow. If very unattackable, it may be necessary to add a few more drops' of nitric acid, in order to perfectly clean the sulphur, or, in other words, to render it quite yellow. The contents must now be dried off to a paste, and about two or three teaspoonfuls of pure THE PRACTICAL ASS AVER. muriatic acid added. The solution may now be dried off gradually and evaporated to dry- ness. The best way to accomplish this is to seize the neck of the flask with the tongs, and work it with a circular movement on the sand-bath, so as to get the pasty mass as it were plastered around the sides of the flask : by this means the nitric acid is more effec- tually driven off than if the contents were left to stand upright in one position. A very good plan, when the contents are dried, is to bury the flasks completely in the sand-bath, placing them in an inclined position, to prevent spurting, and heaping up the hot sand over them up to the muzzle. Seize the flask with the tongs, introduce a small glass tube, and gently blow off anynitrou s fumes that may remain : the very gentlest breath is sufficient to effect this, as a sudden puff might blow out particles of the copper contents. When the flask is cool, add another two teapoonfuls of muriatic acid, and evaporate to a thin paste ; then add a little boiling water, and allow to ASSA Y OF COPPER. settle in an inclined position. Should any portions of the ore stick to the side of the flask, the boiling water will remove it; if not, a few minutes boiling on the sand-bath will effect it. The same process having been gone through with all the flasks, the operator now places on a table, close by the sand-bath, five of the flasks for precipitating (No. 2), and places in each a filtering glass about three inches dianieter. Moisten the filters first with boiling water, and then filter the solutions. The best way is to pour in about half at first ; wash down the filter with a few drops of boiling water after it has nearly passed through, and then pour in the other half, taking care to leave as much of the residue behind, as possible. Wash this residue once or twice with hot water, and add to the con^ tents of the filter, and allow the whole to filter through. Then work your filter down from the top with a circular motion of your wash-bottle filled with boiling water. To make sure you have left no copper behind in THE PRACTICAL ASS AVER. the residue in the boiling flask, add to it a few drops of nitric acid, and then a drop or two of ammonia ; if copper is present, a blue colour will appear. Take the filtering papers out and place them on one side, corresponding to the numbers on the flasks, in a warm place near the edge of the sand-bath, to dry. The copper must now be precipitated as follows. The five numbered flasks are placed on the sand-bath to warm gradually, and three or four pieces of iron-wire, about four inches long, are cut off by a pair of sharp pliers. Care must be taken that the ends of these wires are smooth and not jagged, or they might hold minute pieces of copper. Wrap them up in a piece of paper three or four folds thick, doubling the ends over so as to form a small packet. Five packets must be prepared in this way. Place these small packets on the edge of the sand-bath, or any other hot place, until you judge they are somewhere about the heat of boiling water. The object of the paper is, of course, to prevent the wire from ASSA Y OF COPPER. becoming blackened. The solution in the precipitating flasks may now be heated to just the boiling point : take them off the sand-bath and place them on the table. Now take one of the packets of wire, break off one end of the paper envelope, so as to expose the ends of the wire, and, holding No. i flask in an inclined position, slide the wire into the solution, taking care not to let the wire fall heavily in, or it might break the flask. Do the same with all the others. The flasks must now be left to stand for some little time. When the wires are thickly coated with copper, the flasks may be gently shaken, which will detach the copper and expose the wire afresh to the action of the acidulated solution. When the solution is nearly colourless it is better to add about three or four drops of muriatic acid, and give it a boil up for a few seconds only on the sand-bath, to extract the last particles of copper. It may be known when all the copper is precipitated by immersing a piece of bright iron-wire in the solution occa- I o THE PR A CTICAL A SSA YER. sionally near the end of the operation. Directly the copper is precipitated the flasks must be removed from the sand-bath and placed on a table in order, with five capsules numbered accordingly. A large kettle of boil- ing distilled water is placed on the operator's right hand, who proceeds as follows. Take flask No. i, and pour off into the capsule as much of the supernatant liquor as possible, leaving the wire and copper behind. If this is carefully done, this first part may be thrown away. Now pour some boiling water (not too much) into the precipitating flask, allow to settle, and pour off" again : this also, if carefully done, may be rejected ; but, if particles of copper come over, must be retained. More water is added to the flask, and the whole contents of it transferred to the capsule, taking care to leave no specks of copper behind. The flask may be put aside, and the same process be repeated with the other four. The iron-wire must be now cleaned off with the tips of the forefinger and thumb, ASSA Y OF COPPER. and thrown away. It only remains to wash the copper. Opposite each of the five capsules place one of the large evaporating dishes, with a glass rod. Half fill the capsules, one after the other, with boiling water ; stir up with the glass rod, allow to settle, and pour off into the evaporating dishes. The test of good pouring is to leave as much copper as possible in the capsule, and to pour over as little as possible into the large dish. After three or four washings,, add a few drops of muriatic acid to the water, and allow to stand for three minutes. This is to remove any iron that may be present. Pour off, and in the next washing put two" drops of muriatic acid, and drop in a drop of a weak solution of ferro- cyanide of potassium. If iron is present, a blue colour is produced ; but if, on the other hand, a faint pink colour "is produced, it is a sign that too much acid has been used, and a small portion of copper dissolved. This latter error should never occur, and, when it does, a small allowance only must be made 12 THE PRACTICAL ASS AVER. for it, as it is very trifling. If iron is present, the washing must be continued till it is eliminated. After the last addition of acid, three washings are generally given to render the copper perfectly clean. The copper in the evaporating dishes is now to be washed once or twice, and added at once to that in the capsule. The whole is now drained off as dry as possible, and nothing remains but to dry and weigh it. The drying is accomplished thus : When the copper in the capsule is drained of its water, it will, of course, have collected at the edge in the bottom, in a way incon- venient for drying : by holding the capsule, however, with the spout away from you, and inclined to the ground slightly, and giving the bottom, linder the collected copper, a smart tap with the fingers of the right hand, the copper will jump, or rather slide, on to the middle of the capsule, spread out in a thin layer. A little practice with wet sand will soon enable anyone to accomplish this. All draughts must be now excluded, and the capsule ASSAY OF COPPER. 13 placed on the sand-bath at a gentle ■he.sX. Five minutes will generally suffice to dry the assay. This may be known by gently pressing the top of the copper with the point of a knife ; if not dry, it yields gradually to the pressure ; but if dry, it comes off in scales. The covers are now placed on each, and they are taken to the balance-room, and weighed as quickly as possible, by taking out one of the copper pans of the balance, and brushing the contents of each capsule into it with a fine camel's-hair brush. The difference in weight gives the per- centage. The whole operation generally takes about one hour and a half; but a practised assayer can perform it in a quarter of an hour less time. It is not advisable for one assayer to attend to more than five washings at one time, and, where many assays are taken, the assistant is employed during this time in attack- ing and filtering the others. It is a very good plan, where many assays are taken, to weigh out the samples overnight, and leave them in a slightly warm place till the morning, when they 14 THE PRACTICAL ASS AVER. will be found to be ready for filtering. At the large laboratory of Guayacan as many as twenty or more of these assays are taken daily, with only one assistant, besides thirty or forty cyanide assays. The results by this method are most exceedingly correct, when performed by a good operator. In an assay of a valuable cargo of Chile ore, three assays are sometimes taken as a check, and they generally come out within half a tenth per cent, of each other when done by the same as'sayer. A tyro will inva- riably get low results, the loss occurring princi- pally in the washing. OBSERVATIONS ON THE ABOVE METHOD. Although this method is most extremely exact, still considerable practice is necessary, and the following observations, for many of which I am indebted to Senor Domeyko, of the University of Chile, are impressed upon the reader. In attacking the ore always use muriatic ASSAY OF COPPER. 15 acid, and it is best always to use nitric acid in case there is some sulphur in the ore. When sulphuric acid is used, much white residue is formed, which sticks to the side of the flask, and the latter frequently breaks. To avoid this accident, and to complete the dis- solution of the ore, let the assay get cold, and then add water gradually until all the white residue is dissolved. Generally speaking, it is necessary to attack till the residue is white ; but sometimes the residue is black silicate or graphite. When this is the case, the assay may be considered as finished when a fresh dose of acid produces no effect, or we may test it by the blowpipe or cyanide. The operation of evaporating to dryness being troublesome, and liable to loss of oxide of copper in case the residue is heated too much towards the end of the operation, it may be omitted sometimes, provided that the fil- tered liquor passes off perfectly clear, and with excess of acid. Complete evaporation should, however, always be had recourse to if gela- 1 6 THE PRACTICAL ASSAYER. tinous silex appears during the boiling with acids : this substance sticks to the flask, and frequently causes spurtings and projections. In case we suspect that some silex has been precipitated with the copper, we dissolve some of the dried and weighed copper in acid, to see if any residue remains. It is, however, far better always to evaporate to dryness, both to make sure of getting rid of all traces of nitric acid, and to completely dry the silex and render it quite insoluble. Never attack a sulphurous ore too quickly at first : if you do so, the sulphur takes up some portion of the cupreous matter, envelopes it, and renders its extraction extremely difficult. It is better to let it digest at least twenty minutes, at a gentle heat, before moving the flask. Of course, the, less sulphur the ore contains, the quicker the operation of attacking can be pushed for- ward. Should the ore be extremely difficult to clean, and the operator in a hurry, it may be effected by repeated small doses of nitric acid and drying off to a thick paste on the sand- ASSAY OF COPPER. 17 bath ; but it is always best to let the ore digest and clean itself. In filtering, do not employ too large a filter, as that necessitates extra washing. Take care to well wash the upper edge of the filter, and always wash from the top to the bottom. The object of drying the filters on the sand- bath is to see whether any cupreous solution has been left on them : should this happen, of course the copper will leave a stain on the filter. This is one of the most fruitful sources of error with beginners. Generally speaking, it is better to let the filtrate run nearly through before adding more or washing down. The solution in the precipitating flasks must have a certain degree of concentration, in order that the copper may be precipitated in thin leaves and not in fine powder, which it would be if the solution was too weak. This fine powder floats on the top, and gets both oxidized and lost ; and, besides, the precipitation takes place slowly and is not complete. The wire ought to be pf the same tem- c 1 8 THE PRACTICAL ASS AVER. perature as the solution, more or less : if the wire is too cold, the first copper precipitated sticks to it, and prevents the rest from being thrown down. The wire must be of the very best quality, and not liable to chip, or else minute portions come off in the acid solution, and are subsequently weighed up with the copper. It is better to test every fresh batch of wire before using it. Remember not to keep the iron in long after the copper is pre- cipitated, or an excess of salts of iron is formed which is very difficult to wash out. Seven or eight washings are generally required for each assay. The first washing comes off clear, and the next two come off red and turbid, producing specks, some of which float on the top, and some mix with the precipitate : this results from the facility with which the salts and subsalts. of iron are decomposed. • While the liquor remains acidulaited, as always hap- pens at the beginning of the operation of washing, this • decomposition does not take place, but afterwards it does. A few drops ASSAY OF COPPER. .19 of muriatic acid are added to dissolve these subsalts of iron. If the precipitation has been carefully conducted, one addition of acid will be sufficient, if allowed to stand a few minutes. After weighing, the -capsules must be ex- amined ; if quite, or very nearly clean, the assay has been carefully conducted as far as the washing is concerned, but if the iron and acid, has not been washed out, a yellowish^ black stain will be observed round the place where the copper was dried, deeper in pro- portion to the quantity of iron. In this case allowance must be made for the extra weight of the iron, which some assayers can estimate to a nicety. Speaking generally, it would require a very deep stain to warrant a reduc- tion of 3-ioths, and i-ioth usually suffices. If the assay substance is very rich, we may prevent in a great measure the annoyance of having an excess of iron and acid in our solution by the following method. When if is judged the precipitation is nearly com- 20 THE PRACTICAL ASS AVER. plete, take out the wire and clean off the copper ; put it (the wire) into another evaporat- ing dish, and pour the nearly exhausted liquid into it ; add a few drops of acid, and boil up, to extract the lost particles of copper. Throw away the liquid, and wash the few grains of copper into the flask with the rest. The great bulk of the copper is thus preserved from the injurious effect of the salts. This, however, will not be necessary' after the operator has had a little practice in estimating the proper strength of the solution. To put it plainly, the solution ought to stand about half an inch in height in the precipitating flasks for an ore of 20 per cent. In spite of all precautions a small portion is sure to pass into the state of protoxide, but this gain in weight is compensated by a small loss in metal which remains in the solution un- precipitated. I have been purposely exact and quite plain in my description of the above process, as it is the one undoubtedly, most suited to tlie ASSAV OF COPPER. 21 requirements of the general practical assayer, and is at the same time the most reliable and exact. It has often been condemned for its slowness, whereas, when well conducted, twenty or twenty-five assays can be made by one assayer and an assistant. It requires no heat beyond that of an ordinary kitchen fire, and possesses the great advantage of cleanliness. I shall now proceed to describe a modifi- cation of this process, suited to those assayers who may not have access to a large sand- bath,- or who are engaged in exploring, &c. As many as four assays at once can be taken by the following method, which is even quicker and preferable (for a small number of assays) to the method with a sand-bath. APPARATUS REQUIRED. The same as for the preceding operation, with the exception of a brazero. This con- sists of a large iron dish about twenty inches wide on top (rim and all), and fourteen inches wide at bottom. A flat rim runs round the 23 THE PRACTICAL ASS AVER. top, two inches wide. In the bottom are three or four holes, half an inch in diameter, and the whole thing is supported on four legs four or five inches high. Nos. 4 and 5. — Brazero and gridiron for taking four copper assays simultaneously. A sack of good charcoal ; a pair of small cork- armed iron tongs for the flasks; a common gridiron, with four legs, of such a size that the legs are supported on the rim of the brazier ; two halves of a brick and a tile or two, com- plete the apparatus. The first thing to do is to light a charcoal fire in the brazier and wait till it has quite burnt out to white ashes. When about half full of ash another fire is to be built on the top of it, and the brazier is always to be ASSAY OF COPPER. 23 kept half full of ashes. They make one of the best sand-baths in the world. Having made the fire, place the gridiron on the rim, and your flask or flasks on the top of it. If the fire is too hot, or the ore too hard to be attacked quickly, place a piece of thin tile under the flask, which will moderate the heat. When the assays are cleaned off from sulphur, the gridiron is re- moved and the assays placed round the fire, while they are one by one evaporated to dryness by means of the cork-armed tongs. An assay can be dried off much quicker by this means, and a good flask never breaks through contact with the hot embers. The gridiron must be replaced for the filtering, precipitating, &c.; the precipitating flasks can be subjected to a gentle heat by placing a brick or a thin tile under them, ac- cording to the degree of heat required. The wires when required to be heated can be placed at one of the corners of the gridiron. Four assays can be taken in this way at the 24 THE PRACTICAL ASS AVER. cost of about 2d. for fuel, and quicker than on a regular sand-bath. Indeed those Chileno assayers who only have four or five assays to do, prefer the brazero. Sefior Domeyko advises for precipitation small bars of iron three inches long by half an inch square. These bars must be slightly curved so as to rest on the tips, exposing the whole surface to the action of the acidulated solution. One advantage in this method is, that the copper comes off in half-inch leaves, making it much easier to wash, and not being so liable to waste. The great disadvantage is that the bar is liable to slip and break the flask. A pair of ivory or bone-tipped tongs must be used to introduce the bar into the flask. Some assayers dispense with the pre- cipitating flask altogether, filtering the solution direct into the capsule, and precipitating the copper also in the same vessel. It is better to use a flask, as the copper solution splashes up on the side of the capsule, and it is not so easy to manipulate as a flask. ASSAY OF COPPER. 25 Although the above process is sufficient for all purposes that a practical assayer is likely to require, still we may as well give the two following accounts, condensed from the Chemical News. The first is for the assay of sulphurous ores, as copper pyrites, by Mr. F. P. Pearson ; and the second, for the determination of minute traces of copper, by Mr. J. M. Merrick. Weigh out 100 grains of the ore, and a tea- spoonful of chlorate of potassium, and place the mixture in a porcelain dish. Add enough nitric acid to cover the ore ; heat gently on a sand-bath, and add from time to time small doses of chlorate of potassium and nitric acid till free sulphur is no longer visible. Allow the solution to become cold ; add hydro- chloric acid, and evaporate to dryness, to render the silica insoluble. Add water to the cold solution, and transfer the contents to a beaker. Heat the contents to boiling point ; prepare a strong solution of ferrous sulphate, slightly acidulated with sulphuric acid, and 26 THE PRACTICAL ASS AVER. add to the boiling solution 25 c, c. of this latter, and keep it just on the boil for five minutes. If the reduction is not complete, add cautiously a little of the ferrous solution until the contents of the beaker become almost black, and no gas is disengaged. In order to be sure that all the nitric acid has been reduced, it is better to test a drop with ferricyanide of potassium. Filter the liquid into a beaker, and precipitate with iron in the usual way. It is claimed by Mr. Pearson that by this method the last traces of nitric acid can be removed more quickly and conveniently than by successive doses of muriatic acid, and that the chlorate of potassium oxidises and dis- solves every particle of the sulphur, so that no ore can be enveloped and escape decoin- position. I very much doubt whether the method is quicker. The great point in the process described first is to let the assay stand at least twenty minutes at a gentle heat, and not boil strongly at first. If this is attended to, the sulphur is perfectly bright and clean at ASSAY OP COPPER. 27 the end of half an hour. On the whole, I do not think this latter process is any way pre- ferable to the Chile one. Mr, Merrick's process is as follows : Dissolve the ore in nitric acid ; evaporate to dryness, and heat the residue to render silica insoluble. Add boiling distilled water and ammonia to precipitate and redissolye the copper. Filter, wash, and add sulphuric acid. A stout platnum wire is now hung in the solution, and the copper is plated out on the inside of a platinum dish which forms the cathode of a battery of two small Grove's cells. For the estimation of very small quantities of copper no method can approach it. If nickel is present it can be determined in the same manner, by rendering a sulphate solution ammoniacal with excess of ammonia. There are many other methods of assaying copper ores by precipitation, but as they are either too long or involve use of apparatus which the ordinary assayer is not likely to be able to obtain, they are omitted. 28 THE PRACTICAL AS SAVER. ASSAY OF COPPER ORES CONTAINING ROUGH OR NATIVE COPPER. Sometimes in a sample of ore there remain on the sieve particles of copper which will not pass through. The estimation is effected as follows : The whole sample is first weighed : say it equals 5000 grains. Now weigh the rough copper; |say it equals 3000 grains. Conse- quently the ore and gangue equals 2000 grains, thus : Total sample = 5000 grains. Rough copper = 3000 grains. Ore and gangue = 2000 grains. Now assay the rough copper as usual^-say it gives 98 per cent. : also the ore — say it gives 50 per cent, of copper. So we have 3000 grains x 98 per cent. = 294,000 2000 grains x 50 per cent. = 100,000 394,000 Now divide this product, viz., 394,000, by the ASSAY OF COPPER. 29 total weight of the whole sample, viz., 5000 grains, and the result is the correct per-centage of the ore. In the present case, of course, it amounts to '^= 78-8 per cent. In assaying bar copper or ingots, great care must be taken to get a correct sample. The best way is to empty the packet into a porcelain mortar, stir it up well with a spatula, and then let it fall on a sheet of glazed paper through a wide funnel. Then take your sample by smoothing down the top of the pyi-amid thus formed, and taking a few grains from here and a few from there. It is always best to take two assays of bar or ingot copper. In these assays, always use dilute nitric acid at first, or else the very violent ebullition that ensues might carry off some minute particles of copper. In assaying copper slags, the flask or flasks must be con- tinually kept in motiop, to prevent the substance sticking to the sides, in which case a long time is wasted in boiling it ofl" again. 3° THE PRACTICAL ASS AVER. ASSAY BY MEANS OF STANDARD SOLUTIONS. Of all the methods that have been proposed to assay copper ores by volumetric analysis, only one, the cyanide of potassium method, is unobjectionable. Some are too tedious, some inaccurate. The cyanide assay is both quick, easy of execution, and accurate ; consequently, this is the only volumetric method that will be described. APPARATUS, &e., REQUIRED. Some boiling-flasks, similar' to those used in the precipitation process. Some graduated burettes, of looo grains capacity, divided into twenty equal parts of ten divisions each, or two hundred divisions in all. The burettes made by Messrs. Jackson, of Barbican, are isspecially suited to this purpose. Some black india-rubber tubing, glass jets, and pinch-cocks, for the above. Some cyanide of potassium : the crystallized cyanide sold by Johnson and Sons, London, is ASSAV OF COPPER. .31 by far the best for this purpose. It is purer, takes up much less bulk in travelling, and is much clearer in solution. Its relative price is about the same as the ordinary cyanide. The most convenient and the cheapest way of arranging the burettes is as follows : Get two square uprights of common deal, and two pieces of wood four inches wide, and thirty inches long, one being half an inch, and the other one-eighth of an inch thick. Cut two square holes at each end of these pieces, and fix the thinnest one about seven inches from the bottom of the square uprights, and the thickest one near the top, two or three inches less than the length of the burette. At the bottom of the uprights may be nailed two square pieces of lead as stands. Five holes, the size of the burettes, must be bored in the upper slip of wood, and five corresponding ones, but of much less diameter, in the lower. To arm the burettes, cut off three inches- of india-rubber tubing, and screw one end on to the end of the burette previously moistened in 32 THE PRACTICAL ASS AVER. the mouth, and fix one of the glass jets into the other. Three inches is quite sufficient, as too long apiece "flops" about, and scatters drops of the solution. The burette may now be slipped in at the top hole, and the point of the burette passed through the smaller one. The burette is prevented from passing quite through by its shoulder resting on the edge of the hole. The pinchcock may now be attached, and the appa- ratus is ready for use. No. 6. — Method of arranging five or more burettes. The cyanide solution is made by dissolving such a quantity in pure distilled water as shall be equal to a -given quantity of pure copper. ASSA Y OF COPPER. 33 . As, however, it is best to be exact in descrip- tions of processes, I shall take five grains of copper as the standard, to equal which about two thousand grains of ordinary cyanide are placed in a large green or blue ammonia bottle, and the latter filled with water ; the liquid is filtered if necessary. Of course some cya- nide is stronger than other. To prevent the decomposition of the salts, a fluid-ounce of ammonia is added to the solution of cyanide. Suppose five samples are to be assayed, the operator proceeds as follows : The packets of ore are to be numbered as before, and six boiling-flasks are taken and marked correspondingly. A piece of the purest electrotype copper that can be obtained is cleaned in dilute nitric acid, dried, and weighed roughly on a balance to within a fraction of five grains. It is now weighed on the most accurate balance obtainable exactly to five grains. The most convenient form of pure copper for this purpose is sheet or leaf copper. A per- D 34 *THE PRACTICAL ASS AVER. fectly clean boiling-flask is taken, and the piece of copper dropped in. A small quantity of dilute nitric acid is now added, and the copper is dissolved. A few drops of water are added, and the solution boiled to expel nitrous fumes. It is cooled in a bucket of water, and the flask filled one-third full of water, and made quite cold. Three or four teaspoonfuls of ammonia are now added, when a deep-blue solution is the result. If not quite cold, dip the flask in cold water, or, still better, let a tap of cold water run over it. This forms the test assay. Weigh out twenty-five grains of ore (or twelve and a half grains, if very rich) from each packet, and place them in the corresponding flasks. Add about two teaspoonfuls of nitric acid, and digest till the ore is quite decom- posed : dry off", moisten with nitric acid, dilute with water to half the flask and add ammonia in excess. Wait till the assays are quite cold, and then proceed as follows : — SKake-up the bpttle of cyanide solution tojjen- der the contents homogeneous, ^and pour out ASSAV OF COPPER. 3J into a common milk -jug a pint, more or less. Rinse out the burettes by running a little cya- nide through them ; then place the pinchcocks on, and fill them all up to the very top, taking care not to let any run down the outside. Wait till all the bubbles rise to the top, and then let the liquid gradually fall down to the level of the zero. Two portions of the liquid will be observed, like the convex and concave sides of a crescent. It is better always to read the burette from the lower edge of the circle, and not from the tips of the crescent. Some assayers employ a " reader," but this is quite unnecessary. Take your pure copper solution, and run in from a burette seven divisions, more or less; agitate the solution well, and allow it to stand for five minutes. Now add two more divisions ; agitate and allow to stand again ; and so on, two divisions at a time, until about eighteen divisions are run out. The ammoniacal solution begins now to assume a purplish hue, and the cyanide must be added, a few drops at a time, 36 THE PRACTICAL ASS AVER. till a decided lilac tinge is produced. The ope- rator must be careful now, and when only a faint lilac tinge is left, the assay is finished. This tinge ought to disappear, and the solution appear quite white in about ten minutes after the last addition of cyanide. About twenty minutes is the best time to be consumed in getting the required tint. In a burette of twenty divisions, this tint ought to be obtained as near as possible at the twentieth or last division. A piece of folded white paper, placed under the flask, greatly facilitates the estimation of the colour. The ore solutions are now taken and placed under their respective burettes ; the cyanide solution is added, say four divisions at first. The bottles are well agitated for at least a minute, a circular twirl given, and the con- tents allowed to settle. The deepness of the blue colour is now observed, and, according to its depth or faintness, the cyanide is added slowly or quickly. After each addition of cyanide the contents of the flask must be well shaken, to make sure of all the copper beino- ASSAY OF COPPER. 37 taken up. When a faint lilac tinge similar to that of the pure copper test is obtained, the assays are finished. Supposing that the pure copper solution required exactly twenty divisions of the cyanide to decolorize it, and No. i of the ores required seventeen divisions, the per-centage of the ore may be read off according to this formula : — 20 : 5 : : 17 in 25 grains of ore. 17 2o;85 4-25 4 17.00 per cent, of copper. This saves all trouble of calculations, &c. The solution may be got very easily to this standard by adding either water or cyanide, according to its strength, and, as it is subject to a very slow decomposition, a large quantity, like an ammonia bottle full, need only be tested once a week. 38 THE PRACTICAL ASS AVER. Any number of assays can be taken by this method in half an hour. REMARKS ON THE ABOVE PROCESS. The above method, simple as it appears, is most extremely difficult of execution by an inexperienced operator, who may easily make an error of two or three per cent. This arises from a variety of reasons. Nitrate of copper produces a pure blue, but sulphate and chloride of copper commu- nicate a lilac and greenish hue respectively. It is better not to make use of either hydro- chloric or sulphuric acid in dissolving the ore. After an assay has stood some time, it occa- sionally assumes a greenish hue, not arising from the presence of foreign metals. In this case add a few drops of nitric acid and a tea- spoonful of ammonia, and agitate. The more ammonia that is used, the more intense is the colour, and a great excess of ammonia sometimes causes a greenish blue tinge to be observed. Only just sufficient ASSAY OF COPPER. 39 ammonia is to be added as will cause the solu- tion to assume the blue colour. Solutions poor in copper, such as slags, &c., nearly always assume a greenish tinge. Nickel, cobalt, manganese, and zinc interfere with this method of assay. Manganese may be removed by the addition of carbonate of potassa, when present as oxyde. The solution must be heated and filtered from the precipitate. Jacquelain says that the addition of white pulverized marble to the solution until all action ceases, and then warming the solution in a sand-bath, renders the presence of nickel and cobalt quite harmless. The solution is now filtered, washed, the residue dissolved in nitric acid, and treated with ammonia as before. Instead of using ammonia fortiss it is recom- mended to use as the ammoniacal agent a saturated solution of carbonate of ammonia. Great care must be taken in adding this liquid, as the bubbling and effervescence are very violent. The foreign metals are neutralised to 40 THE PRACTICAL ASS AVER. a great extent by this means, but a very fine precipitate is formed, which takes a long time to subside ; this prolongs the determination of the last few tenths of the cyanide solution. It is always advisable not to filter the ore solu- tion if possible, as washing the filter greatly increases the bulk of the ammoniacal liquid. Indeed, in all assays, transferring from one vessel to another, either by decantation or otherwise, is greatly to be guarded against. It is far better, however, on perceiving the presence of the interfering metals, to reject the solution altogether, and assay the ore by the precipitation process. Zinc, in small quantities, does not seriously affect the accuracy of the assay, as may be easily proved by one or two experiments on copper precipitated by means of zinc. A large quantity, however, interferes with the decolorization. Oxyde of lead produces a slight milky tint to the solution : this rather facilitates than disturbs the final estimation. ASSAY OF COPPER. 41 BLOWPIPE ASSAY. A few grains of the ore are finely pounded up, and carefully roasted in a small porcelain dish over a spirit-lamp. A small quantity of phosphor salt is melted on the platinum wire, and dipped into the powdered ore ; the whole is now fused into a bead. Repeated doses of bisulphate of potash are added to the bead, until the latter is saturated. It is ground in the porcelain mortar, and the contents rinsed into a small evaporating dish, and dissolved in boiling water. It can now be tested with ferrocyanide of potassium. If copper is present, a red precipitate is produced. If a very small quantity of copper only exists in the ore, a brown precipitate is thrown down ; and if no copper, and only a small quantity of iron is present, a bluish-green precipitate is exhibited. The phosphor salt is added for the purpose of making the effect of the bisulphate of potash more effectual. 4.2 THE PRACTICAL ASS AVER. This method is peculiarly applicable in cases- where the explorer wishes to detect or suspects the presence of copper in minute quantites in iron pyrites. Red and black oxyde of copper, the car- bonates blue and green, give the usual indica- tions with the borax bead, and a metallic globule on being reduced with carbonate on charcoal. Copper pyrites and grey copper cannot be distinguished by the usual borax and. charcoal tests. The former can be distinguished by its being softer than iron pyrites, with which it is often confounded, by its forming a blue solution with nitric _acid, and giving off an odour of sulphur before the blowpipe flame. In the case of the carbonates, the estimation by the blowpipe may be most effectually made as follows : Choose a piece of charcoal free from cracks, and scoop out a small hole in the side. Make up a mixture of one part of the mineral to be tested, and four parts of carbonate of soda, ASSAY OF' COPPER. 43 forming in all a piece the size of a pea. Place it in the hole, and very carefully direct the blowpipe flame upon it ; when the piece appears settled, the reducing part of the flame may be directed upon the bead, and as hot a blast as possible kept up. When the metal is obtained as a globule in the charcoal, the assay is finished. Extremely rapid and accurate results may be obtained by this method. Supposing a mineral is suspected to contain copper in small quantities, say five per cent., a good way to proceed is as follows (this method of assay cannot be applied in the case of pyrites) : Mix a little of the ore with carbonate of soda, and place the mixture on a sound piece of charcoal. Add soda till the charcoal has absorbed the whole mass ; cut out the surrounding charcoal and assay piece, and grind up the whole in the agate mortar with water ; decant off the charcoal, and grind alternately, till all the extraneous matters are rejected. If any copper is present, even in 44 THE PRACTICAL ASS AVER. minute quantities, it will be seen in small flakes coating the mortar, or settled at the bottom in fine powder. Great care must be taken to thoroughly reduce all the metal in the assay piece, by keeping up the flame to its highest pitch, and attacking every part of it, and also in decanting the ground charcoal and flux. The black and red oxydes, and the car::, bonates blue and green, can be easily dis- tinguished by the above tests. Grey copper and copper pyrites, however, give no indication either with borax or carbonate of soda. The detection of copper by borax colouring the bead is as follows : The end of the platinum wire is bent into a loop, and a small piece of borax fused on it : more borax is added, and so on till the loop is filled with a bead of fused borax. This bead is then heated gently, and dipped in the powdered mineral to be tested, and kept in the oxydising point of the flame, in as hot a flame as possible, for some little time. The colour imparted must be watched, both when the bead ASSAY OF COPPER. 4S is hot and when it has cooled. If no colour is imparted, a fresh supply of mineral may be taken, but if the borax is completely saturated with the colour, so as to be dull, the experi- ment must be repeated with a smaller quantity. The bead may then be placed in the reducing part of the flame ; care, however, must be taken, in this latter case, not to allow the bead to cool too suddenly, or it would become oxydized. A good plan is to place it in the flame of the blowpipe lamp for a few moments and cool it gradually. If copper is present in the mineral, the colour of the borax bead will be red in the reducing flame, and green and blue, when hot and cold respectively, in the oxydizing flame. ASS A Y OF SILVER. All silver ores may be assayed in three ways. I. By running them down in a crucible with a suitable flux. 2. By scorification. 3. By the blowpipe. We will take the three processes in order. I . Running down the ore with a flux. Minerals composed of copper and silver can be assayed either as silver or as copper ores, as the lead button that is obtained from the fusion with litharge is capable of being cupelled if it has a suitable proportion of lead to the copper. In the case of argentiferous regulus coming under the operator's notice, the mineral must be roasted previously. Metallic lead might be added as the lead-producing flux, but it is always preferable to use litharge free, or nearly free, from silver as the agent. It is easily mixed and disseminated through the mixture. The most convenient reducing agent is char- ASSAY OF SILVER. 47 coal, reduced to the finest possible state of division. The fusing fluxes most commonly used', and also the most convenient, are car- bonate of soda and borax. The four substances — viz., litharge, carbon- ate of soda, borax, and charcoal — are all that are required for any silver ores that are likely to fall under the notice of the practical assayer, with the exception of galena, the assay of which will be described separately. The first thing to do is to assay the litharge. To do this, take 1,000 grains and place them in a large warmed crucible, with 200 grains of carbonate of soda, and 35 or 40 grains of charcoal ; intimately mix with the spatula, and cover the whole with a layer of carbonate. Fuse at a low heat, and when fluid pour out the contents into a mould, and reserve the button of lead for cupellation. The amount of silver must be noted, and the corresponding amount deducted from the actual assay. Having determined this, proceed as follows : 48 THE PRACTICAL ASS AVER. Place two crucibles to warm over the cover of the furnace, and, meanwhile, weigh out the following mixture : Ore . .100 grains Litharge . 400 „ Carbonate 350 „ Borax. .150 „ Charcoal . 20 „ Intimately mix the whole on a sheet of glazed paper, and shoot the mixture into the warm crucible ; shake the contents even, and take 50 grains or so of litharge on the point of a spatula, and powder over the top of the contents. Pre- pare two crucibles in this manner. Place the crucibles in the furnace, side by side, and pack the coke round them till they are completely enclosed. Take off one of the bricks at first from the top of the furnace, and fuse at a low heat at first, winding up with a full red heat for five minutes, to thoroughly fuse the slags : the whole operation is complete in about twenty or twenty-five minutes. ASSAV OF SILVER. 49 The great point to be observed in this part of the process is to keep the heat as low as possible at first, as silver lead is sensibly- volatile at, a high temperature. When the contents of the crucible, which can be viewed through a small chink between the bricks, flows quite smoothly without bubbling up, the crucible must be seized with a pair of furnace tongs, tapped once or twice on the side of the furnace to settle the contents, and poured immediately into a hot mould, previously rubbed with common blacklead to prevent the lead sticking to it. Allow the mould to stand for five minutes, and then invert the contents into a bucket of cold water. Allow to cool, and the slag will then come off with one or two taps of a hammer on the edge. The slag detaches itself much easier if the button is plunged into cold water before it is quite cooled. The lead button must now be cleaned by holding it edgeways on an anvil and tapping it gently with the hammer, occasionally dipping and cleaning it in water. E so THE PRACTICAL ASSAYER. Hammer it into a thick cube, and scratch on it the corresponding number of the packet sent to assay, and set it aside for cupellation. If the ores should contain antimony,. &c., the button may come out brittle, and perhaps break up under the hammer; if so, clean the button as carefully as possible and place it in a scorifier, and add about half its, weight of granulated lead and scorify as usual, to be hereafter described. The above mixture will generally suffice to run down most of the silver minerals that are likely to come under the assayer's notice, though, of course, the quantity of lead must be varied according to circumstances, as in argentiferous regulus and galenas. Sometimes, when the ore is very hard, the flux will not flow smoothly, but appears viscid and thick. In this case some niixed borax and carbonate may be placed in a copper shoot and projected into the crucible, and the heat urged on for a few minutes. Argentiferous Regulus is assayed as follows : ASSAY OF SILVER. 51 Calcine the ore first " sweet," or quite free from sulphur. Take 100 grains of the ore, and add the foUpwing mixture : Litharge . 1000 grains. Carbonate 350 „ Sand . . 100 „ Borax . . 150 „ Charcoal . 35 „ Intimately mix with the usual precautions. The sand is added to prevent the large quantity of litharge from attacking the pot, as it attacks the sand instead. A double quantity of litharge is added, in order that the excess of lead in the button may pass the copper contained in the regulus into the cupel. If a small quantity of lead, or, in other words, a small button, was cupelled, the copper would be so concentrated that the assay would not yield a silver button, but a silver and copper one, owing to there not being sufficient lead to pass the copper. This will be'treated of pre- sently under the description of the assay of 52 THE PRACTICAL ASSAYER. alloys. If there is a difficulty in procuring borax, the same quantity of green bottle-glass answers the same purpose. Galena, or Silver Lead, is assayed in pre- cisely the same manner as if it was being assayed for lead only. The two following methods are the best, and, if carefully per- formed, very little lead is lost ; No. I. — Ore . . 400 Carbonate 350 Borax . 50 Argol . 30 Intimately mix, and cover the top with some of the mixed carbonate and borax. Then take three large nails, or, better still, three pieces of hoop iron, and push them down to the bottom of the mixture in a triangular shape. Place the crucible, iron and all, in a furnace, and fuse at a low heat for twenty minutes. Give .about two minutes' strong heat at the end, during which you can Iremove the pieces of iron one by one, tapping them and washing them in the ASSAY OF SILVER. 53 molten metal, to' prevent globules of metal sticking to them. Then pour as usual. No. 2. — Ore . . 400 Argol . . ioo Carbonate 400 Borax ; 200 Mix and cover as before ; add the pieces of iron, and proceed exactly the same as in No. i. If carefully performed, both these methods yield excellent results, particularly the first one. Of course, if the galena is extremely rich, half the quantity of ore may be taken, and the requisite proportion of granulated lead added to the assay. SCORIFICATION. We are enabled by this proems to obtain an alloy of lead capable of being cupelled. .The principles are exactly reversed; for whereas in the crucible assay the object is to reduce the oxyde of lead to a metallic state, in the process of scorification the metallic lead is oxydized by being roasted in contact with the 54 THE PRACTICAL ASSAYER. air. Scorification is the most convenient, cheap, and correct way of assaying silver ores, when properly performed. METHOD OF ASSAY. The scorifiers shbuld not be of the usual shallow shape, but deeper in proportion to their width: in fact "the best form- of scorifier may be compared to the end of an ^g^. The object of having them this shape is that the bath of molten lead at the bottom is always covered and protected by the slags on top during the whole process of roasting. The scorifiers should be well dried before using them for the assay. Proceed as follows : Mix 300 grains of granulated lead with 50 grains of xhtt ore to be assayed. Place the mixture in a scorifier, and cover over with 300 grains more of granulated lead : over the whole put as much borax (anhydrous) as you can, and place the scorifier in the strongest heat of a good muffle for at least thirty minutes. If the slags, are not liquid, add a little more borax, and ASSAY OF SILVER. 55 Urge on the fire for ten minutes more. When the slags are quite liquid, which generally occurs in about forty minutes, wrap up four or five grains of powdered anthracite in a piece of paper, and drop it into the scorifier while in the muffle. Wait till the anthracite has burnt off, which will be in about five minutes, and then pour immediately into a mould. The object of adding the anthracite is to reduce any metal that may exist in the slags, and thus save 'the trouble of assaying the slags subsequently. In case the operator has a chloride of silver ore to assay, carbonate of soda must be added to the mixture, to prevent sublimation. In case argentiferous- regulus is th& sub- stance under consideration, looo grains of granulated lead must be employed to the same quantity, viz., 50 grains, of the ore. Generally speaking, 'about tenor twelve, times the amount of lead is required, but galena scorifies with a very much smaller proportion, three or four parts being sufficient. Very often 56 THE PRACTICAL ASS AVER. it happens that the contents of the scorifier will not start roasting, but the slag sticks and does not uncover ; this arises from the furnace being too cold ; a little glass of borax wrapped up in paper and dropped in generally sets the assay going. When borax is used the slag surrounds the metal like a ring, which is continually diminishing, and at last the whole bath is com- pletely covered with liquid slag : the fire ought then to be pushed on to its hottest. There ought always to be sufficient lead left to form a slag, which completely covers the button when this latter is poured out. There is no difficulty in performing this method of assay ; the great points are to have the furnace hot enough, and not to pour the contents out until they are quite liquid.- When poor ores are under treatment, the crucible method is the best, as only 50 grains can be used in the sco'rification process, and, consequently, unless two assays are taken simultaneously, the resulting button of silver is small ; but when very rich ores, and more ASSAV OF SILVER. " 57 particularly rich copper ores, are operated upon, scorification is very useful, as in the crucible method much copper is reduced with the lead, so that a very large quantity of lead" is neces- "sary in order to pass the copper iiito the cupel. The muffle cannot -well be too hot for this operation : the right heat is when you can just see the back of the muffle whitish. The most common fault is having the muffle too cold. Supposing that the operator has to determine the silver contents of copper regulus ; the best way of proceeding is as follows : Warm two scorifiers ; weigh out 50 grains of the regulus into each, with 1000 grains of gran- ulated' lead and some borax : scorify as usual, and pour. Place the two buttons thus obtained in a fresh scorifier, and scorify till they are com- pletely covered with fused oxyde. Then cupel the resulting button. 58 THE PRACTICAL ASSAYER. CUPELLATION. This operation, depends on the property a cupel has of absorbing the oxyde of lead pro- duced during the operation, leaving only the gold and silver remaining. The first thing, to do is to thoroughly dry the cupels, which can be conveniently done by placing them in the furnace while it is heating: if not thoroughly dry, the contents of the cupels will spit, and project portions of the metal out on the floor of the muffle. They are best placed topsy-turvy when dry- ing. When the muffle is at a cherry-red, and no hotter, they can be turned right side upwards, and the buttons introduced one by one. Close the door of the muffle to start the buttons, or make them uncover; occasionally they will not uncover for some time. In this case a piece of thick brown paper placed on the top, or a piece of burning coke generally suffices to start them. When they are well started, open the door of the muffle and allow ASSAY OF SILVER. 59 the cupellation to proceed at as low a tempera- ture as possible. When the briglitening. takes place, close the door and give a good strong heat for a minute or two to disengage the last traces of lead from the button. Take hold of the cupel with the tongs and draw to the mouth of the muffle, and allow the bead to cool gradu- ally. If it is a good-sized bead, and the cupel is takeri too suddenly from the muffle, the silver cools more quickly on the surface, and, contract-' ing on the outside, squeezes the liquid metal inside, which forces a way out for itself. When this happens, the bead is said to "vegetate." Supposing that the bead has cooled satisfac- torily, take hold of it with a pair of close pin- cers, and examine it. If it is round, bright, and white above, crystalline below, and. easily de- •tached from the cupel, the assay may be con- sidered to have passed accurately. It is now to be strongly squeezed with the pincers, which will h^ve the effect of detaching all particles of the cupel which would otherwise adhere to it. A cupel ought to be 30 or 40 grains heavier 6o THE PRACTICAL ASS AVER. than the button to be assayed. The button does not represent the actual amount of silver in the ore, as a loss, greater than that in the large way, invariably occurs in cupellation. This loss arises principally from volatilization and absorption into the cupel. The first may be partially prevented by taking care not to cupel at a higher temperature than is abso- lutely necessary; and the second by attending to the quality and texture of the cupels. These losses, however, if the operation is carefully conducted, are not counted in com- mercial assays. By the colour of the cupel after the operation is finished we may judge of the foreign metals contained in the mineral. Lead gives the cupel a sulphur colour ; copper, a dirty-brown shade ; bismuth, an orange-sulphur. Tin and iron give" a black, and grey slag, which stands like a ring round the edge of the cupel. Zinc leaves a thick sulphur circle, and gives off dense white fumes, and occasionally spits and bubbles. Antimony very frequently cracks the cupel ; in this case, ASSAV OF SILVER. 6i as before stated, the button must be scorified with rather more than half its amount of lead, and then cupelled. ALLOY OF SILVER AND COPPER. The determination of this alloy is estimated by cupellation. The chief point is, as in the case of regulus and rich copper ores, to have sufficient lead to pass the copper into the cupel. In case we are uncertain what the quantity of copper is, we can be sure of succeeding by using from twelve to fifteen parts of lead, .which is the quantity required to pass pure copper. For the assay of standard silver — a florin, for instance — about six times the amount of lead does very well ; but it is always better to add a little more, and make sure. An alloy of ^ silver requires about eight times the amount of lead; ^ of silver, about twelve times ; and, after that, about fourteen or fifteen times the amount, up to pure copper. It is best to make a rough assay first of all, if the 62 THE PRACTICAL ASSAYER. Standard of the alloy is not known, by cupelling 5 grains of the alloy with about 50 grains of pure test lead, and noting the loss of -weight in the resulting button. The actual assay can be made as follows : Weigh off twelve grains of the alloy on the most delicate balance that is at hand ; then calculate the amount of lead requisite for the passing of all the copper, and place part of it (the lead) in a cupel in the furnace, with all the precautions already pointed out. When the lead is well fused, wrap up the piece of alloy in the rest of the lead, and drop it in the molten metal. Cupel as usual, and reserve for weighing. Now weigh off twelve grains of silver that is standard. Put §.bout sixty grains of lead in a cupel, and cupel the silver as usual. Then weigh both the buttons. If they both weigh exactly alike, the alloy is standard. If it is I dwt. less, it is called i dwt. less than standard; if more, it is called i dwt. more than standard. In large works it sometimes occurs that ASS Ay OF SILVER. 63 copper bars or ingots may contain silver; with so large a quantity of copper it is in- convenient to cupel. The mode of assay is best performed as follows : Weigh off three pieces of about fifty grains each, and place them in three scorifiefs, with the usual precautions ; scorify to the extreme limit, and place them altogether in another scorifier ; scorify again as usual, and cupel the resulting button. Of course borax must be added as usual, as well as six hundred grains or so of pure lead. AH native silver, that which remains on the sieve during the sieve- ing of rich ores, rough silver, &c., may be all most conveniently assayed by the above scorifi- cation method. Alloys of platinum, silver, and copper are not likely to fall under the every-day assayer's notice, and are therefore unnoticed. Assays of alloys of silver and gold will be noticed under " Gold Assaying." - 64 THE PRACTICAL ASS AVER. LEAD TABLES FOR SILVER CUPELLATION. looo parts of fine silver require about 3 times of lead. 95° » » » » J 7 >> » 9 » .» 10 » )i '* » )) 14 » » 17 » » In gold assays, about double the above quantities of lead are required.. 925 900 850 800 700 600 5C0 or less GENERAL OBSERVATION ON THE ASSAY OF SILVER ORES. All silver, and especially gold ores, which contain a large proportion of sulphur or arsenic • or- antimony, should be roasted. In the case of sulphur there is danger of oxysulphurets forming and conveying portions of the noble metal into the slag along with them. No par- ticular care is required in roasting ores. The best way to effect it is to half-fill two cruci- ASSAy OF SILVER. 65 bles with the ore, and place them on the top of the coke in the reducing furnace, or in a common fire, and keep continually stirring the ore with an iron rod. Roast slowly at first, and, after no more dense fumes are given oif, heat the contents to a dull red heat, till they are quite " sweet." If much arsenic or anti- mony is present, a little finely powdered charcoal is added to reduce the arseniates or antimoniates. In the case of galena, which, of course, is very fusible, some fine sand had better be mixed with the ore previous to roasting. In scorification it is best to give not too strong a heat at the commencement. At first the ore will be seen floating about on the top like a small island ; when this disappears and is melted, the slag rises to the top and encircles the bath of molten metal like a ring. During this period the heat ought to be raised, and may be still further increased to the end of the operation." About sufficient borax to well powder over the mixture must be added 66 THE PRACTICAL ASSAYER. at first, and, if the fusion seems to stick, a little more must be added in a piece of paper. It is as well to add a small piece of glass of borax at the end of the operation to thoroughly fuse the slags. In cupellation a button of lead about three hundred grains in weight is the best size for operating upon. In case the button of silver is very large, great care must be taken in cooling it, else it will "spit." The proper heat for cupelling is when the assay just passes well and no more : towards the end of the operation the heat may be increased. It is generally recommended to prefer a high heat and quick cupelling to a low heat and a lengthened one. This is a great mistake, as silver in conjunction with lead is sensibly volatile at a high temperature. The poorer the button is in silver, the higher the temperature may be kept, as there is obviously less silver to volatilize. Occasionally the button "stops, or, as it is called, suddenly " freezes : " this is nearly ASS Ay OF SILVER. 67 — ■ \ . k — , always due to too little heat being employed in the furnace, but of course never happens with ordinary care. If it does happen, unless great haste is needed, always cupel afresh. Some assayers close the door of the muffle when cupelling, but it is always better to have the door partly open during the operation. On detaching the button, if it comes off" extremely easily, and is bright below, it is sure to contain lead, and should be rejected. If, however, it is flat and not roimded nicely, it has not had sufficient lead. In running down ores in the crucible method, care should be taken not to employ too much charcoal ; otherwise the slag comes out black, and retains portions of the silver. One part of charcoal to twenty-five of litharge is the best proportion in ordinary cases. It is alwajrs best to powder over the top of the contents of the crucible with litharge,^ in order that the rain of melted lead may pass through the contents and take up every particle of silver contained in the ore. Directly the con- 68 THE PRACTICAL ASS AVER. * ^ tents of the pot cease bubbling, and flow smoothly, they ought to be poured into the mould. If the borax boils up, the crucible must be lifted gently out, tapped once or twice on the side of the furnace, and cautiously replaced. It will soon subside. REMARKS ON THE OPERATION OF CUPELLATION. The furnace must not be too hot nor too cold. If the heat is high, silver is volatilized, and the pores of the cupel open and absorb minute portions of the metal. If the. heat is too low, the button would be sure to retain minute quantities of alloy or lead. It is diffi- cult to give exact prescriptions for the regu- lation of the heat ; but if the fumes of lead rise straight up to the top of the muffle, the heat is too high, and the cupel must be moved nearer to the door. If, however, the smoke falls to the bottom of the muffle, the heat is too low, and the cupel must be moved further inside the muffle. But we may judge more ASSAY OF -SILVER. 69 exactly of the necessary heat by observing the colour in that part of the cupel which has just been left by the bath of lead. If this appears of a dull reddish colour, the assay is at the right temperature. If the cupel is of a white-red, the heat is too high, and if it is almost black, the temperature is top low. When the assay is half-way finished, it is better to pull it slightly towards the door of the muffle, and, when nearly finished, to place it at the back, and close the, door of the muffle. The button appears dull for some time after it has ceased giving out the rainbow colours, and all of a sudden "brightens." In order that the assay may be correct, the time between this dulness and the brightening should neither be too long nor too short. This time varies with the heat of the furnace and the texture of the cupels. Assays of alloys of ^ generally require about thirty seconds to produce this brightening, while those of ^^ only require about ten seconds. In very compact cupels the brightening shows itself with great facility. 70 THE PRACTICAL ASS AVER. and very quickly; but in this case it is re- quisite to finish them with a high temperature. When a larger proportion of lead is used than is required, the assay experiences a consi- derable loss from being so long in the muffle. If, however, the lead is in too small a quantity, the alloy will retain portions of copper, and the result will be inexact. Buttons that have been cupelled with a great excess of lead nearly always vegetate; they do not shine brilliantly, and are nearly round instead of presenting a hemispherical shape : they, more- over, adhere very slightly to the cupel. The assays, on the contrary, that have been cupelled with too little lead do not brighten, and pro- duce buttons with black patches of oxyde of copper on their surface : the buttons also adhere very strongly to the cupel. As has been already stated, the time of the brightening must not be too long, nor too soon after the dis- appearance of the rainbow colours. When the brightening appears too soon, a round button is rarely obtained : on its surface are seen ASSAY OF SILVER. 71 lustrous and also some dull white spots : the button adheres but. slightly to the cupel, and sometimes has small needle-like holes below, which is a sign that it has not had enough heat at the finish. When, however, the brightening is too long in appearing, the button which is obtained is of an uniform dull white, with black patches of oxyde of copper on its surface, and some small depressions : it adheres very strongly to the cupel, is black below, and frequently vegetates. The signs of a good button are the fact of its being round, lustrous, and crystalized below, easily detached from the cupel, and white on the bottom. Galena may be assayed by submitting it to a direct cupellation, even when the substance contains 2 or 3 per cent, of pyrites or blend. We may effect this without adding lead at all ; but there is danger of the sulphate of lead which is formed covering the bath, impeding the oxydation, and adhering to the button of silver. It is, therefore, better to add lead in 72 THE PRACTICAL ASSAYER. the proportion of 3 or 4 per cent. Galena has a remarkable tendency to throw out sparks when submitted to heat, and we must, there- fore, grind it to a very fine powder in an agate mortar. A few grains are taken, enveloped in a sheet of lead, and introduced into a cupel in a good hot muffle, and the door closed : the instant the mineral fuses, the sub-sulphate which is formed swims on the top of the melted lead. As soon as the contents have acquired the same temperature as the cupel, the muffle is opened, and air admitted, but cautiously, or else particles of mineral are sure to be pro- jected from the bath of lead. Much smoke now arises from the cupel, and the surface of the bath appears covered 'for some time with a solid convex film or crust, which gradually settles down and gets thinner and - thinner. When the smoke diminishes, the temperature may be increased to a considerably higher point than in an ordinary cupellation, in order that the litharge which is formed may melt and pass into the cupel the greater part of the sul- ASSAY Of SILVER. 73 phate of lead which was formed at the begin- ning of the operation. The lead now uncovers more and more, and at length appears brilliant. The ciipellations may now be finished as usual. This method of assaying tolerably pure galena is quick and accurate. In a series of assays instituted by Malaguti, the ley of silver was sensibly greater by this method than by the crucible operation. Domeyko recommends the cupellation of the chlorides of silver thus : — Take six grammes of the chloride, and mix it with ten grammes of granulated lead ; envelope it in eight grammes of sheet lead, and melt it in a small crucible. By this means not more than "004 of silver is lost. He adds, however, that it is better to employ litharge and charcoal, to avoid vola- tilization of the chloride. But, as we have seen, carbonate of soda must be invariably added to these assays, or else a very con- siderable portion of the silver is lost. 74 THE PRACTICAL ASS AVER. ASSAY OF SILVER BY THE WET METHOD. This very ingenious method was invented by the Frenchman Gay-Lussac, It is remarkably simple, clean, accurate, and quick in operation. Cupellation, after all, only gives an approxi- mate result, whereas by this method mathe- matically exact results are obtained. All complicated processes will be omitted in the following description, as the assay can be quite accurately made with the simplest means. APPARATUS, Ac, REQUIRED. Pure rock salt. Pure distilled water, and pure nitric acid. Pure silver. Three or four pipettes accurately marked to looo grains. Six or eight decimal pipettes, marked in ten equal divisions = loo grains in all. Half-a-dozen glass stoppered bottles, having ASSAY OF SILVER. 75 the numbers marked both on stopper and shoulder. Perfectly clean hands, free from perspiration. METHOD OF ASSAY. Take 162 "5 grains of the pure salt, or a little more. Dry it carefully and thoroughly, and weigh the 162 "5 grains accurately before quite cold. Clean out an ammonia bottle, and put the salt in, and add 30,000 grains of the pure distilled water. This constitutes the normal solution. Take 1000 grains of the above solution, and run them in another smaller bottle with a wide mouth, and dilute to 10,000 grains by adding 9000 grains of distilled water. This is conveniently done by buying a bottle of 10,000 grains' capacity. This forms the decimal solution of salt. Take 10 grains of quite pure silver, most accurately weighed, and dissolve it in a little pure dilute nitric acid, and dilute it to 10,000 grains by adding pure distilled water as above described. This forms the decimal solution of silver, ■ 76 THE PRACTICAL ASS A YER. First of all, standardize your solution. To do this, take lo grains of pure silver; dissolve it in pure dilute nitric acid (half water). Blow off the nitrous fumes with a bent glass tube until there are no more of them left : this is effected in one of the stoppered bottles. Now dilute to about a quarter of a pint, and warm the solution till nearly the boiling point. This can be most conveniently done by placing a large saucepan on the fire or brazier, and making the water boil : then immerse the bottle in the water. While the bottle is still in the saucepan, take a pipette full of looo grains of the normal solution, iand, placing the nose of the pipette in the bottle, let the measure run in. Now replace the stopper, and^ taking hold of the bottle with a damp cloth, place your two thumbs on the stopper, and shake violently for at least five minutes. Then give a circular twirl and allow to settle. Now take the decimal solution of salt, and run in lo grains of solution at a time, warming and shaking the bottle after each application. ASSAY OF SILVER. jj Suppose the first six give a precipitate, and the seventh does not, the seventh and half the stxik are not counted. Thus : Normal solution looo Decimal solution 7 1007 Less ... 1*5 1005-5 This represents the standard of the normal solution. Now take as much of the alloy to be assayed as virill equal 10 grains of pure silver, which must be found out by previous analysis. Dissolve in nitric acid, and run in the normal and standard solutions as before, when, of course, the amount of fineness in the alloy can be easily ascertained by a proportion sum. OBSERyATIONS ON THE ABOVE METHOD. Although the above method sounds remark- ably easy and simple, and indeed is so, still a variety of precautions are to be taken. 78 THE PRACTICAL ASS A YER. The nitric acid must be quite pure. The distilled water for this operation ought to be especially kept for this purpose : the first water . that comes over from the still ought to be used for the ordinary purposes of the laboratory, and the succeeding portion kept in clean earthern jars well stoppered. The pure silver for the solution is better obtained from dissolving a florin in nitric acid, adding pure water, and then precipitating with hydrochloric acid till no more precipitate forms. Dry the precipitate in a por- celain dish over a sand-bath, and run down the residue with a small quantity of carbonate of soda in a clean crucible. If the greatest exact- ness is required, dissolve the resulting button again ; precipitate and melt again, when the . silver is perfectly pure. The best way to arrange the bottle of normal solution of salt is to insert a cork fitted with two glass tubes, one bent in the form of a syphon, and fitted with a long piece of india-rubber tubing reaching nearly down to the bench where you are taking the assays, the bottle having been ASSAY OF SILVER. 79 previously placed on a shelf a foot or two above. A small point tube, like a burette point, is now fitted to the end, and a pinchcock fastened on about three inches above the point. When you want to talfe a measure of looo grains of the solution, place the thumb of the left hand on the - outlet of the pipette, placing the fore and middle finger on the shoulder above, thus secur- ing it tight. Now introduce the point of the syphon connected with the bottle, and (having previously well shaken the solution, and run a little through t^he pipette to clean it) run in gradually till an inch past the mark on the neck. Let go the pinchcock and remove the point, and place the forefinger of the right hand firmly on the top of the pipette, removing the thumb of the left. Now wipe the pipette with a clean silk handker- chief, and gradually loosen the tightness of the right forefinger, and allow the solution to run down to exactly the mark-; immediately intro- duce the point of the pipette into the assay bottle as far as the shoulder, and let the solution run in. When all the solution has run, lift the pipette 8o THE PRACTICAL ASSAYER. out, without shaking the superfluous drops off. It is much better for the operator to do this than to try and get rid of all the lost drops of the solution, as a well-made pipette will drop precisely the same for any number of times fol- lowing. The pipettes for the decimal solution are much better when made with the gradua- tions marked the opposite way from that usu- ally pursued, viz. , with the ten degrees at the bot- tom, next the point, and the hundredth division at the top. The reason is that, by immersing the pipette in the decimal solution bottle, you can easily take a measure of a tenth, and let it run out clean into the bottle of alloy, as in the case of the normal solution ; whereas in the pipettes marked in the ordinary manner, viz., with the ten degrees at the top and the hundred at the bottom, you have to run out the solution io a fixed grade ; if you let your finger slip, or have not sufficient practice, you can very easily run past this grade, and spoil your assay. The last drops from this smaller pipette are best blown out into the assay solution with a slight ASSAY OF SILVER. 81 breath, and not left in the norn\al pipette. The bottles used for this assay should be well stop- pered, and of sufficient size to allow the shoul- der of the normal solution pipette to rest there, so as not to waggle about when letting the solu- tion run in. Be careful not to touch the nozzles of the stoppers with your fingers, and always place them, with their ends upwards, on their backs, when removed for the purpose of letting a solution run in. In fact, everything should be touched as little as possible, as the slightest per- spiration will cloud the solution, and very often the acid, or the water, or the test silver is denounced as impure, when the fault is in the clumsiness of the assayer. The hands should be well washed with soap and water before com- mencing this assay, and occasionally wiped on a towel by the operator's side. After each application of solution the bottle must be violently shaken, and replaced in the hot water in the saucepan. If the clear water on settling has a bluish tinge, like quinine solu- tion, copper is present ; but this does not inter- G 82 THE PRACTICAL ASS AVER. fere with the estimation of the cloudiness on the application of the decimal solution. When finished with, the bottles must be well washed with distilled water, and the stoppers replaced. It is best to put them away in a drawer free from dust, &c. Suppose, then, the assayer has three samples to be determined (and unless he is in a mint he is not likely to have more), he will proceed as follows : Thoroughly clean four bottles, and see that the numbers on the stoppers and shoulders agree ; weigh off ten grains of pure silver, and standardize your solution first of all, We will suppose the standard is looo. If the approxi- mate standards of the alloys are not previously known, they must be found out, either by cupel- ling or by the above process. If by cupelling, take about three grains, and cupel with about thirty grains of pure test lead. If by the wet method, its approximate value must be guessed as near as possible, and an amount that would -more or less equal pure silver be dissolved, and ASSAY OF SILVER. 83 its Standard sought by the solutions. Supposing, however, that their supposed standards are goo, 953, 870 : now search in the salt columns for the numbers nearest to them. They will be found to be 11. 10, 10.50, 11.50 respectively. These weights are to be weighed up most accu- rately, and carefully dissolved in pure nitric acid, with all the precautions pointed out. Now take a pipette full of the normal solution, and run in each bottle ; replace the stoppers, and shake violently ; proceed with the decimal solutions : run in each of them a tenth of the salt decimal solution. S uppose a cloudy precipitate falls down from the two first, but not from the last one. Agitate the two first ones well, and replace in the saucepan. We know, by no precipitate fall- ing down in the third one, that we have too much salt solution in already, so we run in a tenth of the silver solution to equalize the tenth of the salt solution already run in. We are now where we started from, and we know that we have to start with the nitrate solution again. Accordingly, we run in a tenth of the nitrate 84 THE PRACTICAL ASS AVER. solution ; it gives a precipitate : another, and the same effect follows ; and so on, five times. Tne sixth, however, does not. Consequently, as before stated, we deduct the sixth and half the fifth, making four and a half run in to be counted. To find out, therefore, the real stan- dard, which was supposed at first to be equiva- lent to 11.50, we seek in the nitrate of silver columns for the number 11.56, and look out in the fourth column (omitting the half for the time), as we have run in four pipettes of the nitrate solution. We find the number 866.1, which, diminished by -5, gives 865.6 as the true standard. Now proceed with the other two. We run in four pipettes of the salt solution : all give a precipitate : the fifth does not. Consequently, we count only three and a half Now look in the salt tables for the numbers 1 1. 10 and 10.50, which represented more or less the required standard of the alloy. We find them 903.6 and 955.2. By adding -5 to these numbers, we get 904.1 and 955.7 as the required standards. ASSAY OF SILVER. 85 It saves time and trouble if we endeavouf always to avoid having to use the decimal solution of silver. We may avoid this by taking particular care to weigh up a sufficient quantity of alloy to equalize pure silver; in other words, to make tolerably sure of having sufficient alloy in our solution for us to commence with the salt solution at once. So much depends on manipulation, that unless a considerable deal of experience has been gained, much handling and equalizing the solutions ought to be avoided. The salt solution should be kept free from dust or dirt, and occasionally tested. By means of the above apparatus, which altogether costs only a few shillings, perfectly accurate results are obtained ; indeed, much more so than by more expeasive apparatus. The filling of the large pipette with the normal solution may be more effectually and easily performed by means of a filter-stand with two ordinary movable wooden filter rings, thus : screw on the lower one tight, and rest the shoulder of the pipette in it, just sufficiently 86 THE PRACTICAL ASS AVER. high from the table to clear the neck of the solution bottle. Now put on the other ring, and slip it over the tube of the pipette, and screw it on tight down on the upper shoulder of the pipette. Your pipette is now held quite fast. Place the point of the jet connected with the india-rubber tube from the solution bottle in the top of the pipette, and fill as usual. This leaves your hands free to manipulate the flasks, &c. ESTIMATION OF SILVER BY THE CHLORIDE PROCESS. There is another method of estimating silyer bullion when alloyed with other metals, viz., by calculating the fine metal by means of its chloride. In November, 1871, an account of it was given by Dr. Busteed, from which the following is condensed : The samples are accurately weighed as usual, and placed in their respective bottles, and li drachms of nitric acid is added to ASSAy OF SILVER. 87 them from a graduated pipette, and trans- ferred to a sand-bath, where the contents of the bottles are completely dissolved. The S.G. of the acid in case of alloys is generally 1 200 ; but when the presence of foreign obnoxious metals is suspected, acid of 1320 S.G. is used. Six ounces of cold distilled water are now added, and subsequently i^ drachms of hydrochloric acid, S.G. 1060. Of course, chloride of silver immediately forms in white curdy clouds of precipitate. The stoppers are then placed in their respective bottles, well washed previously in distilled water, and the bottles and contents are allowed to stand for five minutes. They . are then well shaken for three or four minutes, till all the chloride precipitates. Some more distilled water is added till within two Tnches of the neck, and the contents allowed to stand for four hours. After this, the superfluous liquid is drawn off by a syphon, taking care not to draw up any chloride. More distilled water is added,, and, after two hours' rest, is drawn off THE PRACTICAL ASS AVER. as before, and sometimes a third and fourth washing is given. The bottles are then placed on their sides for half an hour, to enable the chloride to settle in one place. Meanwhile a pneumatic trough is prepared and filled with distilled water : corresponding to each bottle there is placed on the floor of the trough a small porcelain saucer with a porcelain cup each fiumbered correspondingly to the bottles. The stoppers are then removed from the bottles, and the operator places the forefinger of his hand over the mouth of the bottle, and inverts it oyer the appropriate cup, and almost down to the bottom. The contained chloride is allowed to fall into .the cup by its own weight. If this is neatly manipulated, none of the chloride falls into the saucer. The cups are carefully* lifted out and decanted almost dry : they are then gradually dried in a steam bath till the chloride forms a loose cake at the bottom of the cup. They are dried at a temperature of about 300 degrees (F.) for, more or less, two hours, when it is weighed. ASSAy OF SILVER. 89 If the operation has been skilfully conducted, the chloride exists in a firm, unbroken cake at the bottom of the cup, and can be easily lifted out by a pair of forceps. The only objection to this process is that if any gold exists in the sample assayed, it is not dissolved, and consequently gets thrown down with the chloride and is weighed and regarded as silver, which accident does not occur by the volumetric method. 18.825 grains of pure silver equal 25 grains of chloride. This weight, therefore, has become the standard weight for an assay. Instead, however, of having to be continually referring to tables, or calculating the proportion of alloy to pure silver, the idea was hit upon of stamping the weights, not with its actual weight, but with the actual value which such an amount of chloride would represent in pure silver. Thus, supposing the resulting chloride weighed 22.5 grains, which would represent 16.94 grains of pure silver, and consequently 900.00 fine, the weight would not have 22.5 marked on it, but 90 THE PRACTICAL ASS AVER. 900, SO that the assayer simply reads off the value at once. The whole process takes, more or less, twenty- four hours. Although this process seems pecu- liarly adapted to the Indian mint, still it is evi- dent that it is a much more tedious process than the volumetric method. Indeed, in the Indian mint it appears that the assays are not reported till the third day. It moreover appears that the gold, as before stated, is estimated as silver, which does not occur in the volumetric analysis. It is also evident that much more apparatus and manipulation is re- quired than in the first process. On the whole, it is difficult to see the advantage of the above method, BLOWPIPE ASSAY OF SILVER. This is probably the most useful assay that falls under the practical assayer's notice. Every student who wishes to get a clearer insight into the routine of blowpipe analysis is recommended to obtain Dr. Thompson's ASSAY OF SILVER. 91 " Guide to Mineral, Explorers," Plattner's work on the Blowpipe, and also the Numbers 380-84, 392-98, 412 of the Chemical News, containing the observations of David Forbes, F.R.S. A small portion of the substance to be assayed, varying in size according to the rich- ness of the sample, is to be carefully weighed on the blowpipe balance. This is to be mixed with some granulated lead and soda, and placed in a cavity of a sound piece of charcoal. The blowpipe flame is to be cautiously applied to the substance : after a bit the heat may be increased, and the substance finally fused into a globule of silver-lead, in precisely the same manner as in the crucible assay. It is advisable to take as large a portion as possible of the substance, in order to get more satisfactory results, and invariably to take two or three assays. The silver-lead thus obtained is then placed on a rather coarse cupel, bound round with a piece of iron wire to hold it by, and the cupel heated in the blowpipe flame, or on the hob 92 THE PRACTICAL ASS AVER. of a fire, to completely dry it. When thoroughly dry, direct the point of a good flame on to the lead, which is forthwith fused, and immediately commences to oxydize and rotate, the same as in a muffle. This oxydizing process must be kept up at the lowest temperature that will keep the lead fused, for reasons already explained. The globule must be kept in contact with the melted litharge. If the lead is rich in silver, very little rainbow colours play on the surface. If copper is present in the assay, the cupel will be black ; but if the ore is free from foreign metals, the characteristic lemon-yellow of lead appears. When the globule is reduced to about one-third of its size, or the dimension of No. 2 shot, it should be removed from the flame, taking care, as in the muffle assay, not to withdraw the assay too soon, but to cool it off gradually. A fresh piece of sound charcoal has a hole neatly scooped in the side, and a small quantity of very fine bone^ash, thoroughly dried, is pressed firmly into it with the iron or agate ASSAY OF SILVER. 93 pestle. It is carefully rounded off and smoothed down, and dried as usual in the blowpipe flame. The globule of silver-lead is then placed on it, and the point of the flame directed on to it for a moment to fuse it ; when well fused, draw the cupel away, and keep the point of the flame playing just on the edge of the bead or the bone-ash, but not touching Xki'e.h&sA, at an angle of 45 degrees. The flame must be hotter than in the preceding operation — hot enough to keep the litharge constantly absorbed, and to prevent it forming under the bead, which would cause the oxydation to stop. If the lead is retarded, as sometimes happens, by minute portions of the cupel or litharge sticking to it, the cupel must be inclined to one side, and the bead allowed to roll down to another place : a small fraction of lead facilitates this. When the brightening takes place, direct the point of- the blue flame on the bead for about ten seconds with a good strong blast, to detach any film of lead which might otherwise adhere to it, and cool gradually, to prevent spitting. By this means assays of 9+ THE PRACTICAL ASSAYER. silver may be made of the most surprising accuracy. Should the globule contain much copper, easily recognized by its colour, the bead will frequently come out flattened in shape. When copper is suspected to be in considerable quantities after the first cupellation, some more lead must be added to the globule, and the whole recupelled until the copper is forced off, as in a muffle assay. Of course the lead used must be quite pure from silver, and finely granulated. In this class of assay the loss in cupellation is less than in the muffle assay, and is not taken account of by the practical assayer for mercan- tile purposes ; consequently tables for correction are not added. The heat all through the operations should be kept as low as possible. In fact, in all silver assays, except scorification, the heat cannot be too low. Assays of the alloys of silver and copper can be made with equal exactness. The alloy may be submitted at once to the cupel ; but Mr. Forbes recom- ASSAY OF SILVER. 95 mends the addition of borax glass, about half the weight of the assay, and then fusing it on the charcoal in the reducing flame till it begins to rotate, and subsequently cupelling it, as described above. Generally speaking, lead equal to about the weight and a half of the alloy is sufficient, but if copper is present in considerable quantities, it is requisite to add from five to fifteen parts, according to the table given for silver alloys. The resulting button must be re-cupelled if suspected of con- taining copper ; but it is better to avoid this by employing a slight excess of lead, and finishing at once. If the button contains only a small quantity of copper, the assay may be finished at once, without previous concentration. ASSAY OF GOLD. The assay of gold ores is carried on in precisely the same method as that of silver ; it presents less difficulty in fact. It is highly essential that the ores should be thoroughly well ground up and got through an 80 sieve at least. Any flakes of gold that remain in the sieve must be carefully collected and assayed as alloys, and their value added to the amount of the sample, as will be explained. Of course, great care must be taken in getting a fair sample of the packet sent for assay, as,, otherwise, rock of a low percentage might easily escape detection. The furnace, crucibles, &c., are precisely the same as in silver assaying. In the assay of gold quartz, which will pro- bably be the mineral most presented to the operator's notice, it is usual to take 500 grains as the charge. The three following mixtures will be found ASSAV or GOLD. 97 efificient, according to circumstances and character of the ore : I. — Gold Ore 500 Red Lead . 500 Charcoal . . ,20 Carbonate . 600 2. — Gold Ore ■ 500 Red Lead . , 500 Borax . 150 Carbonate • 350 Charcoal . 20 3. — Gold Ore • 500 Red Lead . , 1000 Charcoal . 20 Carbonate . 100 Borax . , ■ SO The mixture must be intimately mixed in a good sized crucible, with the same precautions as in silver ores. Some assayers recommend a thick covering of salt on the top, but no advan- tage, accrues from this application. Give a good strong heat at the end of the operation, H 98 THE PRACTICAL ASSAYER. and pour- as usual. The slags in this class of assay are very thick, but they seldom retain any metal : if very viscid, a little more flux added by means of the copper scoop, and a five minutes' brisk heat, will generally render them sufficiently fluid. All gold ores, unless they are very rich, are much better assayed by this method than by scorification. In the scorification assay of rich gold ores, about ten parts of lead are sufficient, or 50 grains of the ore, and 450 of lead. Unless the sample is very rich, it is better to ta:ke four scorifiers, and afterwards scorify the four re- sulting buttons : the one resulting button can then be cupelled. The cupellatioh of gold buttons is very easy. It does not volatilize like silver, and conse- quently a greater heat can be maintained in the muffle than in the cupellation of silver. At the brightening, if the presence of copper is sus^ pected, a high degree of heat may be safely given; as copper has a very great affinity for gold. The accuracy of the cupellation can be ASSA y OF GOLD. 99 judged by the appearance of the assay, pre- cisely in the same manner as in silver cupel- lation. ALLOYS OF GOLD AND COPPER. Copper has a remarkable affinity for gold ; -much more so than for silver. We must, therefore, add a very considerably larger pro- portion of lead in the former class of assay than in the latter. Generally speaking,' this is about double. For instance, in an alloy containing 1^ of gold, about twelve or fifteen times the weight of the whole alloy would be required, and so on. The resulting button does not consist of pure gold, as it always contains a small per-centage of copper. It does no harm to re-cupel the button, as gold is never lost in the operatipn. In case of re-cupelling, about six times the amount of lead is all that is required. This "surcharge," however, is not reckoned in commercial assays. The presence of silver greatly facilitates the separation of gold from copper; when therefore silver is not THE PRACTICAL ASS AVER. already present in the alloy, a small quantity, say 2\ to I of gold, may be added to the assay. In order to find out the approximative value of the alloy, the touchstone may be .used, or a preparatory assay taken. The touchstone test, however, is fallacious, unless performed by a very practised operator, and, therefore, no de- scription is needed of the apparatus. It takes very little time to make a preliminary assay, thus : Cupel 5 grains of the alloy with about TOO of pure test lead, and note the result. Then, in the actual assay, add the proper pro- portion of lead and proceed as usual. ALLOYS OF GOLD AND SILVER. The operation of separating gold from silver is called " parting." It is performed as follows : Take the button which results from the cu- pellation (in the case of gold and silver ores), and, after correcting for the red lead, note the weight* on a delicate balance. This equals amount of gold and silver combined. Now take two and a-half parts, or a trifle less, of pure ASSAY OF GOLD. loi test silver, and wrap the gold button and the silver up in a piece of sheet lead. ~ Place a cupel in the muffle, and, when at a good heat, put in about six parts of test lead : when melted, drop in the sheet lead and contents, and cupel as usual. When cool, place the button between two pieces of paper, and flatten it by repeated blows with a hammer on an anvil. Clean it well, and then drop it in a parting flask. Now pour on it three or four spoonfuls of acid solution, composed of one part by measure of pure nitric acid and two and a half of pure distilled water, and allow to boil for fifteen minutes. Carefully decant, and wash once with warm distilled water. Then pour in rather more of an acid composed of half acid and half dis^ tilled water, and allow it to boil for twenty minutes, or rather longer. Now decant care- fully, as before, and wash the residue with warm distilled water. To get the piece or pieces of gold out of the flask, fill this latter up to the brim, and place a small clay or porcelain cruci- ble on the top, and press it down with the fore- THE PRACTICAL ASSAYER. finger ; take hold of the bulb of the flask, and suddenly turn it over topsy-turvy on the table.' The gold falls to the bottom of the crucible, and the flask can be lifted out very gently and slowly. If this is effected well, very little water comes out into the crucible. Decant off" any water that may be in the crucible, and gently dry off" the moisture. . When tolerably dry, place the crucible, with the gold in it, in a good hot muffle, and ignite it thoroughly. Now weigh it up, and the difference is the amount of silver in the ore or alloy. Sometimes the gold button bumps in the flasks. To aVt)id this, do not use pieces of char- coal, as nitrous acid is thereby generated, unless the charcoal is very pure and well burnt. Use in preference small clay balls of the size of a pea : one in each flask suffices. Suppose the operator has a piece of alloy to assay, quality and contents unknown ; proceed as follows : Weigh off 12 grains on the assay balance most carefully; Cupel this piece with about 300 grains of laad. Mark result ; correct for ASSAY OF GOLD. 103 the lead; th^ result = fine gold and silver, and the difference some base metal. Say the dif- ference is 3 grains. Note this down in your note-book. Now add two and a quarter parts of pure silver; cupel as described above, with about 200 grains of lead, and, the resulting but- ton is flattened out and dissolved as usual. Note the weight, say 6 grains, and the amount of silver is determined. The assay stands thus : Base metal . 3 grams Gold . . 6 „ Silver • 3 .. 12 grains in all ; or, as the 1 2 grains taken represent a troy pound, and as a troy pound contains 12 oz., the report is sent in' as follows: Base metal . 3 oz. in the pound troy. Gold . . 6 „ „ ,, Silver . • 3 » » •> 12 oz. Those assays are called "parting" assays 104 THE PRACTICAL ASS AVER. when the amount of fine gold and fine silver is wanted. Gold bullion can be assayed with different weights, and reported as so many carats, as follows : Weigh off a quantity of the gold to be esti- mated, equal to the weight representing 24 carats. Take 25 grains of pure silver, and cupel the whole with about 250 grains of pure lead. Dissolve in the acid solutions as usual, and weigh the resulting gold. Place the 22-carat weight in the balance, and place the gold in the opposite pan of the balance. If the gold is standard, they ought exactly to counter- balance : if it only weighs 2 1 carats, however, it is "one carat worse;" and if it weighs 23 carats, it is " one carat better." In parting assays, not more than two and a half parts of silver should be added to the alloyed previous to submitting the quartated button to the acid solutions. If three parts are added, the gold is obtained in the form of a fine powder, much more difficult to weigh up than a ASSAy OF GOLD. 105 single piece of gold. As a general rule, about two or two and a quarter parts are sufficient for general purposes. Supposing that, after assaying silver or gold ores, we either get silver poor in gold, or gold rich in silver, or, in other words,, where the silver far exceeds the limit of quartation, the button must be flattened out as usual, and dis- solved in nitric acid. The gold will remain under the form of a brownish powder, Tvhich can be dried immediately, or cupelled with a little lead in a cupel. If the quantity is very small, we can take the powder and dissolve it in aqua regia. Should gold be present, the liquid is tinged a yellow colour; if a drop of solution of chloride of tin is added, a violet hue is produced. Most minute traces of gold can be detected by this means. The blowpipe assay of gold is conducted in the same manner as that of silver ; but as these two metals cannot be separated by any means before the blowpipe, the button obtained must be parted by the wet process as usuah ASSAY OF TIN. This substance is always met with under the form of oxyde, or in alloys." The only method of assaying tin ore is by the dry process. Many wet methods by volumetric analysis have been proposed, but as no known acid or acids will dissolve oxyde of tin, they are all fallacious. The oxyde may possibly be dis- solved after previous fusion with potash, but this is only a clumsy expedient. All wet methods will therefore be omitted. /^zrsi Method. — Grind up the tin ore very carefully in an iron mortar, and get it through an 80 sieve. As this is exceedingly laborious work, it is as well to do it by proxy. After grinding and sieving, mix it up well in the mortar for five or ten minutes, till the powder no longer ap- pears veiny, but homogeneous. Half the dis- crepancies in tin assays arise from bad sampling. Always take two assays of the same sample. Take 1000 grains of the well mixed ore; ASSAY OF TIN. 107 van it to remove as much silica as possible, and place it in a large blue-pot crucible with 200 grains of anthracite coal, not too fine, about through a 40 sieve. Mix the contents up well, and powder over the top with a layer of anthracite. Place the blue-pot and contents at a strong white heat for twenty minutes in the reducing furnace. Lift the pot out, and scrape down the sides with the charred end of a stick till it is quite clean. Put it in the fur- nace again, and give it the very strongest heat possible for a quarter of an hour. Lift out the pot, and pour into a mould as quickly as possible. Allow the pot to cool, and scrape out the residue with a knife into an iron mortar. Wash off as much as possible of the charcoal slags, &c., and run down the remainder in a common Cornish crucible with carbonate of soda. Pour as usual, and add the result to the first ingot. In this operation great care must be taken to grind the ore fine, to have your furnace at a white-heat, and to pour carefully the first time. The best io8 THE PRACTICAL ASS AVER. way to effect this latter operation is to push back the slags, &c., from the molten metal in the crucible with a piece of stick, and to place the mould across the mouth of a large iron mor- tar, and then pour out as much as possible. All that does not go into the mould drops into the mortar. This method gives fair results ; but its great objection is that it requires such a high heat, which the explorer cannot often obtain. Second Method. — Take lOO grains of the fine-powdered ore, and 200 grains of coarsely pounded common cyanide of potassium, and mix up in a small Cornish crucible, together with 25 grains of charcoal. Powder over the top with another 50 or 60 grains of potassium, and place the crucible in the reducing furnace for twenty- five minutes, at a low heat — only just sufficient to keep the cyanide fused. Cover over the top with a piece of broken pot. Give a minute's slight increase of heat at the finish, and pour into a mould. The results by this method are exceedingly correct. This method possesses the great advantage of not requiring a higher ASSA Y OF TIN. 109 heat than an ordinary kitchen fire. Some precautions, howevers must be taken when pursuing this method of assaying tin. The best place to put the crucible is on the top of the furnace, with the top bricks open, much the same as in roasting operations, and the great point is to keep the top of the pot as hot as the bottom, so as to let the fused cyanide run down well, and not adhere to the sides. The piece of broken pot is to keep the top of the crucible and the contents as hot as the bottom, by confining the heat as much as pos- sible. The object being to keep the cyanide in the pot, and not to volatilize it, if dense white fumes come off, the furnace is too hot, and the crucible must be immediately removed. Domeyko proposes the following method : Treat 100 grains of the mineral with aqua regia, and after washing and calcining the resi^ due, it is mixed with 20 grains of charcoal of white sugar, and covered over with 100 grains of the same charcoal. The mixture is placed in a small porcelain crucible for a quarter of an THE PRACTICAL ASS AVER. hour, in a good muffle furnace : the crucible is then taken out, and the residue treated again with aqua regia, and the tin precipitated from the solution by pure zinc. Domeyko also recommends the use of cyan- ide of potassium as follows : Take 20.0 grains of the ore, and treat it as above described, as far as heating it in a muffle furnace. Then, instead of taking out this cru- cible and treating the residue with aqua regia, 300 grains of cyanide are introduced into the crucible, and the whole heated for five or ten minutes at a cherry-red heat. ALLOYS OF TIN. Iron, tungsten, &c., are usually reduced with the tin, and sometimes it is advisable to ascer- tain the proportion of these metals. If the ingot is malleable, it is reduced to thin leaves, or if it is brittle it is pounded up as fine as possible in an iron mortar. It is afterwards boiled with pure concentrated muriatic acid until the residue ceases to be attacked. The solution contains ASSAY OF TIN. tin and iron. The tin is then precipitated by sulphuretted hydrogen gas. The deposit is col- lected and treated with nitric acid : it is then evaporated to dryness, and the residue calcined into deutoxyde of tin. The solution or filtrate containing the iron is then boiled with nitric acid, in order to peroxydize the iron, and the peroxyde is precipitated by carbonate of am- monia. The residue of the alloy which has not been dissolved in muriatic acid is tungsten, with only a trace of iron. When the exact amount of iron, however, is required, the tungsten can be heated with twice its weight of saltpetre in a silver crucible, and afterwards washed with water : the tungsten, dissolves, and only pure oxyde of iron is left. When there is much iron in an alloy, it is less attackable by muriatic acid than when there is a large excess of tin. In this case it is better to fuse the alloy with a known quantity of pure tin, and commence as before. If not, the alloy must be boiled for some hours, during which some tungsten is oxydized,.which will give a dark-blue THE PRACTICAL ASS AVER. colour to the solution. If we suspect zinc is alloyed with the tin, it is easy to determine the quantity by dissolving the alloy in pure nitric acid, in which only the zinc is dissolved, while the tin remains in the residue in the state of oxyde. The solution is evaporated to dryness, and the residue calcined. at a red heat, to trans- form the nitrate of zinc into oxyde. When we have an alljpy of copper and tin, it must be dissolved in aqua regia, adding water and an excess of ammonia. The precipitate is filtered, and washed with ammonia diluted largely until the filtered water ceases to assume a blue tinge. The solution is boiled to expel the ammonia, and the liquor saturated with muriatic or sul- phuric acid, and the copper precipitated by iron in the usual way. The only difficulty which occurs in this case is that in the filtration of the ammoniacal liquor, small white particles of oxyde of tin pass through the filter.. But this may be a\'oided by adding two or three grains of lead to the solution before 'the addition of the ammonia. ASSAY OF TIN. 113 Tin may contain copper, lead, iron, and ar- senic. To determine the lead and copper, the piece of tin must be flattened out, and treated with nitric acid at boiling point," until it is com- pletely oxydized. The liquor is evaporated to dryness, filtered, and the residue calcined. If this residue is white, it consists of pure tin ; but if iron is present, the residue is tinged more or less yellow. The nitric solutions are evapo- rated to dryness in rotation, and the residue calcined in a platinum crucible : this residue is again dissolved in pure nitric acid. The lead is precipitated from the solution by sulphuric acid, and afterwards the copper by a plate of iron. To determine the quantity of iron and arsenic, another portion of tin is dissolved in muriatic acid, and the operation proceeded with as before. When the tin does not contain lead, we can attack it by concentrated muriatic acid, to dis- solve the tin and iron ; but it is necessary to stop the action of the acid before all the assay piece is dissolved, or otherwise the copper 114 THE PRACTICAL ASS AVER. would be dissolved at the same time. The residue is well washed, and treated with nitric acid, &c. The copper and the iron can thus be determined at one and the same time, ASSAY OF TIN BY THE BLOWPIPE. Galin's well-known method, by which the most minute traces of tin can be discovered, is as follows : A small portion of the mineral is slightly mois- tened and mixed with anhydrous carbonate of soda : it is then placed in a cavity in a sound piece of charcoal, and exposed to a good hot reducing flame ; some more soda is added, and the flame again applied. As long as any of the substance remains on the charcoal soda is added, until all the mass is absorbed and reduced. Extinguish the burning charcoal with a drop of water, and cut out the assay piece and sur- rounding part ; grind it up fine in an agate mor- tar. Grind and work alternately until all the charcoal, &c., is worked away. If any reducible substance is present, it will be found at the bot- ASSAY OF TIN. nS torn of the water ; if it is malleable, it will be in the form of lamina, and if brittle, in the shape of fine powder. By this means may be dis- covered half per cent, of tin. It must be ob- served that a good hot flame must be kept up, and all the assay covered by it. Very accurate results may be obtained as follows : Mix one part of the mineral with three or four parts of carbonate of soda, and place on the top of it a piece of cyanide of potassium the size of a pea after the mixture has been previously heated. Now apply a good strong reducing heat as before, and a globule of tin will be ob- tained. It is necessary for the practical assayer, and more especially for the explorer, to be able to judge of the purity of the tin, whether obtained by assay or by smelting. There are two methods of doing this. First. — By the noise which the ingot gives when bent, which is louder in proportion to the purity of the metal. ii6 THE PRACTICAL ASSAYER. Second. — By the appearance of the ingot when it sets. The tin to be tested must be melted in a crucible at the lowest temperature sufficient to effect it. Take the crucible out of the furnace, and clean off the oxydizing surface with a piece of stick, and wait till the surface presents a peculiar yellowish film. Now pour the /tin into a dolomite mould, in a room per- fectly quiet, and free from shaking. When it sets, observe the colour and the indications more or less of crystallization. The whiter the metal, and the less signs there are of crystallization, the purer the tin is. A good ingot of tin sets quite smooth, white, and with a slight longitu- dinal furrow dqwn the centre, like an ingot of copper ; but if the tin is impure, the surface is covered here and there with stars and spikes, and these are in greater or less abundance ac- cording to the purity or impurity of the metal. ASSAY OF LEAD. By far the most general ore of lead that comes under the assayer's notice is galena. Lead ores are always assayed by the dry method. Several wet methods are given in hand-books, but they are all objectionable, and consequently no notice is taken of them. There are two methods of assaying lead ores ; first, by using ah iron pot ; and, secondly, by using an earthern crucible and introducing iron in the assay. The first method is that usually practised and recommended at the School of Mines, and is the best method of assaying lead ores. These pots must be of the ordinary cylin- drical shape, and welded solidly together, not merely brazed. They will last, with care, for fifteen to twenty assays. The ore must be got through a 60 sieve, and, as in the case of tin ore, carefully mixed up to secure a homogeneous , sample, which very often causes great errors. 1 1 8 THE PR A CTICAL ASS A YER. w ^ The following mixture can then be mixed up in a sheet of glazed paper : Ore . . . 400 Carbonate . . 400 Borax . . . 100 Argol . . . 30 reserving most of the borax, and 100 grains of the carbonate of soda, to cover with. The crucible is heated to just a glow in the furnace, and then the mixture is projected carefully in. The crucible is placed at a low heat at first, and gradually raised to an ordinary tempe- rature, and the furnace top is closed. When the flux flows freely and smoothly, give a minute's high heat, and then pour into a warmed mould. The object of the final heating is to cause all the lead to flow to the bottom together ; but after this object is attained, the contents must not be poured if the crucible is very hot, but allowed to cool for a few seconds ; if poured when very hot, a thin coating of lead attaches itself to the iron crucible. If this occurs, a small quantity of flux must be added, ASSAY OF LEAD. 119 and the residue poured in again. The slags are detached as usual, and the button weighed. If carefully conducted, less lead is lost in this operation than in any other. Second method : This is performed in the ordinary clay crucibles, with the addition of fluxes and metallic iron. The same amount of ore, fluxes, &c., are to be taken, the contents covered over, and three pieces of hoop iron, or large nails (hoop iron is best), are pushed down to the bottom of the crucible. The crucible is then submitted to the furnace with all the pre- cautions already described ; but in this assay the time required is longer than in the former one, being about twenty-five minutes. Before throwing away the pieces of iron, they must be examined to see if any buttons of le^d still adhere to them, and, if so, they must be dipped and washed in the bath of lead till they are all detached. Examine the crucible for shots of lead, if necessary adding a little flux. In the assay of carbonates the same charge is taken, and iron can be advantageously used. THE PRACTICAL ASS AVER. Indeed, the above No. i method can be applied to almost all classes of lead ores. The following method is the one recom- mended by Mitchell, and is perhaps as good as any : Grind up 200 grains of the galena, and get it through a 40 sieve. Mix this with 50 grains of argol and 200 grains of carbonate of soda, and place the whole in a crucible which has been well smeared over with com- mon black-lead. Then insert three large nails (hoop iron is much better), and cover over the top with 200 grains of common salt, and over that 200 grains of anhydrous borax. Place them in the furnace, and raise the heat rapidly to a bright red ; then take off the cover of the furnace for eight or ten minutes. Cover the furnace up again, and raise the heat again to a bright red : when the flux flows smoothly, pour as usual, after washing the pieces of iron. The only corrections to be made are not to rapidly raise the heat, and not entirely remove the cover of the furnace. Care should be taken also to keep the top of the crucible as hot as ASSAy OF LEAD. 121 the rest of the contents, by packing the coke around it, as in roasting operations. By the above method, carefully performed, equally good results may be got as by any other. When galena contains silver or gold, both these metals pass into the lead entirely, and the contents must, of course, be certified for, as, whether the ore is assayed for silver or for lead, the assay, with only some small modifi- cations, is the same. If copper is present, some goes into the lead, and some into the slag. These buttons are harder than pure lead. Antimony renders the buttons brittle and granular ; they also are harder and more silvery in their appearance. Litharge and red-lead may be assayed, of course, by the simple addition of a reducing agent and a little flux. Thus, take 400 grains of litharge 200 „ argol, or 25 „ charcoal 400 „ carbonate ICO ,, borax. 122 THE PRACTICAL ASSAYEK. Fuse at the lowest possible temperature, and, after a minute's bright heat, pour as usual. When the red-lead is required to be assayed for silver also, take looo grains, and a corre- sponding amount of flux, &c., and reserve the button for cupellation. The surest way to obtain proof lead for silver assaying is to decompose the best white- lead obtainable, by means of charcoal. ASSAY OF IRON. The estimation of iron by the dry way has been omitted, as also the complete analysis of iron ores and steel. The assay of iron by the dry way requires a greater heat than is usually at the service, of the ordinary explorter, while the practical assayer is rarely called upon for a complete analysis of iron, as this belongs more to the province of the skilled metallurgist. I shall, therefore, only describe as plainly as pos- sible the process known as Dr. Penny's — ^the bichromate of potash method — which, for accu- racy, simplicity, and quickness, leaves nothing to be desired. MKTHOD OF ASSAY. Take from 305 to 307 grains of pure bichro- mate of potash, and dissolve them in four pints of distilled water, in an ordinary ammonia bottle. This forms the standard solution. 124 THE PRACTICAL ASSAYER. Take lo grains of pure, cleaned, harpsichord wire, and dissolve it in pure dilute hydrochloric acid ; or, better still, take three or four pieces of wire at hap-hazard, of about 3, 5, 7, 9 grains each, weighed on a most accurate balance, and dissolve them as before. Next take 3 or 4 grains of red prussiate of potash, and dis- solve them in at least half a pint of distilled water. This forms the test solution. All else that is required is an ordinary burette, and a white porcelain slab, about six inches square, placed on the operator's right hand. Take 10 grains of the ore to be assayed, if rich ; 20 grains, if poor. Put them into a boil- ing-flask with a small funnel in the neck, and boil with strong hydrochloric acid till all is quite dissolved. Now shake up your bottle of standard solu- tion, and fill up, as usual, a 1000 grain burette with it. Transfer the solution of the pure wire to a large porcelain dish of, at least, one pint capacity ; add water, and, having set your bu- rette at the proper mark, place the dish and ASSAY OF IRON. 125 contents under it. Now run in a few divisions of the standard solution, stir up with ^ glass rod, and occasionally test it as follows : Dip a glass rod into the test solution, and make seven or eight small drops on the porcelain slab with the adhering liquor. [N.B. — The slab must be perfectly clean and dry .J Wipe the glass rod again, and now and then take up a drop with it from the porcelain basin, and let it mix with one of the drops of the test solution on the slab. When not the smallest trace of blue colour ap- pears on the union of the two liquids, the assay is finished. Read off the number required to effect this, and that is the standard of your solution, precisely the same as in a copper volumetric assay. Say it is 9*65. Now trans- fer the contents of the flask containing the dissolved ore into a large pint flask; add distilled water, and then about 30 grains of sulphite of soda in crystals. The solution is gradually and gently heated till it is quite colourless, and then it is well boiled, to expel the sulphurous fumes. When the assay is com- 126 THE PRACTICAL ASS AVER. menced the solution must be quite colourless. If oxydization sets in, you must add more sul- phite of soda and commence again : if care, however, is taken to manipulate pretty quickly, this accident will not occur. The solution must now be transferred to a similar porcelain dish as in the case of the pure wire, and the standard solution run in as before described. If the solution appears of a red or orange colour after you have got it into the basin, add a little hydrochloric acid. Sometimes it appears of a dirty-green colour, in which case also excess of hydrochloric acid must be added. Read off the number of divisions on your burette required to effect the completion of the assay. Suppose 400 grains were required for the completion of the process, and 9"65 has been found as the standard, then we can calcu- late the percentage of iron in the ore, precisely the same as in a copper assay, by a simple pro- portion sum. ASSAY OF IRON. 127 At first it is rather difficult to exactly see the last few tints on the porcelain slab ; but after a little practice the necessary quick-sightedness is soon gained. ASSAY OF ZINC. The old method was by determining the amount of zinc by difference, or by volatilizing the metal or ore at a high temperature, and calculating the loss. The only process, how- ever, that will be mentioned here is that de- scribed in Vol. I. of Percy's " Metallurgy." When a solution of sulphide of sodium is addqd to an ammoniacal solution of zinc con- taining a small quantity of hydrated oxyde of iron, the zinc is thrown down as white sulphide of zinc, and the suspended oxyde of iron subse- quently becomes black by the excess of sul- phide of sodium which has been used in the operation. If, therefore, we know how much pure zinc is precipitated by a standard solution of sulphide of sodium, we can, of course, easily calculate the amount of zinc in an ore sent for estimation, as in a copper volumetric assay. The two solutions of sesquichloride of iron ASS A V OF ZINC. 129 and sulphide of sodium are prepared as fol- lows : I. Dissolve 50 grains of haematite in hydro- , chloric acid, or 35 grains of harpsichord wire in nitrohydrochloric acid, and dilute to i pint with distilled water. 2. Take 1400 grains of crystallized monosulphide of sodium, and dis- solve them in 4 pints, or 35,000 grains,, of pure distilled water. The solution should be clear and colourless, and if any black precipitate appears it must be filtered or carefully decanted off. It should be kept in glass bottles free from lead. This solution is liable to a slow decom- position, so that it requires to be restandardized about every fourth day. If crystallized sul- piride of sodium is difficult to be obtained, take 2000 grains of caustic soda, and dissolve them in i pint of distilled water. Pour off half a pint into a beaker, and completely saturate it with sulphuretted hydrogen gas. Then add it to the other half pint, and the standard approximately found ; afterwards dilute with water till it is of the proper strength K I30 THE PRACTICAL ASS AVER. Standardize your solution by weighing off exactly lo grains of pure zinc, or by taking pieces ranging from 5 to lo grains apiece at hap-hazard, andtaking the mean. Note the standard as in a copper assay. Take 10 grains of the ore if rich, and 50 if poor ; put them into a flask, and treat with nitrohydrochloric acid, using a small quantity only. When the ore is completely decomposed, a little water is added : ammonia and carbon- ate of ammonia in excess are added, and the solution is heated gently for twenty or thirty minutes. It is now to be filtered into a pint flask, and the residue on the filter well washed with ammoniacal water. To the filtrate add 50 grains by measure of the sesquichloride of iron diluted with ammonia. Allow it to get quite cold, and then run in the sulphide of sodium solution, continually shaking the flask containing the solution of zinc. When the precipitate assumes a greyish black colour, the assay is finished. Read off" the number of divisions on your burette that has been required ASSAY OF- ZINC. I3r to effect this, and the per-centage of the ore is easily calculated. There is a slight error, owing to the fact that a small quantity of zinc remains in the residue after the digestion in ammonia and car- bonate ; but this is balanced by the fact that a slight excess of sulphide of sodium solution is used to blacken the oxyde at the end of the operation. Say we have taken 25 grains of the ore; then we have 1000 grains, or 100 divisions, of standard solution (= 10 grains of pure zinc), and as 25 grains of the ore have required 60 divisions (on ai burette marked in 100 divi- sions) ; we have the sum as in a copper assay, thus : 100 : 60 : : 10 in 25 grains, or 24'o per cent. The liquid must be continually agitated during the process, or otherwise the sulphide of sodium might come in contact with the oxyde of iron and blacken it before the whole of the 13Z THE PRACTICAL ASSAYER. zinc is precipitated. Towards the end of the operation, of course the sodium must be gra- dually added, when the oxyde changes from a mahogany colourto blackish. If a great deal of iron is present when the ammonia is added, it is better to decant off carefully the liquor, and then treat the assay again with ammonia as before ; then filter again. Manganese, as in a copper assay, may be partly got rid of by carbonate of ammonia ; but a little bromine dropped from a glass rod into the ammoniacal solution will entirely re- move it. Copper can be separated by precipitating it on iron wire, as in a copper assay, after dissolv- ing the ore in. sulphuric acid. Nitric acid is now added to peroxydize the iron, and then the assay is gone on with as before. Before the blowpipe blende gives off a strong, intense light, but is infusible : it is of a waxy appearance. Carbonate of zinc is also infusible. When ASSAY OF ZINC. 133 heated on charcoal it turns yellow ; on cooling it becomes white. Silicate of lead is infusible : it gives out a green light. A SSA Y OF ME R CUR Y. Cinnabar is the ore that nearly always comes under the assay er's notice. Its appearance is well known. Mercurial ores are always esti- mated by distillation. About 500 grains of the ore is taken and placed in an iron or earthen- ware retort, and the contents distilled over and collected in a flask kept cool by water. If only a small quantity, as 100 grains, are assayed, the most convenient plan is to use a tube over a bath of hot charcoal of the usual well-known shape. The top of the tube must be kept hot, to prevent any mercury adhering to it. The mercury can be collected in a basin of water, dri^d, and weighed. Graham, in his " Elejnents of Chemistry," gives the following method : " To separate it from its compounds in the metallic state, it may be distilled with quick- lime in a tube of glass. Into this tube is intro- duced, first of all, a column of carbonate of lime about an inch long, then the mixture of the sub- ASSAY OF MERCURY. 13S Stance with quicklime, then another layer of quicklime two inches long, and then a plug of asbestos to keep the lime in its place. The open end of the tube is drawn out, and bent at an obtuse angle. The tube is now laid in a combustion furnace, the neck being turned downwards and made to pass into a narrow- mouthed bottle containing water, so as to termi- nate just above the surface of the water. The tube is gradually heated by laying pieces of hot charcoal round it, beginning at the part near the neck containing the pure quick- lime. This portion having been brought to a good red-heat, the fire is carefully extended to the middle part, to decompose the compound and volatilize the mercury : any portion of the compound that volatilizes undecomposed will become decomposed in passing -over the red- hot lime at the end. Lastly, the back part of the tube containing the carbonate of limeis heated, so as to evolve carbonic acid gas, and sweep out all the mercury vapour contained in the tube. The quantity of gas thus evolved ma/ 136 THE PRACTICAL ASSAYER. be increased by mixing carbonate of soda with the carbonate of Hme. The mercury condenses in the bottle, which must be kept cold. The water is poured off as quickly as possilale, and the mercury transferred to a porcelain crucible, dried in blotting paper and weighed." The Chemical News describes the following most elegant method for the assay of- mercurial ores, and which furthermore possesses the ad- vantage of being accurate : If the ore is about i per cent., take lo grammes. • „ is up to lo „ „ 5 „ over 30 „ „ I gramme. Mix with half their weight of iron filings, and cover the mixture with rather more than a quarter of an inch of clean iron filings. A porcelain crucible has its edges ground per- fectly flat, and a gold cup, about two inches across, and of a deep shape, in weight, more or less, 250 grains, is made to fit the crucible most accurately three-fourths of the way up. ASS A V OF MERCVR Y. 1 37 Place the ore in the crucible, and then fit the gold cup on the top, and fill the concavity with water kept cold. The gold cup must have been previously accurately weighed. Heat the cru- cible for ten minutes or so over a Bunsen's burner or Argand spirit lamp, and the mercury deposits itself on the gold. The gold cup is then removifed, and the mercury washed with alcohol from a wash-bottle. After being allowed to cool, and dried, the increase of weight gives the per-centage. The mercury can be removed by gently heating it over a spirit lamp where there is a good draught. In this assay the cover must fit closely, to avoid loss of mercury by volatilization, and must be deep enough to hold a considerable quantity of water to keep it cool, although small pieces of ice might effect this if at hand. The iron filings must be clean. When assaying rich ores, the alcohol used for washing must be collected, and any minute traces of mercury collected by pouring it into the cup of gold, which will take up any that remains. 138 THE PRACTICAL ASS AVER. Before the blowpipe cinnabar volatilizes, and gives off a smell of sulphur. If a small piece is mixed with a little carbonate of soda, and placed in an iron spoon, and heated over a spirit lamp, the volatilized mercury may be col- lected on a sovereign or small plate of gold held about half an inch above it. Weigh the plate, and the difference gives the per-centage. This is an exceedingly accurate test for mercury. If an ore is suspected to contain native mer- cury, it . may be discovered by simply heating the mineral in an iron spoon by itself and col- lecting on a gold plate as before. Assays of mercury in a small way maybe very conveniently performed as follows : , 1. Mix a small quantity of the material with iron filings pr metallic tin, and heat the mix- ture in a close tube to a bright red. The mer- cury sublimes, and collects, in the coldest part of the tube, like a metallic dew. Collect the globules with a perfectly dry feather. ; 2. A still better method is to take a closed tube of about seven or eight inches long: bfend- ASSAY OF MERCURY. 139 round the dosed end like a small retort : this bent part should be about two inches long. Dry the tube well over a spirit lamp, and intro- duce lo grains of the powdered niaterial, with about two parts, or rather less, of Jitharge. Heat the curved part slowly at first, but gradually increase the heat until the material is fused completely. The water which is formed condenses and goes out at the open extremity of the tube, while the mercury forms like a dew, and sometimes like a barely perceptible cloud, at the point where the tube begins to curve. Then, in' order to collect the mercury, the curved part is intro- duced a little further into the fire, so that the small drops of mercury -vsrhich are dis- seminated through the tube may unite nearer the orifice, and form a ring, which ring can be driven as • far as convenient from the curved part by means of the hot flame of a spirit lamp. Then cut off the glass near the ring of mercury, and collect the mercury with the dried feathers of a pen ; let the drops fall 140 THE PRACTICAL ASSAYER. into a capsule of water, and heat for a moment to unite them into one button, and then 'weigh. This method of assay is most exceedingly exact, and is especially adapted to arsenical ores. The tube must be bent, as otherwise the water which is evolved would be continually flowing back to the bottom, where the tube is hottest, and would consequently break the glass, or, by spitting, cause loss of the material under assay. 3. Place about one grain of the material on a sovereign, and add a drop of muriatic acid : drop in the acid a morsel of tin. If mercury is present, an amalgam is formed immediately on the sovereign. Wash off the acid, tin, -&c., and a metallic white spot appears where the tin was. ASSA Y OF MANGANESE. The value of the ores of manganese entirely depends on their relative power of evolving chlorine. The amount also of some foreign bodies, notably protoxyde of iron, should also be estimated, as these diminish the value of the ore. Many methods have been proposed for the assay of manganese ore. Fig. I. — Will and Freseniiis's apparatus. I, Method of Will and Fresenius. — This well-known method consists in taking 50 grains 142 THE PRACTICAL ASSAYER. of the ore to be examined, and introducing it into the flask A of the figure i, together with 1 50 grains of neutral oxalate of potash, which may be easily prepared by saturating oxalate of potash with carbonate of potash, and evaporat- ing to crystals. Concentrated sulphuric acid is then poured into flask B of the same apparatus till it is about one-third full. Now cork up the two flasks with the connecting rods, and weigh the whole accurately. Plug up, the opening b, and suck up a little air from d. A vacuum is caused in A, and a little sulphuric acid passes from B into A. The oxygen which is con- tained in the manganese will react upon the oxalic acid, which will generate carbonic acid. This carbonic acid passes into the flask B, is deprived of its moisture by the sulphuric acid, and escapes out at d. The same process must be gone through again and again till no more gas is evolved. Now remove the plug at b, and Slick at d till no more taste of carbonic acid is noticed and the apparatus is filled with com- mon air. Wait till the flasks are quite cold,' ASSAY OF MANGANESE. 143 and then weigh ; the loss of weight represents the amount of pure peroxyde of manganese. The following was recommended by Dr, Thompson ; and, if tolerably carefully per- formed, gives pretty fair results: Take 50 grains of the mineral, finely ground, and place them in a small Bohemian glass flask with about i^ oz. of water and \ oz. of sul- phuric acid. Then in the neck insert a plug of cotton wool, to absorb the moisture of the car- bonic acid as it passes out. A tube with dried chloride of calcium may be used if preferred. Now weigh the flask and contents, and imme- diately afterwards introduce 100 grains of oxalic acid : replace the wool, and let the flask stand for some little time during effervescence. Then apply a very gentle heat till no more carbonic acid is evolved : allow the flask to get quite cold, and weigh. The loss of weight corre- sponds to the amount of peroxyde in the ore, Suppose it loses 30 grains (in 50 grains), then the per-centage is 60 per cent. The ordinary method for available amount of 144 THE PRACTICAL ASSAYER. manganese is that known by the name of Otto's process, which consists in combining the mineral with an iron salt, and then, by means of a bi- chromate standard solution, estimating the ex- cess of the iron ; thus reversing the order of the ordinary iron assay. Any known quantity of pure harpsichord wii'e is dissolved in pure dilute sulphuric acid (i of acid to 3 of distilled water) : 30 grains is a convenient amount. A flask is fitted up with a bent glass tube, so that the end dips into a small beaker containing a little water. The large flask containing the wire is heated till it is dissolved. Now intro- duce an equal amount of the ore to be esti- mated, replace the cork, and boil gently till the soluble part of the manganese is dissolved. The lamp being taken away, the water from" the small beaker is allowed to run back into the larger flask. The tube, beaker, &c., are well washed out, and water is added to the larger flask until it is about half full. The ex- cess of iron can now be estimated by a standard solution of bichromate. The difference h&- ASSA Y OF MANGANESE. 145 tween the amount indicated by the standard solution and the original amount taken, viz., 30 grains, gives, of course, the amount of iron that has been peroxydized by the manganese, and from these data- can be calculated the amount of peroxyde of manganese. For in- stance, supposing 30 grains originally taken. Then we have, say : 5^ grains of iron unoxydized 30 „ „ originally taken 25 „ „ remain oxydized. Now, 25 grains of iron are equal to 19 "2 3 grains of peroxyde of manganese : as we took 30 grains, we get, as the percentage, 64-10 of peroxyde in the ore. Any iron that passes over is arrested by the water, and, of course, is washed back into the larger flask. The standard solution is prepared in precisely the same manner as recommended under "Iron Assay," viz., looograins of bichro- mate = 10 grains of iron. If the ore contains more than 75 per cent, of L 146 THE PRACTICAL ASS AVER. peroxyde, either less ore or more pure iron must be used. Graham also gives the following method ot readily estimating the value of the bioxyde. Fig. 2. — Graham's method for estimation of manganese. Take a small flask of about 4 oz. capacity, fitted with a perforated cork. A tube, about 3 inches long, is drawn out at one end, and filled with pulverized chloride of calcium, to absorb moisture : it is passed through the perforated cork, and a small, short test-tube, small enough to go inside the flask, is filled with 100 grains of hydrochloric acid. Fifty grains of the finely powdered mineral are placed in the flask, together with about half an ounce of cold water. The tube with the acid is now intro- ASSA Y OF MANGANESE. 147 duced, and also 50 grains of crystallized oxalic acid. The chloride of calcium tube is fitted on, and the whole apparatus weighed directly. The flask is then inclined, so as to allow the acid to flow out of the tube and come into contact with the oxalic acid and manga- nese : a gentle heat is at the same time applied. Carbonic acid is evolved, and escapes through the calcium tube. To expel all the carbonic acid, the solution must be gradually heated to boiling point, after which it is allowed to get quite cool, and then weighed. The loss of weight gives the quantity of carbonic acid. Now, as 43 "6 7, the equivalent of bioxyde of manganese, is nearly double that of carbonic acid, which is 22, the loss of weight in the ap- paratus may be taken as equal to the quantity of real bioxyde in the 50 grains of the sample. This process, though not peculiarly exact, gives tolerably good results for approximate assays, and can be performed with the simplest apparatus, in a minute or two. ASSAY OF BISMUTH. This metal, which is becoming of such value, is well worthy of the assayer's and explorer's notice, if he is lucky enough to come across any deposits of it. Native bismuth, the sulphurets, oxydes, and carbonatfes can be assayed by an ordinary fliix and reducing agent. Thus, take : Ore loo Carbonate . . . .250 Argol or charcoal as usual. Or, Carbonate . . . .200 Borax ..... 100 Argol, or cyanide of potass . 100 Mix and cover in a crucible, and fuse with the ordiniary precautions. As, however, bis- muth is most exceedingly volatile, this must be effected at as low a temperature as possible. When, however, there is a great quantity of copper in the ore, the copper is reduced with ASSA y OF BISMUTH. 149 the bismuth, and must be separated. The ores of Bolivia and Northern Chile nearly always contain copper. Mr. Hugo Tamm, in No. 640 of the Che- mical News, has given the following method, for purifying bismuth from copper, arsenic, antimony, and sulphur. I. Copper. Eight parts of cyanide of potassium and three parts of flowers of sulphur are mixed together, and one part of this mixture is sprinkled over sixteen parts of the molten metal, at the lowest possible temperature. A reaction takes place, and the metal is brought to a red heat, and the sulpho-cyanide begins to burn vividly, throwing out blue scin- tillating sparks. The crucible is covered over, and great care must be taken not to let the heat get higher than the burning point of the sulpho-cyanide, because sulphuret of bismuth would commence to volatilize. After the contents, of the crucible have I so THE PR A CTICAL A SSA YER. settled and been well stirred with a clay stirrer, the metal is poured into a mould after the flux has set. 2. Antimony. . Calculate more or less, the amount of anti- mony there is in the alloy, and add about three times the amount of oxyde of bismuth. The oxyde of bismuth is instantaneously reduced to the metallic state, arid oxyde of antimony formed, which floats on the top, and can be easily removed. Of course, iron and carbon must be carefully excluded in this operation. 3. Arsenic and Sulphur are easily removed, by melting the metal under cover of a flux to prevent its volatilizing, and strips of iron are plunged into the molten metal. When no more iron is attacked, the crucible is lifted out and allowed to cool. The arseniuret of iron sets, and the molten bismuth underneath is then poured out into a mould. Pure bismuth fractures bright, and with a reddish colour. When arsenic is present, the fracture is more silvery, and presents the ASSAY OF BISMUTH. 151 appearance of fish-scales. Antimony forms minute crystals : sulphur imparts a blackish tinge. Antimony may be also detected by dissolving some of the metal in nitric acid. If a cloudy white precipitate forms, antimony is present ; but if a crystalline precipitate falls down, which dissob/^es in water, lead is present. Arsenic can be detected by heating a piece on charcoal in the oxydizing point of the blow- pipe flame. When bismuth ores contain a large amount of copper, whether in the shape of oxyde or pyrites, the complete separation of the two metals is most difficult. Mr. Tamm recom- mends his sulpho-carbon process, which de- pends on the fact that in the presence of alka- line fluxes sulphuret of bismuth is reduced, but not sulphuret of copper. When sulphuretted ores are under treat- ment, both the bismuth and copper being in the state of sulphurets, all we have to do is to run them down with some carbonate and salt. 152 THE PRACTICAL ASSAYER. with a little sulphur and carbon, to insure com- plete sulphurization of the copper. In case of the oxydes being assayed, we must employ more sulphur, as follows : Make up a flux composed of Carbonate soda . . .5 parts i>a,It ' . . . . . 2 „ Sulphur , . . . 2 „ Charcoal . . . . i „ and mix it with three parts of the ore. Iron stirrers must be avoided in this assay. When only a small quantity of copper exists in the ore, it is better to run it down with an ordinary flux, and purify the resulting metal after- wards as before described. Mr. Tamm says that in the sulpho-carbon process a loss of 8 per cent, of bismuth occurs, which, he adds, is unavoidable. Another method is as follows : Take 100 grains of ore, and treat with strong nitric acid, till the whole is dissolved : evapo- rate the contents to dryness, and add some ASSA y OF BISMVTH. 153 sulphuric acid : evaporate again to dryness, and then add a little acidulased water. Filter, and add carbonate of ammonia in excess. Filter, wash, and dry the precipitate ; ignite it in a porcelain crucible, and weigh : every 100 parts = 90 of bismuth (nearly). To this Graham adds, that if hydrochloric acid is present in the solution, the bismuth cannot be estimated by carbonate of ammonia directly, as oxy-chloric of bismuth would be thrown down with the precipitate. The bis- muth must be precipitated by hydrosulphuric acid, the sulphide of bismuth oxydized and dissolved by nitric acid, and then treated as before by carbonate of ammonia. Mr. W. Pearson has given the following process for assaying bismuth by volume : Dissolve 7135 grains of pure crystallized bichromate of potash in 100 grains of water. Prepare two more solutions, one a tenth part of the strength, and the other a hundredth part of the strength of the above, or, to 'put it in figures, '07135 and -007135 respectively. Of 154 THE PRACTICAL ASSAYER. course the quantities can be made larger if necessary. loo grains of the solution first described (7135) equals i grain of bismuth, and, conse- quently, 100 grains of the second and third equal "i of a grain and 'oi of a grain respectively. The calculation is evident. ASSAY OF NICKEL AND COBALT. This is one of the most useful, but, unfor- tunately, one of the most difficult assays that come under the assayer's notice. The recent discoveries of cobalt ores in South America and the Cape have rendered it necessary, however, that the explorer and practical assayer should know, at least, how to estimate the two toge- ther, if not able to accurately determine their respective values. The great difficulty consists in the separation of the nickel from the cobalt. The method known as Rose's method, given in the " Handbuch der Analyt. Chemie " (Berlin, 185 1), is as follows: It principally depends on the fact that protoxyde of cobalt in a solution is converted by chlorine into sesqui- oxyde ; but in the case of nickel this change does not take place. The oxydes are dissolved in hydrochloric acid, and the solution diluted with a large quantity of water — about ilb. cf water to every 20 grains of the oxydes. 1S6 THE PRACTICAL ASS AVER. Chlorine gas is then passed through the solu- tion, until in great excess. This must be con- tinued for some hours. Carbonate of baryta is then added in excess, and the whole left to stand for fifteen or eighteen hours, and occa- sionally shaken up. The precipitate, consisting of sesquioxyde of cobalt and carbonate of baryta, is collected on a filter and washed with cold water. The filtered liquor, which has a green colour, contains all the nickel without any cobalt. The precipitate is then boiled with hydrochloric acid, to convert the sesquioxyde into protoxyde. The baryta is then precipitated by sulphuric acid, and subsequently the cobalt from the filtrate by potash. The nickel from the previous solution must now be precipitated, also by potash, the baryta being removed by sulphuric acid. The great point is to give a very large excess of chlorine, and also to take care that all the sesquioxyde of cobalt is precipitated by the baryta. The liquor should not be filtered for at least eighteen hours. ASSAV OF NICKEL AND COBALT. 157 Domeyko recommends the following mode of separating these metals, which is the method of Forbes, slightly altered. Domeyko says that he has found it by far the most convenient and accurate of all the methods that he has tried, but he adds that he always begins by running down the mineral to be assayed first of all into a regulus, and then proceeding in the same manner as if the regulus was raw ore : 1. Fifty grammes of the mineral are mixed with 30 grammes of glass of borax and 3 grammes of charcoal. This mixture is intro- duced into a crucible, and covered over with dried salt, and run down. All the nickel, cobalt, - copper, and iron, will be found at the bottom with the arsenic, and the slag is free from nickel and cobalt. 2. Having determined the weight of the button, i^ grammes of the matter are taken, and calcined in a capsule in a muffle at a red heat. A Bunsen's burner serves the same purpose. Charcoal is added, and the heat kept up until the arsenic is dispelled. The residue is taken 158 THE PRACTICAL ASS AVER. and mixed with 5 grammes of carbonate of soda and 4*5 grammes of nitrate of potash, and run down in a silver crucible. 3. The mass is boiled in water, and the insoluble parts collected on a filter, which is washed with boiling water. This must now be dissolved in hydrochloric acid, adding a little nitric acid, and to the liquor thus obtained car- bonate of baryta is added. The solution is allowed to stand some time, and is not heated, but only shaken occasionally. The precipitate is hydrate of peroxyde of iron. 4. Filter the liquor, and add sulphuric acid to precipitate the excess of baryta, and soon after pass a current of sulphuretted hydrogen gas through the solution, by which the copper, lead, antimony, bismuth, and any remains of arsenic are precipitated in the form of sulphs. 5. Having separated these by filtering, the liquor must be neutralized by ammonia, by which the sulphs of cobalt, nickel, and manga- nese are precipitated. A little time after, before the solution is filtered, acetic acid is added ASSAy OF NICKEL AND COBALT. 159 until the solution acquires an acid reaction. This acid attacks only the sulphs of manga- nese, without touching the other two, which are collected on a filter, and washed with sulphu- retted hydrogen water. 6. Detach these sulphs from the filter, and dissolve them in muriatic acid, with which a few drops of nitric acid have been mixed. From this solution we precipitate the oxydes of cobalt and nickel by caustic potash, or, better still, by caustic soda, adding as little as pos- sible of these reagents. The precipitate thus formed must be well boiled, and carefully washed' by decantation, and finally collected on a filter. The washing must be continued till a drop of the water gives not the smallest sign of alcali when evaporated on a slip of glass. 7. If the resulting material was composed only of oxyde of cobalt or of oxyde of nickel, which very rarely happens, we should only have to calcine the residue at a very high tempe- rature, and calculate the cobalt or nickel by the weight of the protoxyde which is obtained. In i6o THE PRACTICAL ASS AVER. case of greater exactness being required, it would be necessary to reduce the oxyde by hydrogen and weigh the metal. 8. If we wish to separate the two, we must first dissolve the calcined oxydes in nitric acid. A small residue of silex may be observed, and must be allowed for. The two oxydes are now to be precipitated by potash, collected in a filter, and washed with boiling water. A solu- tion of pure cyanide of potassium must then be passed through the substance in the filter, and the liquor that passes through collected sepa- rately in a flask. The filter is washed with boiling water, until nothing remains* in the filter, and the solution boiled. As soon as it commences to boil, oxyde of mercury in very fine powder is introduced (especially prepared by levigation), without stopping the boiling. The precipitate which is formed, besides the excess of oxyde of mercury, contains all the nickel, while the cobalt remains dissolved. The solution is then filtered, the precipitate washed with hot water, and, after drying, calcined at a ASSAY OF NICKEL ANl? COBALT. i6i red heat. The oxyde and cyanide of mercury go off, and oxyde of nickel remains. The result is weighed, and the difference gives the amount of cobalt. The cyanide qf potassium must be pure, and if this is not the, case, it must be calcined with " the addition of ^ little charcoal, ^nd afterwards dissolved in water. The two following methods for the. assay of these metals are the ones best suited to the requirements of the explorer and practical assayer. First Method: Take 50 grains of the ore finely pounded and passed through an 80-mesh sieve, and calcine the ore in a clay ,crucible till it is quite " sweet" and free from sulphur. Not a trace of this sub- stance must be left in the ore. The calcined residue must now be mixed with an equal weight of metallic arsenic, and heated in a small French crucible for about ten or twelve minutes at a not very strong heat. A small round piece of clay is inserted half-way down M i62 THE PRACTICAL: ASSAYER. the tapering crucible to prevent the rapid disen- gagement of arsenical vapours. Detach the residue, and place it in a larger French cru- cible, and add the following mixture : Carbonate soda . . . 1 50 grains Borax . . . . 50 „ Tartar . . . • 50 „ Fuse the mixture at a low heat, and pour out as usual. Weigh the resulting speiss. If iron is not present in the ore, 5 grains or so of fine iron wire must be added, as an indispensable condition. Second Method: Pass the ore through an 80 sieve. Take 100 grains and dissolve them in nitro-hydro- chloric acid, Dilute the solution with distilled water, and filter. Sulphuretted hydrogen gas must now be passed through the liquid (Fig. i) until in great excess. Filter the liquid, using thd sulphuretted hydrogen water to wash the precipitate. Boil the filtrate, and peroxydize the solution with nitric acid. If the filtrate is not peroxydized, a drop of nitric acid will produce ASSAY OF NICKEL AND COBALT. 163 a dark colour; but this colour appears only instantaneously, and must be closely watched. Fig. I. — Apparatus for making and washing sulphuretted hydrogen gas. •Now add carbonate of baryta till the solution is alkaline ; boil the solution, filter and wash the precipitate. Dry the residue, and ignite in a crucible. This residue must now be fused into a speiss with its own weight of arsenic, as in the first operation. The speiss, however obtained, is to be weighed. If the button is not much larger than a good-sized pea, the whole may be taken for the next operation ; but if it is much larger, it had better be broken up and a weighed quantity taken. During all this time the smallest and strongest muffle that the operator can procure must have i64 THE PRACTICAL ASSAVER. been urged to its utmost heat. The back of the muffle must be difficult to see, on account of the high temperature. A quantity of little clay Front view. Side view. Fig. 2. — Clay cups. cups (Fig. 2) are taken, and two or three placed in the muffle to heat. A dish of coarsely pounded glass of borax is placed on a conve- nient table, and a washing-basin full of cold water on a stool by the side of the muffle. The operator proceeds as follows : Remove the door of the muffle, and place a little borax glass in one of the cups, and push it back to the far end of the muffle, and shut the door again. When the clay and borax are at the same heat as the furnace, wrap up the weighed piece of speiss in a piece of paper, and with the tongs drop it into the melted borax. The furnace should be hot enough to instantly ASSAY OF NICKEL AND COBALT. 165 melt the button, this being one of the indispens- able conditions of the assay. There must only be sufficient borax to allow the melted button to revolve in, and not enough to drown the button. The button immediately begins to rotate, like a silver-lead bead in a cupel, and after a few moments it must be seized with the tongs and drawn quickly out, and plunged, bead and all, as quickly as possible into the basin of water. When cold, examine the borax, and if iron is still coming off, only the characteristic tinge of iron will be observed ; but if the very smallest trace of cobalt has come off, the borax will be tinged blue. Directly this occurs, the operator knows that only cobalt, nickel, and perhaps copper, remain. Supposing that no blue tinge appears in the borax, a fresh little cup is placed at the back of the muffle, the button again dropped in and cooled as before, until the blue tinge appears. The operation is proceeded with till all the iron is gone, when the button is taken'and placed in a small cru- cible dnd covered over with charcoal ; it is 1 66 THE PRACTICAL ASS AVER. melted till no mo.re arsenic fumes are given off, and is then treated exactly as before, occasion- ally testing the button to see when the cobalt is exhausted. When this point is gained, the button will stop revolving for a time, and the operator must be on the watch for this sign. The cup is now drawn out again, cooled, and the borax examined for the characteristic red- dish-brown colour of nickel. Any copper which may be present will come off last. If carefully conducted, this process is by far the best for commercial purposes, and gives most exact results. The requisite heat is the only difficulty, but by adding some extra iron piping to the chimney of a Plumbago Crucible Com- pany's muffle furnace, placing some anthracite at the bottom of the fire, and carefully choosing the coke, a very high temperature may be got, as long as the muffle itself is a small one. The moulds can be turned for a few shillings. The estimation of the metals by this process is effected as follows : * Product, after the removal of the iron and ASSA Y OF NICKEL AND COBALT. 167 excess of arsenic = Ni* A s + Co* A s, in varying. proportions. Remove the Co* A s, and Ni* A s is left. But when the weight of each is known, it is easy to calculate the relative amounts of nickel and, cobalt. For instance, suppose the weight of the speiss of Ni* A s = Co* =20 grs., and the weight of the Ni* A s, after the removal of the Co* A s = 10. The amount of Co* A s = ID grains by difference. Then Ni*As Ni : 10 grs. : : „ 193 ^ \i% : X Answer = amount of nickel in weight of speiss (Ni* A s) which has been found from a grain weight of ore. C2IAI : 10 grs. :: ^^ 193 i\2> ■ : X Answer = amount of metallic cobalt in weight of speiss (Co* A s) which has been found in given weight of ore. As, however, cobalt is usually returned as protoxide, then we have — Co Co CoO 29-5 : found : : 37"5 : x Answer = weight of protoxyde of cobalt. 1 68 THE PRACTICAL ASS A YER. Domeyko recommends the following method for the assay of nickel and cobalt, as most likely to meet the requirements of the explorer and commercial assayer : Take 5 grammes of the mineral if it is rich, and 10 if it is poor. If its base effervesces with acids and the mineral is grey cobalt^ white cobalt, grey nickel, or kupfernickel, without much red or green colour about it, it must first be boiled with acetic acid, Run down the residue with two or three times its weight of saltpetre, and two or three parts of carbonate of soda in a silver crucible. After the crucible has cooled, it is placed in a large porce- lain dish, and boiling water is added, and the whole allowed to stand until the material is well detached from the crucible. The solution is filtered, and the residue washed with boiling water. This residue will contain all the iron, nickel, and cobalt. The filter is dried, and the material detached from the filter ; this latter is now carefully burnt, and the ashes added to the material already detached. This precipitate is ASSAV OF NICKEL AND COBALT. 169 now boiled with muriatic acid, and the solu- tion carefully evaporated to dryness. Add water, and filter. To the filtered liquor add powdered carbonate of baryta, taking care not to heat the liquor ; add the reagent until ircfn ceases to be precipitated, and the carbonate dissolved. Having separated insolubles by filtration, and well washed ihetti with cold water, nothing re- mains in the solution but nickel and cobalt with the baryta, from which they are easily separated by means of sulphuric acid.. Lastly, the oxydes of nickel and cobalt are precipitated by excess of caustic potash, heating the liquor to boiling point, and washing the pre- cipitate with boiling water. The residue is calcined in a platinum crucible at a red heat. Domeyko says that, although quite accurdte results are not obtained by this process, still it is sufficient for most practical purposes. Cobalt is usually estimated commercially as oxyde, and nickel as metal. 100 parts of oxyde of nickel equal 78-7 parts of metal. , The assayer, however, before sending in the result of the 170 THE PRACTICAL ASS AVER. assay, must make a careful examination of these calcined oxydes, after having weighed them. The residue ought to be black oxyde of cobalt with a little nickel, if the ore is a cobalt one ; but of a dark green colour (generally speaking with one or two per cent, of cobalt) if the ore is nickel. To examine this residue, we first of all dissolve half a gramme in hydrochloric acid, and add water. Sulphuretted hydrbgen is then passed through the solution, to see if it contains copper. If a precipitate is formed, it is collected on a small filter, calcined, and estimated as oxyde. Its weight must be deducted from the result. If any arsenic is present, a yellow pre- cipitate will be formed. Another half gramme of the calcined oxydes is taken and dissolved in muriatic acid, and the liquor boiled. Water is added, and excess of ammonia, to see if iron and alumina are pre- sent. In case of an insoluble precipitate form- ing, the ammoniacal liquor is filtered, and the residue washed, dried, and calcined. Its weight must also be deducted from the result ASSAY OF NICKEL AND COBALT. \^l This will generally suffice for the practical assayer, particularly when the ore contains little or no nickel ; when, however, this latter is in considerable abundance, it becomes necessary to part the two. The following, though not ana- lytically exact, will be found tolerably correct, enough for commercial purposes generally : Take i gramme of the oxydes, and boil them in hydrochloric acid ; add a little sal ammoniac, and saturate the liquor with ammonia. If a little oxyde of cobalt is undissolved, add more acid, and ammonia in excess, until the residue remains clear without any residue. This solu- tion is immediately poured into a flask with a ground stopper, and about half a litre of dis^. tilled water is added, which has been previously well boiled, A solution of caustic potash is added and the flask closed immediately. Oxyde of nickel is precipitated, and oxyde of cobalt remains suspended in the solution. The liquor, when it has. lost all its blue colour, and remains red-coloured, is drawn off" by a syphon, and the oxyde of nickel well washed by boiling 172 THE PRACTICAL ASSAYER. water and estimated as, usual. The difference gives the cobalt. It should be remembered that, as the sale of cobalt and nickel ores is in the hands of a very few people who have their own assayers to go. by, the every-day assayer will not require perfectly accurate results, but only sufficiently accurate to enable himself or his employers to form a good estimate of the value of the pro- perty or ores. Even among professed cobalt assayers, differences of from 5 to lo per cent, are by no means uncommon. The sulphate of copper that is deposited by the sulpTiuretted hydrogen must be calcined in contact with air in a small crucible, and after- wards heated strongly in a platinum one, and then estimated. M . Terrell, in a communication to the " Bull, de la Soc. Chimique de Paris," 1866, has given the following excellent method for the separa- tion of these metals : To the solution of the metals, ammonia is added in excess, A solution of permanganate ASSAV OF NrCKEL AND COBALT. 173 of potash is also to be added in excess to the hot liquid : this point will be ascertained by the violet colour remaining for some little time. The whole is then to be heated to boiling, and then clorhydric acid added to dissolve the man- ganese. The liquor is then to be gently warmed for about 20 minutes, and put aside for 24 hours. All the cobalt will be found deposited in the form of a reddish violet powder, which is to be collected on a filter and washed with dilute clorhydric acid, and then -with alcohol. It can then be dried and weighed, (i 10° C.) '• The filtrate containing the nickel is boiled to expel alcohol, saturated with ammonia, and per- manganate of potash added. The solution is now boiled, when all the manganese precipitates, leaving only the nickel in solution. The nickel can now be separated in the form of sulphide, and changed afterwards into oxyde. 100 parts of the above violet powder equal 2 2-8 of metallic cobalt, or 29-0 of oxyde. Before the blow-pipe, cobalt affords the 174 THE PRACTICAL ASS AVER. characteristic "blue colour, giving off arsenical fumes. Arsenical nickel melts on charcoal, sending off white arsenical fumes. In the oxydizing flame with borax bead, it gives a violet colour while hot, and brown- red when cold. Dull grey colour in the reducing point. It may be added, as a conclusion to the above different methods of assay, that none of them are trustworthy, as a rule, except the half-dry and half- wet process, described at pp. i6i and following. ASSA Y OF SULPHUR. Take ioo grains of the ore to be examined, and act upon it by doses of nitric acid, precisely as described under cppper assay, till the sulphur is quite clean and yellow. When this point is attained, add hydrochloric acid, filter the solu- tion, wash, dry, and weigh the residue. Now ignite it in a small porcelain crucible, and the loss of weight will be sulphur (nearly). To the filtrate add chloride of barium in excess, and set the flask by for about two hours at a very gentle heat. Collect the precipitate care- fully in a filter, wash and ignite it as before ; every 1 1 6 parts of this sulphate of baryta cor- responds to 1 6 parts of sulphur. Calculate the amount, and add it to the previous amount found by ignition, and the two combined give the amount of sulphur. If the precipitate appears of a dirty yellow or brown colour, owing to iron mechanically carried down, wash the precipitate before filtering with hot dilute 176 THE PRACTICAL ASSAYER. hydrochloric acid. This method is tolerably correct for the estimation say of the amount of sulphur in a regulus for copper smelting. The sulphate, however, is slightly soluble in mode- rately diluted hydrochloric acid. It is a good plan to heat the filtrate, which should measure about lo ounces, to about i8o degrees F. If the solution, before precipitation, appears of a reddish colour, add a little hydrochloric acid. Let the precipitated flasks stand about eight hours before filtering. Wash repeatedly with boiling water and hydrochloric acid. Mr. Pearson says : " To remove any nitrate of baryta which may be thrown 4own with the sulphate, wash the precipitate with dilute acetate of ammonia. -An equal quantity of tartaric acid, added to the filtrate from in- solubles, prevents the precipitation of- iron compounds with the sulphate." ASSA Y FOR ARSENIC. Take ioo grains of the ore and. digest it in strong nitric acid till all action ceases, and the ore is quite decomposed. The action of the nitric acid, both in this and other assays, is very much facilitated by the addition of a crystal or two of chlorate of potash. Dilute with water, and filter the solution. To the filtrate add nitrate of lead ; arseniate and sul- phate of lead are thrown down ; collect on a filter ; wash, and digest with weak nitric acid, which dissolves the arseniate, but does not attack the sulphate. Filter the solution, and treat with soda in excess, which precipitates the arseniate ; collect, wash, dry, and weigh. Every lOO parts = 22*2 of metallic arsenic, or 29 of common white arsenic of the shops. N ASSA Y OF NITRATE OF SODA. ASSAY FOR MOISTURE. Weigh out any portion of your sample, say loo or 200 grains, and dry it carefully in a water bath, until it ceases to lose weight. The difference, of course, gives the moisture. The sample should be gradually dried for about three hours. ASSAY FOR SALT. The salt is determined by a standard solu- tion of silver, made as follows : Take i part of nitrate of silver, and dis- solve ,it in 30 parts of pure distilled water, or perhaps a little less. Now take i deci- gramme of pure salt and dissolve it in distilled water; run in your standard solution of silver, and note how many divisions on your burette are required to neutralize the chloride, and, consequently, note the standard ; say it re- quires 20 C. C. Take 5 grammes of the sample and dis- ASSA y OF NITRA TE OF SODA. 179 solve in distilled water; add a few drops of chromate of potash as a detector. Run in your standard solution of silver, as in a copper assay, until a permanent orange tinge is imparted to the solution after stirring, which shows that all the existing chlorides have been neutralized. Now read off the number of divisions, or C. C, required for this purpose, and, of course, the calculation is easy : thus, say it requires 15. Then 20 : 15 : : I : 75 X 2 = 1-5 of salt in 100 decigrammes of nitrate, or i'5 per cent. ASSAY FOR INSOLUBLES. Weigh out a quantity of your sample, and dissolve it in distilled water. Filter the liquid, wash, and afterwards ignite the filter : weigh the residue, and the difference gives the in- solubles. The filter must be well and carefully washed. ASSAY FOR SULPHATES. Take the filtrate from the preceding opera- tion, and add chloride of barium in excess ; i8o THE PRACTICAL ASSAYER. boil the solution, adding a few drops of hydro- chloric acid ;- filter the solution, and wash the filter thoroughly. Ignite the filter and weigh. The result is found by the following pro- portion : Sulphate of Sulphate of Quantity Barium. Soda. found. Answer. As ii7"5 is to ^i so is x to y. ASSAY OF GUANO. Moisture is determined in the usual manner, by drying in a water-bath, but it is exceedingly troublesome, owing to the disengagement of ammonia. Mr. Way states that if the substance is treated in a shallow platinum dish- with the addition of a few drops of hydrochloric acid, it may be dried at 2 1 2 degrees F. without loss. It is better, however, to make a combustion for nitirogen after the guano is dried ; if the amount of nitrogen found before drying is sub- tracted from the total nitrogen found in the fresh guano, and the difference between the two calculated as 2 (NHJ ^O, sCO^, we have the amount lost in the water-bath : now deduct this from the actual loss, and the true moisture is found. Organic matter \s found by taking 50 grains and burning off in a platinum crucible till nothing but ash is left. The ash of good guano ought i82 THE PRACTICAL ASSAYER. to be a perfect white. The heat should not be too high. Sand is found by taking the above and treating it with hydrochloric acid and water; when nothing more is dissolved, wash, dry, ignite, and weigh. Phosphates. — These are estimated by taking the filtrate and washings from the sand, slightly diluting it with water, and adding an excess of ammonia. The precipitated phosphates are collected on a filter, ignited, and weighed. The value of guano almost entirely depends on the quantity of nitrogen it contains,, so that the estimation of this is worth all the rest put together. Estimation of Nitrogen. — Most nitrogenized bodies, when heated with soda-lime, give off the whole of their nitrogen in the form of ammonia. This soda-lime is prepared by adding powdered quicklime to soda-lye of known strength, so that there are two parts of quicklime and one part of hydrate of sodium. The mixture must be evaporated to dryness in an iron pot, cal- ASSAY OF GUANO. 183 cined in a crucible, finally ground fine in a porcelain crucible, and kept in a close-stoppered bottle. If commercial soda is used, take care that no nitric acid is present. Weigh out the substance to be analysed (guano), and add to it, in a warm porcelain mortar, a quantity of the soda-lime, making up enough to about, or nearly, fill a common com- bustion tube two-thirds full. Now clean out the porcelain mortar with fresh soda-lime ; add this on top of the mixture already in the tube, and over all put a little fresh soda-lime; insert a plug of recently-ignited asbestos, and the tube is ready. Substances like guano ought td be mixed quickly to prevent loss of NH3. Church recommends that the mixture should be effected in the tube itself by means of a cork- screw shaped wire, taking care to leave an inch of pure soda^lime at the end. Give the tube a few gentle taps on the bench to allow a passage for the gas, and attach the ordinary nitrogen- bulbs or U tubes, containing 20 C. C. of dilute standard sulphuric acid. The bulbs are filled by 1 84 THE PRACTICAL ASS AVER. suction, and the whole apparatus must be quite air-tight. First heal the front of the combustion tube containing the pure soda-lime ; then, when this IS red-hot, heat the. mixture, keeping the front red-hot all the time, and soon gradually to the closed end. Finally, nip off the end of the tube, and draw air through the tube in the usual way. The acid contents of the bulbs are emptied into a beaker, some solution of litmus add'ed, and the quantity of free acid remaining estimated by a standard alkaline solution. From the amount of alkaline solution require d to effect this the percentage of ammonia may be readily ascertained. The litmus solution is prepared by digesting powdered litmus in twenty times its weight of distilled water for eight or ten hours, and then decanting it. Pour off half, and add a little very dilute nitric acid ; now mix the two together, and the whole will be violet, not red or blue. It should not be tightly corked. Fresenius's method of making standard acid and standard solutions is as follows : ASSAy OF GUANO. 185 Standard Acid. — Take 100 C. C. of strong hydrochloric acid, dilute to i litre, and well mix. Then measure out two quantities of 20 C. C. each, and determine the hydrochloric acid by means of nitrate of silver. If the two coincide, calculate the amount of hydrochloric acid in i C. C. of the solution, and mark the bottle accordingly. Standard Alkali. — Take 10 C. C. of ordinary potash or soda solution, add a little tincture of litrnus, and triturate with standard acid till red. Having thus roughly determined the strength of the solution, dilute a certain quantity of it till one volume will about neutralize one volume of the standard acid. Then, in order to stand- ardize the alkali exactly, measure off 20 C. C. ; add a little tincture of litmus, and run in the standard acid till the fluid is reddish purple ; boil for a minute or two (the blue colour will return if carbonic acid was present), add more acid as required, boil again, and so on till the fluid has a neutral tint not due to carbonic acid. Calculate the value of i C. C. of .the alkaline 1 86 ThE PRACTICAL ASS AVER. solution and mark the bottle accordingly. To free the alkali from carbonic acid before stand- ardizing it finally, boil it with some slaked lime, allow to settle in a nearly-closed flask, and draw off the clear fluid. Keep the solution in a well-stoppered bottle, or in a bottle through the cork^of which a tube containing soda-lime is passed. The two solutions may be made most advan- tageously in the following manner. I extract, by permission of the author, the following from Church's " Laboratory Guide," a book which every student of chemistry should have (3rd edition) : " Acid. — The acid, is a dilute solution of sul- phuric acid, of about \ normal strength; i.e., con- taining \ an equivalent of H^ S O^ (= % ="*49) in grammes in a litre. Preparation. — Take oil of vitriol, of which the percentage of H^ S O^ has been pretty nearly found out by its specific gravity. Say it con- tains 96 per cent. 28 C. C. of this acid, or, of course, an equivalent amount of other acid. ASSAV OF GUANO. 187 are measured into a beaker, diluted to a litre, and allowed to stand for twelve hours, in order that the lead sulphate may settle : decant the supernatant liquor, and filter the rest. Now ascertain its exact strength. Shake up, and measure into a beaker with the pipette, dilute with 200 C. C. of water and boil with hydrochloric acid. While the liquid is boil- ing, add gradually a boiling solution of barium chloride : stir well, and add till no further precipitation takes place. Boil the solution till no more barium sulphate falls down, and the liquor is quite clear. Filter the solution, and well wash the precipitate with boiling water. Dry, ignite, and weigh. The exact amount of S O3 per 20 C. C. must now be calculated. It is better to take three assays and strike the mean value. Alkali. — This is a weak solution of sodium or potassium hydrate, of which 100 C. C. = exactly 20 C. C. of the acid. The caustic soda made from sodium is the best substance to use. 1 88 THE PRACTICAL ASSAYER. Preparation. — Say we are going to make two litres of alkali solution, out of sodium hy- drate. If the acid contains exactly 49 grammes of Hj, SO^ in a litre = '98 grammes in 20 C.C., » since H, SO^ saturates 2 N^ HO, we have — H, SO, 2 N, HO in 20 C. C in 100 C. C. 98 : 80 = -98 : -8 N, HO C.C. N,HO C.C. taken N^HO required 100 : -8 = a : x Weigh out the amount and add water to about three-quarters of the volume required; now dilute gradually down to the exact standard of 100 C. C. of the alkali == 20 C. C. of the acid. Keep this solution in well stoppered bottles, in a cold place. Now determine the exact value of each C. C. of this alkali. Since H^ SO, saturates 2 NH3, if the two solutions are made as above, — H,SO, 2NH3 in 20 C.C. NH3 98 : 34 = -98 : -34 Therefore each C. C. of alkali solution ^ ^ = -0034 gramme of "ammonia, or "0028 ASSAy OF GUANO. 189 of nitrogen, as we have already got 100 C. C. = 20 C. C. of the acid. Suppose, after a nitrogen combustion, the contents of the bulbs require 65 C. C. to neutralize them, it is plain that the acid lias absorbed ammonia equal in saturating power to 35 C. C. of the alkali. So 35 X '0034 = •! 19, the weight of ammonia obtained, or 35 x .0028 = -098 weight of nitrogen, from which the percentage is ob- tained. Miller, in -his " Elements of Chemistry," gives the following method of estimating the ammonia. 10 grammes of the guano are placed in a small retort, and 100 C. C. of water are added ; by means of a bent funnel 25 C. C. of a solution of potash, of specific gravity i "25, are also introdiiced ; 50 or 60 C. C. of liquid are gradually distilled over into a beaker (by means of a bent tube fixed on to the end of the retort) which contains 100 C. C. of sulphuric acid, diluted to the required strength. As soon as 50 or 60 C. C. have passed over, allow the retort to eool, and 40 C. C. of water are added 190 THE PRACTICAL ASSAYER. to the retort ; distil again till this 40 C. C. has passed over, and once more repeat the same operation. A few drops of litmus are now added to the contents of the beaker, and the acid is neutralized by the standard alkali (caustic soda). This solution should be of such a strength that i C. C. equals an equal amount of acid solution originally introduced into the beaker. Suppose, now, this acid solution in the flask requires 67 C.C. of alkali solution, instead of 100. It is evident that 33 C. C. have been neutralized by the ammonia ; a quantity of ammonia has passed over therefore = to 3*3 grammes of anhydrous soda. From the two equivalents of the two alkalies, we may cal- culate the ammonia thus : Na20 H3N 31 : 17 : : 3"3 : I'Sog x ip or 1 8 -09 per cent, of ammonia in the sample, if 10 grammes are taken. This inethod is easy, quick, and tolerably accurate. The alkalies are generally determined by ASSAY OF GUANO. igi difference, at least for commercial purposes, but the phosphorus pentoxyde should be deter- mined. The filtrate from the phosphates is concen- trated, and a little ammonium oxalate added. If a decided precipitate takes place, phosphoric pentoxyde is only present in traces, and need not be looked for any more. If ammonium oxalate produces no precipitate, filter the solu- tion if requisite, and treat with magnesium sulphate and great excess of ammonia. Collect, dry, and ignite the precipitate of ammonium magnesium phosphate. The Mg^P^O, is cal- culated into phosphorus pentoxyde. A still better method is the following : The clear and dilute phosphate solution is treated with ammonia in slight excess : dilute acetic acid is added until the precipitate is entirely redissolved. An excess of acetic acid is to be avoided. Any insoluble residue must be removed by filtration. Uranium acetate is now added, and the whole boiled. The uranium phosphate is allowed to subside, and then tho- ■192 THE PRACTICAL ASS AVER. roughly washed by decantation, boiling water containing acetate of ammonia being used for this purpose. Finally, get the precipitate on a filter, dry, ignite, and weigh. But before weighing, the precipitate should be moistened with strong nitric acid and ignited again. It should come out a bright yellow; one part = "1991 of phosphorus pentoxyde. Concentrate the filtrate and precipitate the uranium by cold anjmonia, covering over the vessel. Wash the precipitate twice by decanta- tion, and then boil it with a solution of ammo- nium chloride. Collect on a filter, and estimate the lime and magnesia as usual." APPENDIX. COPPER SMELTING IN CHILE. To attempt anything approaching a complete account of the mining resources and copper manufactures of Chile would, from obvious reasons, require a very extended experience, and a very intimate acquaintance with the actual working of more than, perhaps, one hundred establishments, at pre- sent engaged in such pursuits in that country. The reader may readily imagine the difficulties, alinost impossibility, attending such a task, when I state that Chile produces about half the total amount of copper of the whole world, and directly or indirectly employs about half her popula- tion in the working of it In fact, I doubt whether any one man could write a complete account of this subject, in view of the many different principles, systems, and conditions under which establishments are conducted in Chile. As, however, the copper interests of Chile seem to have been strangely misunderstood at home, perhaps a few data on the subject may be" of some interest, at least to our home smelters. I premise, first of all, that I cannot wholly guarantee the correctness of all the following state- ments and deductions, but can only give my readers a general idea of the working and smelting of ores, leaving- to them to criticise the correctness of the financial results ; O 194 THE PRACTICAL ASSAYER. and, secondly, that most of the said data and statements are drawn from a rather exceptional source — the establish- ment of Guayacan — exceptional for reasons hereafter stated. Copper smelting, also, seems as yet very imperfectly un- derstood, at least some important facts concerning it. For instance, it has never yet been demonstrated clearly whether an " over-poled " ingot of copper has absorbed carbon, or whether it is due to the total reduction of the dioxyde of copper ; in other words, whether a certain amount of oxyde is not essential to its malleability. The precise action. of oxyde of copper has never been accurately defined ; no one has succeeded in giving a final and decisive reason why an ingot, ladled under certain conditions, rises in the mould ; whether it is due to the air of the atmosphere, or sulphur- ous acid ; and why, on the other hand, the ingot some- times has a slight depression in the centre in cooling in the mould. Imagine the fortune a man might make who would discover a process for getting rid of the sulphur in the operation of making blister, without consuming some tons of coal, and the best part of a day ! One of the cleverest of metallurgists, Le Play, devoted a very considerable portion of his time and talents to the drawing out of elaborate calqulations and statements with regard to the smelting of copper, and the profits to be derived from it. As this gentleman had access to several important works in England, his theories were accepted by five unfortunate companies as somewhere near the practical truth,.and all five suspended operations after a short existence, showing that a man may be a very clever theoretical chemist and yet a very poor smelter and seller. The Mexican and South American Company, which formerly existed in Guay- acan Bay, not two miles from the present Guayacan works seemingly started with the fairest prospects; abundant capital, near the richest mines in the world, with a good APPENDJX. I9S harbour, and good smelters, including Mr. Francis, the pre- sent head smelter at Guayacan. Yet it failed, and people blamed the system of smelting, the fact being that the very same system is at present employed at Guayacan. The real cause of failure of that company was bad management and distance from their base of operations, the board of " directors being in England; consequently, disputes which are easily settled when the chiefs are on the spot, promise to be endless when lengthy and tedious correspondence has to be carried on with the home board. Anyone who knows the unceasing activity, above all other things, which the management of a copper works requires, can readily understand the defect of such a system. Shortly before the company subsided, a lawyer was actually sent out from England to take charge of the works. The result can easily be imagined. The system of smelting pursued at Guayacan differs materially from any other. ^t is what is called "Napier's im- proved process." The great advantage the Chile smelters here have is that they are enabled, by their " coloured " ores, to bring up the ley of the regulus at one operation to a pitch of 45 or 50 per cent., thus saving an immense deal of time and trouble. As regards the finaneial results, I may as well state that having been connected with the Guayacan Copper Works, I am not at liberty to enter into very particular details as regards profits, &c. One of the very best smelters in Chile, however, told me that as a general rule companies must be satisfied with 7 per cent, on their capital. Indeed, state- ments about copper smelting are so contradictory that it is useless to try and give a rule for the regulation of profits. Some people think that all a smelter has to do is-to put the ores into the furnace and tap out copper and 1 5 per cent, dividends; the fact being that as much depends on the 196 THE PRACTICAL ASSAYER. financial as on the smelting operations. I have premised so much as a sort of apology for, I daresay, some few errors in my calculations and statements. Of course, everyone, down' to the office-boy in a copper works, thinks he knows all about smelting, but I am quite sure I could enumerate all the good smelters I know on my five fingers. We will take first the ores, then the furnaces, and then the mode of smelting, and prices. Ores. — All ores in Chile are divided into two classes, bronces and color — sulphurets and carbonates. There are several sorts of sulphurets. First, the yellow sulphurets, with quartz and silica as their basis ; most of these come from the north of Chile. Secondly; those with lime and silica for their base ; these come principally from Tamaya and that neigh- bourhood. And we have also the bronce morado (purple ore), and the black sulphuret (bronce negro).; the former principally from the Tamaya region, and the latter from different parts of the province ofCoquimbo. The carbonates, or " color" ores, contain, of course, a minimum of sulphur. Those which have much silica in their composition, and are difficult of fusion, are called " secos," or dry metals; these form the' largest portion of the ores. Those which contain a good deal of carbonate of lime or iron, and are easily fused, are called " blandos,'' or soft. Besides these we have a good deal of the carbon- ate ore known as color bronceado, and other kinds of ore bought firom the " Pirquineros " in small lots. The- source from which the ores used at Guayacan is derived is the Tamaya regioil, the most important of the mines belonging to Mr. Urmeneta, the head partner of Guayacan. The average ley of the whole Tamaya region may be put at from 15 to 16 per cent, and the whole pro- duction as something over 45,000 English tons yearly. The class of ore principally produced is a sulphuret, very pure APPENDIX. 197 in quality, and free from injurious metals, such as arsenic, antimony, &c. Carbonates are principally obtained from the Sarco district, which produces ores of an exceeding purity and richness. Carrizal also sends large quantities of yellow sulphurets. One of the great advantages which Guayacan has over other establishments is that the ores are very pure, and are usually in such abundance that the smelter can afford to pick and choose, instead of, as is frequently the case, having to, put up with whatever he can get. Although, as I slated above, the average ley of the ores smelted at Guayacan may be put down at 15 per cent., yet another company on the coast would have to reckon on 12 per cent, as the out- side limit of the ores at their disposal. So much, then for the ores. Furnaces. — The universal furnace used throughout Chile is the ordinary reverberatory one. The furnaces at Guaya- can are constructed to hold, more or less, 8 tons, the charge consisting of two lots of 4 tons each ; the first one is melted down in the usual manner, cleaned, &c., and the second one is introduced. The furnace is then manipulated in the ordinary manner, and is tapped on two charges. At Carrizal the fiimaces of the company are somewhat larger, being built to hold charges of 9 or 10 tons. The following are the dimensions of an ordinary furnace : — length outside, including grate Feet 28 o Width outside 16 o Grate ■• 6 o Length inside to bridge 18 o Breadth in middle 12 o Breadth in mouth 2 o Breadth in bridge 5 7 Height in middle'! 3 7 Height in mouth y from bricks 2 5 Height in bridge J ., 4 o Length of bridge inside S 7 Length of brid-ic outside , 4 o igS THE PRACTICAL ASSAYER. Height of bridge Feet 2 o Breadth of bridge 2 7 Fire-place 4 "feet square inside. Height from top of bridge to roof 2 o Width of flue is 18 inches. The thickness of the sides is twft bricks and a half. Slope, from grate to hole, 30 inches, or 7 bricks ; the corners are filled in solid ; the bed is formed of 12 inches of quijo, or crushed quartz. A furnace will take about 30,000 bricks (if with culverts), and, more or less, 150 qntls. of iron in iis construction. Its cost may be put down at about ;£ 600 in complete running order. There are two refineries atGuayacan, one holding 14 tons and the other 20 tons. Out of this latter over 2000 ingots have been ladled, averaging loo to the ton. They are of the same construction as the others, but they are, of course, fed by side holes, and not by hoppers. The calciners at Guayacan are about 40 ft. long, including grate and all. They are constructed with three consecutive floors, divided from each other by a bridge, and each a few inches lower than the one above. Over the first, or one farthest from the fire, is placed the hopper ; into this the charge is put, consisting of 4 tons of regulus. After a calcination of from I o to 12 hours in the first floor it is raked down by paddles to the second floor below, and there calcined 10 hours. Meanwhile, another fresh charge is placed on the first floor, and the one on the second raked down to the third, and so on, following each other. After about 35 hours calcining in all, the lowest floor, or one nearest the fire, is raked out through a hole in the side into a pit below ; water is then thrown on it, and it is ready for the bar furnace mixtures ; this calcined regulus has now about 3 per cent, of sulphur. There are 17 of these furnaces at Guayacan. Brunton's revolving calciner was also tried, but after a short trial was abandoned. Great care must be taken to regulate the heat APPENDIX. 199 of these calciners so as not to let the regulus cake, which would delay its thorough calcination. This accident can be easily avoided by taking care that the -charge next the fire is heated as much as possible without caking ; in this casfe the other charges will have just the required heat. Many furnaces are prematurely ruined by being used too soon after building. The proper course is to let the wooden props used in its construction burn slowly away, and the length of time required for a furnace to dry is, at least,- eight days with a slow fire. The bricks used are principally Lota, and Diiias when they can get. them. The difierence between them is enormous ; a roof constructed of Lota will burn through in a fortnight, while one of Dinas bricks will stand six months. The coal comes principally from the south of Chile — Lota and Lebu ; some English coal is also used for the refinery. In the big 2o-ton refinery a sufficient heat could not be got on with the Chile coal, but it answered very well with the smaller 14-ton furnace. Puchoco "lower vein" is one of the best smelting coals when pure ; therb are two sorts, "upper" and "lower," and the company are supposed to sell " half-and-half." The coal from Coronel is a very dull, blow coal, and that from Lebu is 25 per cent. dirt. Some experiments were carried out to ascertain the proportionate value of the different classes of coal, and it was discovered thit the average Chile- coal, if tolerably pure, was at the price nearly equal to English. We will consider the pay of the workmen as we describe the operations in each furnace. Supposing, then, that we have our furnace in running order, we proceed as follows : — Before charging the furnace we throw in a quantity of slag to fill up the interstices at the bottom ; when this slag is melted we introduce the charge. Supposing everything has proceeded satisfactorily, we tap 2c» THE PRACTICAL ASSAYER. out and examine the slags ; in them we may find pieces of regulus, or shots of copper. If we find regulus we may be pretty certain that the slag has not been sufficiently fluid to allow the regulus to fall to the bottom ; we, therefore, must add more ferruginous ores to our mixture, and take care that we get sufficient heat on the furnace. If, however, we find shots of copper in our slag, we know that there has not been sufficient sulphur in our mixture to reduce the oxyde and form regulus, and, therefore, we must add more sulphurets. While the charge of regulus is still running out, the bottom of the bin is pulled out, and the fresh charge allowed to fall into the furnace ; it is then spread evenly all over the bottom, the door closed, the bin closed up, and a fresh charge placed in it ready for use, and all the openings, &:c., stopped up with clay. If, however, the ores contain a great abundance of sulphur the door is left open for them to calcine a little. The charge now roasts itself, but great skill is required in attending to the fire to regulate the heat with' as little coal as possible, as the test of good smelting is the proportion of coal to ores smelted. The whole opera- tion for one charge takes about four hours, with good coal and average ores. At this point the smelter takes down the door, and examines the charge : he stirs it well, skimming off lumps of quartz and other matters that are not fusible, scraping up the bottom, &c. The furnace is again closed and the fire pushed on briskly, when it is skimmed, care being taken that no regulus is taken off with the slags, and that a thin layer is left to cover the regulus on top. After this the fire is urged for a few minutes to its utmost, and the furnace is then tapped into sand-moulds. After frequent smeltings with ferruginous ores the fiimace will get corroded, especially by the " wash " of the metal ; this is caused by the silica in the bricks combining with the iron in the ores. APPENDIX. 20I These defective places are repaired by crushed quartz, or, as it is called, quijo. It will be seen that copper is obtained by this method at one operation. The regulus made is of an excellent quality and of an average ley of 48 per cent. It will be frequently observed that a grate may get a very good heat on, almost enough to melt the bars, and yet there is comparatively little heat in the ore. The reason is that there is need of more room, or " play," in the stack for the current of air. Gersten- hoffers were tried at Guayacan, but it was found that they did not bring regulus far enough on — in other words, did not calcine it sufficiently ; consequently, in the bar charges so much sulphur remained in the regulus that the charge came out almost all white metal. I am informed, however, that these calcines are only used as a partial process in Germany, and at Guayacan they misunderstood them altogether : any- how, they were found too expensive for Chile, where economy is everything. I shall now consider the operations of making regulus, bar copper, blister, and ingot, in their order. Operation I. — Making Regulus.-^ln this operation we must have yellow sulphurets in our mixture ; if, however, we were to smelt these alone we should only get a regulus of about 25 per cent., or at most 30 percent.; if we calcined them in the open air the percentage would reach 45 or 48 per cent, of copper, which ley would ensure good slags. If we can secure plenty of good bronce morado, or metal de color, for making our mixture, we need not calcine the ore, unless we wish to liberate iron in order to flux the silica, so as to get a good slag ; so that if we have abundance of yellow sulphurets with no free iron in their composition, or which contain a large amount _of silica, calcination is required. The objects to be attained in this operation are (i) a charge easily fused, and which gives good slags ; and (2) a charge THE PRACTICAL ASS AVER. which will give a regulus -more or less of 50 per cent. Generally speaking a charge will contain from >^ to J^ its quantity of yellow sulphurets, because the quality of the regulus depends on the relative quantity of sulphur and copper in the ore. We now have our regulus ; the next step is — Operation II. — Making Bar Copper. — The furnace is pre- cisely the same as for the first operation. The regulus is first taken to a mill and crushed ; the mills in use at Guayacan are the old-fashioned cylindrical rolls of a very ancient type, and crush about 90 tons of soft regulus a day ; the powdered regulus is then passed through a sieve of 64 holes to the square inch. It is then placed in the calcining furnaces, as described above, and calcined for about 35 or 40 hours, to extract the sulphur, or, rather, all but about 3 per cent. When the powdered regulus is put in the furnace its com- position is about as follows : 50 per cent, of copper, 25 of iron, and 25 of sulphur, equal to 100 per cent. And" when taken out — 50 per cent, of copper, and 25 of iron, oxydized ; and 3 per cent, of sulphur. The charge for making bar copper is, more or less, as follows : Regulus... Qtls. 27 '00 or Regulus... Qtls. 27-50 J Sulphurets i'52 ,, Sulphurets 2*05 ( Average ley, 35 '5 Carbonates 7'48 ,, Carbonates 7'I5 ( percent. Slags 4'oo ,, Slags S'^S ) Cp^j J 3-oo„ j^?^^-- '"'"f Fluxes. Cinders { ^ " j Cinders 1-55 j Qtls. 43-00 Qtls. 43-20 As the furnace is tapped on two charges we get, niore or less, the following result : 17-20 kilos, bar copper =97 per cent. 14-70 kilos, white metal =65 per cent. Expressed as follows : Charge (not including fluxes), 75 qtls. APPENDIX. 203 by 35 per cent, (-s being allowed as loss) = 26-25 fine copper = tap out. I7"20 kilos, bar, at 97 per cent = i6'69 kilos. 1470 kilos, white metal, at 65 per cent. ..-= 956 kilos.. 3 1 -90 kilos, Fine copper. 26-25 kilos. A furnace in full work turns out in the day about 56-00 kilos, of bar and white metal in the above proportions. In these furnaces 2 tons of ore are smelted to i ton of coal. Of course it will be seen that the oxyde of iron in the cal- cined regulus combines with the silica in the carbonates, forming a fusible slag. The coal and cinders are added to reduce the copper. The same precautions are necessary in the skimming and tapping of these furnaces as noted in the former ones. From all the carbonate ores we get copper at one operation, but as the regulus is, of course, not totally calcined, and the ores contain sulphur as well, we get a large amount of " white metal," which is subsequently roasted into blister, and afterwards refined into ingots. We might, ■however, if we chose, refine the bars at once, in 7 or 8 ton charges, in from 20 to 24 hours. From 17 to 18 bars are produced in each tapping, or (say) 3 tons in the 24 hours. The slag, &c , from the tappings come in from fluxes in other charges ; the guaranteed ley of the bars is 96, per cent., and they generally reach 97 -5 percent. Sometimes there is danger of some regulus getting "layered" in between the solid copper, by reason of a bad and thick slag, and thereby deteriorating both the ley and the quality of the bars. The bars avera,ge about nine- to the ton. ' The relative propor- tion of ingots and bars produced in an establishment turning out 8000 tons a year, would be, more or less, as 3 to 5, or 3000 tons ingots and 5000 tons bars. The principal reason why the regulus is calcined so much is because there is not sufficient coloured metals to carry off the superfluous sulphur 204 THE PRACTICAL ASSAYER. which the regulus would have if not calcined. The metales bronceados, having but little oxygen and sulphur, are of course mixed up in small quantities with the other ores. The operations that take place in the furnace are as follows : the coal and cinders will reduce the copper which falls to the bottom of the furnace, the sulphur combines with the oxygen of the air and goes off as sulphurous acid, and the silica combines with the iron in the ore and forms a fusible and liquid slag. Supposing the ley of our bars comes out low, or below guaranteed value of 96 per cent., we must continue a low heat for some considerable time, and the furnace must be well rabbled up, with the addition, if pos-- sible, of more green carbonates and reducing agents to our mixture ; if, however, we find the ley of our bars too high — that is to say, 98 or 99 per cent. — we know that we have reduced too much oxyde of copper; this was the reason why the old Chile bars' were so superior to the present ones ; the old smelters were too poor to put up calciners, crushers, &c., and so they had to put their ores in raw, — in " colpas," smelting them with wood ; the carbon in the wood fire reduced more oxyde and sulphur, and the ley of the bars consequently rose to 99 per cent, frequently, but the smelter was only paid, as now, for 96 per cent. The old smelters, when their metals were poor, used to run down two charges and then introduce a third ohaxge^ of rich carbonates on top, and tap on three. Two men only work each of the above-mentioned cal- ciners, charging, coaling, paddling, and everything ; they work each 24 hours on a stretch, and are paid I2, or 8j., each. The bar furnaces have two maestras, or masters, and two helpers {qfficiales ) each, working 24 hours. The masters get 2C. a Spanish quintal on all the ores put in the furnace, and they have to pay out of this $1 to each of the two helps. APPENDIX. 20S Supposing, then, that a charge consists of 70 qntls., and we smelt 3j^ charges a day, if a furnace is in good working trim, a master's pay would be 150 qntls. by 4"3-ioths c. (equivalent to 2c. Spanish), which amounts to$6'5oc., or less %2 for the two helps = $4*5oc., or $67"Soc. a month. The helps really earn only 7 reals, or 3J. (id. each, as the real, or 6i/., is left towards charging tTie furnace at night. The bars, when they leave the beds, are covered with spots of regulus, dirt, sand, &c., and are cleaned and trimmed by contract at the rate of 8c. per 3 bars. Two tappings a day is considered good work, which is about equal to 3 tons of bar copper ; this amount would not be obtained unless with first-rate coal, as bad coal necessitates frequent skimming and removing of the door, which cools the furnace and throws it back. The large cake at the mouth-bed of the furnace is always broken up and used in the charges again ; it contains a good deal of quijo, copper, regulus, &c. The first and second beds' on each side of the furnace mouth also contain a good deal of regulus, which comes out with the unmelted quijo and quartz ; they also are, of course, resmelted. Operation III. — Making Blister Copper. — The charge consists, more or less, of 7 tons of white metal from the bar furnaces, introduced into a furnace constructed precisely like the latter, with the exception of having two air-holes on each side of the bridge,, diagonally directed over the charge. To commence with, the air-holes are opened and the fire pushed on brisk, whilst the charge gradually melts down, which should be in about six hours; it drips down like melted bacon, and when it is melted the air-holes are closed tightly and the fire raked up to form a slag, which rises in about four hours, and is carefully skimmed off; when the face of the bath is pretty well cleaned, the front door is put up and the air-holes opened again, which cools the furnace slightly and cakes the slag, which so can be easily cleaned 2o6 THE PRACTICAL. ASS A YER. off. This latter slag is very rich, and carries off most of the impurities, as antimony, arsenic, &c., &c. ; the charge is then allowed to roast again, and is again skimmed, a^ soon as a slag forms, as at first ; this usually happens three times. After the first skimming the metal begins to '' work " — i.e., boil up with a frizzling sound exactly like a frying-pan of melting fat — the furnace being kept at such a heat as to keep the metal in a half-viscid state. At the end of 24 or 30 hours, according to the fineness of the metal put in, the white metal gradually boils off the face of the copper below, and the latter, as its face clears, changes its frizzling, pasty appearance, and appears exactly like a pool of water into which rain-drops are continually falling ; should there be any holes or faulty places in the furnace bottom the cop- per will boil up from them like a miniature volcano, and the smelter must not be alarmed at this symptom. From this point the bath must be constantly watched. Generally, in one and a half or two hours after it has assumed the last- mentioned appearance the surface of the copper gets gradu- ally more and more quiescent, until at last (with the excep- tion of the before-mentioned volcanoes, if the bottom be faulty) it becomes perfectly smooth. Now is the critical time, for if the operation has beefi well conducted there ought to a,ppear in about a quarter of an hour afterwards a slight ripple on the surface of the bath, just like a ruffled pool, accompanied by a peculiar dark scaly substance floating on the top. Immediately this appears, the air-holes are closed and the fire pushed on for 10 minutes, . when the furnace is tapped out into sand moulds as blister copper. If it has been tapped too soon there will be formed minia- ture fountains in the beds, caused by the sulphur trying to force its way out. Good metal takes about 24 hours to ' ' roast, and requires more heat on, and coarse metal about 30 hours. Supposing a charge of 7 tons is taken, about 5 tons APPENDIX. 207 of blister will be obtained. Iii this operation the whole of the iron and most of the sulphur are driven off, the former being skimmed off with the slag, and the sulphur, combining with the oxygen of the air, going off in the form of sulphur- ous acid. What little sulphur does remain is subsequently roasted off in the operation of refining. These roasters are fed by a side hole, and have no hopper. By reason of the continued heat to which the furnace is subjected, the bottom frequently rises very much — that is, it cakes, and the copper gets under and raises it up, entailing a loss of copper in the tapping, and the bed gets extremely hard and difficult to break up.' A roaster bed will absorb sometimes as much as 1 5 tons of copper. Loza, or broken sea shells, is found to stand better than anything else, though some smelters use plain brick floors with fair results. In Germany they use an iron floor supported on four columns, and build the bed of the furnace on that ; suppos- ing the copper goes througB, it cools before reaching the ground underneath. Four men charge the roasters and carry away the pigs, &c., to their destination ; 6 reals, or 3J., is paid for charging a roaster, and so much a bed for moving. The "sharp" slag from the roasters averages about 10 per cent., and the "roaster" slag about 30 per cent, all of which is of course returned to the bar furnaces. The men who attend to the roasters are also employed at the refinery, and are paid 150 per month ; 7 reals, or 3J. dd., is paid to the helper, or official, as he is called, per day of 1 2 hours, exclusive of the pay for charging the fur- nace. Sometimes the furnace will not stand the requisite heat for bringing on the copper to blister, in which case it is brought on to sponge copper only. It is rather curious that the slag gets thicker the farther it gets towards sponge, and- thinner from sponge to blister ; this is owing, I presume, to the greater heat. 2o8 THE PRACTICAL ASSAYER. Operation IV. — Refining for Ingots. — The charge consists of four beds of the roasters, or 20 tons blister copper: The time generally required to refine the charge is about 1 6 or 1 7 hours. Four hours before charging, a large quantity of cactus root is thrown in at the door of the. furnace, and two or three hours after the bath is well poled. This opera- tion is conducted by protruding] a pole of lumas wood through the door of the furnace, and pressing it well over to the bottonij in order to expose as much as possible of the copper to the action of the carbon ; it usually takes about an hour's poling to bring the copper up to the proper pitch. The face of the bath is then covered with fine anthracite coal, to prevent oxydation by the air, and the metal is then ready for fadling. The object of the poling is, of course, to reduce the oxyde tjiat is contained in the melted copper, and upon the excellence of the poling does the refining greatly depend ; the presence of an oxyde would, of course, render the copper brittle. Usually two tests axe taken to ascertain if the copper is at a proper pitch. They are taken as follows : Two ladles, lined with clay, are filled with copper from the furnace, and placed to cool in a horizontal position. If the 'copper is at the right pitch, these tests should set perfectly free from the smallest trace of .rising or volcanoes, and when perfectly cool should contain a slight circular depression in the centre about yi in. de^p, in a 20-lb. ladle. The surface must not present any appearance of longitudinal or horizontal depressions or lines, but that of, more than anything else I can liken it to, a piece of coarse wrinkled skin, the wrinkles extending in no particular direction. An ingot when cooled should' be as near as possible flat, slightly wrinkled, and the rim slightly raised all round equally — in fact, a good ingot (for alloy?) may be compared to an oblong pool of water almost full. In pour- ing , an ingot into the mould care must be taken to pour APPENDIX. 209 evenly and gradually, or the appearance of it will be spoiled. ■The copper is ladled as quickly as possible by four or five men at a time, to prevent the bath of metal going out of pitch. To prevent this during ladling some billets of vifood are thrown in at the door of the furnace ; but even with every precaution the copper sometimes goes back, entailing sometimes two or three hours to bring it on again : 100 copper moulds are ranged on iron chairs round the front of ■ the furnace, each round being, more or less, a ton of ingots. Besides these there are the moulds themselves to be made, which contain two ladles full of copper apiece ; three of these are run at the end of each round, so that in a 19-ton charge 5 7 moulds would be made ; for making these the men get no extra pay. In the large 20-ton refinery English coal is burnt, as it was found that a sufficiently strong heat could not be got on the furnace with Chile coal ; but in the new 14-ton refinery Chile coal does well enough. The large fiimace consumes about 5J^ tons of coal in a day, and i ton of anthracite coal for every 50 tons of ingots produced. The number of lumas poles required may be put down as one pole to every ij^ ton of copper, and taking a copper works all through about 3 J^ tons of coal are required to produce a ton of fine copper. The cactus roots, mentioned above, contain a good deal of moisture, and, as it is technically called, " cools " the copper. In charging the refinery care must be taken to clean the blister well, to prevent the sand rising and mixing with the slag ; this arises from carelessness in stepping in the sand moulds when made. After the furnace has been poled it is skimmed perfectly clean : this throws it back a little, but the coal subsequently thrown on brings it on again ; the fire has meanwhile not been banked up, but if the test ingot is satisfactory the fire is stuffed quite tight before ladling. P 2IO THE PRACTICAL ASSAYER. Four men charge the furnace, and i2j^c. are paid per ton for charging. A royally of 62 J^c. a ton is paid to the ladlers, who, as before stated, receive 850 a month wages for the roasters as well. It costs as near as possible $5 per ton to refine copper ; roasting costs about the same, calcin- ing, more or less, $3 "So the ton, and crushing about 27c. or 30c. Conversion from regulus to bar may be calculated at from $4 to $4'So a ton. The loss in a copper works all through may be put down at somewhere about ij^ per cent. One of the most astonishing things connected with this subject is the enormous amount that gets collected in the culverts. In large works, producing 9000 tons a year, the quantity amounts to not less than 350 tons annually of an average ley of 35 per cent.; of course this is recovered and re- Stnelted. The question arises, how much goes out of the chimneys ? As regards profits to be made by copper smelting, it is impossible to ^ive anything like a correct idea, as every- thing depends on management ; in fact, I would be bound to say that anyone might have access to the books of the most successful company, and yet start for himself and lose money. A great deal depends on the difierent systems pursued. I may, however, state that '780. is usually considered an average price for reducing i quintal of 15 per cent, ores to regulus, and about $40 to I42 for reducing regulus to bar copper, per ton of fine copper. Generally speaking, however, companies would have to calculate %\ and $46 respectively. This formula is supposed to cover all expenses after the ore is actually on the ground. Supposing, then, we take 68 quintals of ig per cent, ore, it wUl give us about 1 quintal fine copper, allowing for trifling waste. Supposing we pay for it at the rate of, say, i ■42c. for 10 per cent, with a •23c. rising scale, we get, more or APPENDIX. 2U less, as the value of the ores, $i75"oo. Adding a trifle less than a dollar for conversion to regulus, we get, say, $246"oo in the form of regulus ; with an addition of $45 for con- version to bar, we have $285 "oo ; bar copper being quoted on shore at $297*00, this leaves a profit of $1 2, or £,2 lof., more or less, a ton ; that is to say, that a company turning out 5000 tons of ingots and bars ought to show a profit of from ;^i2,ooo to ;£rs,ooo a year. It is obviously im- possible to give any formula, however. Supposing, for instance, a smelter has a contract with a large mine to deliver so many tons a month for one year at a fixed price ; copper goes up ;^i5 a ton, and the smelter, of course, as he does not pay any more for labour or coal, reaps the entire benefit of this rise. Ores are bought in Chile either at a fixed contract price, or by the price quoted of bar copper, allowance being made for the conversion of the ores to copper. When it is sold at a fixed rate, a point is taken, say of 10 per cent. Thus, 10 per cent, is worth, for example, 140c., and for every unit over 10 per cent. 2Sc. is paid; then for 12 per cent, ores of course 140+500.= 190c. would be paid, and so on. When regulated by the price of copper, an example may be given thus : When bar copper is quoted i4*4oc a Spanish quintal on the coast, 650., more or less, would be paid for a quintal of 10 per cent., and 13c. for every unit over placed in smelter's establishment. So we have on 15 per cent, ores, 10 = 65 and 5 X 13 = 65 ^ li '30 for i quintal of 15 per cent, ores, Spanish weight. Now, 147 Spanish quintals are required, more or less, to produce a ton of fine copper, so multiplying 147 by f3o = ligi'io, adding 78c. and $42 respectively for conversion, we have an apparent profit of S24, as copper is subject to a 33c. reduction for duties, &c., which makes the price $14-40— -33 = 514-17 as price o fi ton of copper on shore. Interest, commission, brokerage, loss, &c., 212 THE PRA CTICAL ASS A YER. must be deducted from this. As regards costs of works, &c., I have been informed that an establishment capable pf turning out 8000 tons yearly could not be erected under ;^3o,ooo to ;^4o,ooo, and the capital required to carry it on should not be less than ^^^i 60,000. By no known method, I believe, can money be so quickly lost as in copper works badly managed, but that copper-smelting in Chile, properly managed, pays, and pays well, I have no doubt. TABLES , For Determining the Standard of ant Silver Alloy by Employing an Amount of Alloy approximately CONTAINmo THE SAME Amount of Silver. 214 THE PRACTICAL ASS AVER. Tables for Determining the Standard of any Silver approximately containing NITRATE OF Weight of Assay in 1 2 3 4 MiUigrs. lOOO looo-o 999-0 998-0 997-0 996*0 1005 995 'o 994-0 993-0 9920 991-0 lOIO 9901 989-1 988-1 987-1 986-1 IOI5 985-2 984-2 983-2 982-3 981-3 1020 980-4 979-4 978-4 977-4 976-5 1025 97S"6 974-6 973-7 972-7 971-7 1030 970-9 969-9 968-9 968-0 967-0 1035 966-2 965-2 964-2 963-3 962-3 1040 961-5 960-6 959-6 958-6 957-7 104s 956-9 956-0 955-0 954-1 953-1 1050 952-4 951-4 950-5 949-5 948-6 1055 947-9 946-9 9460 945-0 944-1 1060 943-4 942-4 941-5 940-6 939-6 1065 939-0 938-0 937-1 936-1 935-2 1070 934-6 933-6 932-7 931-8 930-8 107s 930-2 929-3 928-4 927-4 926-5 1080 925-9 925-0 924-1 923-1 922-2 1085 921-7 920-7 919-8 9189 918-0 1090 917-4 916-5 915-6 914-7 913-8 1095 913-2 912-3 9114 9105 9096 1 1 00 909-1 908-2 907-3 906-4 ■ 905-4 1105 905-0 904-1 9032 902-3 901-4 mo 9009 900-0 899-1 898-2 897-3 "15 896.9 896-0 895-1 894-2 893-3 1120 81.2-9 892-0 891-1 890-2 889-3 1125 888-9 888-0 887-1 886-2 885-3 1130 885-0 884-1 883-2 882-3 881-4 "35 88i-i 880-2 879-3 878-4 877-5 1 140 877-2 876-3 875-4 874-6 873-7 THE ASS A V OF SItVMR. 215 Alloy by employing an Amount of Alloy always THE SAME Amount of Silver. SILVER. 5 6 7 8 9 10 995 'o 994-0 993 'o 992-0 991-0 990-0 990*0 989-0 988-1 987-1 986-1 985-1 9851 984-2 983-2 982-2 981-2 980-2 980-3 979-3 978-3 977-3 9764 975-4 975-5 974-5 973 5 972-5 971-6 970-6 970-7 969-8 968-8 967-8 966-8 965-8 966'o 965-0 964-1 963-1 962-1 961-2 961-3 960-4 959-4 958-4 9S7.-5 956-s 9567 955-8 954-8 953-8 952-9 951-9 952-1 9SI-2 950-2 949-3 9483 947-4 947-6 946-7 945-7 944-8 943-8 9429 943-1 9422 941-2 940-3 939-3 9384 938-7 937-7 936-8 935-8 934-9 9340 934-3 933-3 932-4 931-4 9305 929-6 929-9 929-0 928-0 927-1 926-2 9252 925-6 924-7 923-7 9228 921-9 920-9 921-3 920-4 919-4 918-5 917-6 916-7 9170 916-1 915-2 914-3 913-4 912-4 912-8 911-9 911 -0 910-1 909-2 908-3 908-7 907-8 906-8 905-9 905-0 9041 904-5 903-6 902-7 901-8 900-9 900-0 900-4 899-5 8986 897-7 8968 895-9 896-4 895-5 894-6 893-7 892-8 891-9 892-4 891 5 890-6 8897 888-8 8879 888-4 887-5 886-6 885-7 884-8 883-9 884-4 883-6 882-7 881-8 880-9 880-0 880-5 879-6 8788 877-9 877-0 876-1 876-7 875-8 8749 8740 873-1 872-3 872-8 871-9 8710 870-2 869-3 8684 it6 TH$: PHACTICAL ASSA YE-R. NITRATE OF We^ht of Assay in 1 2 3 4 Milligrs. "45 873-4 872-5 871-6 870-7 869-9 1150 8696 868-7 867-8 867-0 866-1 "55 865-8 864-9 864-1 863-2 862-3 1160 862-1 861-2 860-3 859-5 858-6 1165 858-4 857-5 856-6 855-8 854-9 1170 8547 853-8 853-0 852-1 851-3 "75 851-1 850-2 849-4 848-5 847-7 1 180 847-5 846-6 845-8 844-9 844-1 1185 843-9 843-0 842-2 841-3 840-5 1190 840-3 849-5 838-7 837-8 837-0 "95 8368 836-0 835-1 834-3 833-5 1200 833-3 832-5 831-7 830-8 830-0 1205 829-9 829-0 828-2 827-4 826-6 1210 826-4 825-6 824-8 824-0 823-1 1215 823-0 822-2 821-4 8206 819-7 1220 819-7 818-8 818-0 817-2 816-4 1225 816-3 815-5 814-7 813-9 813-1 1230 813-0 812-2 81 1 -4 810-6 809-8 1235 809-7 808-9 808-1 807-3 806-5 1240 806-5 805-6 804-8 804-0 803-2 124s 803-2 802-4 801 -6 800-8 800-0 1250 Soo'o 799-2 798-4 797-6 796-8 1255 796-8 7960 795 '2 794-4 793-6 1260 793-6 792-9 792-1 791-3 790-5 1265 790-5 789-7 788-9 788-1 787-3 1270 787-4 786-6 785-8 785-0 784-2 1275 784-3 783-5 782-7 782-0 781-2 1280 781-2 780-5 779-7 778-9 778-1 1285 778-2 777-4 776-6 775'9 775-1 1290 775'2 774-4 7736 772-9 772-1 129s 772-2 771-4 770-7 769-9 769-1 1300 769-1 768-5 ' 767-7 766-9 766-1 ^305 766-3 765-5 764-7 764-0 763-2 THE ASS A y OF SIL VER. 217 SILVER— < ontinued. 5 6 7 8 9 10 869-0 868-1 867-2 866-4 865-5 8646 865-2 864-3 863-5 862-6 861-7 860-9 861-5 86o-6 8597 858-9 858-0 857-1 857-8 856-9 856-0 855-2 854-3 853-4 8541 853-2 852-4 851-5 850-6 849-8 850-4 849-6 848-7 847-9 847-0 846-1 846-8 846-0 845-1 844-3 843-4 842-5 843-2 842-4 841-5 840-7 839-8 839-6 8397 838-8 838-0 837-1 836-3 835-4 836-1 835-3 834-5 833-6 832-8 831-9 832-6 831-8 8310 830-1 829-3 828-4 829-2 8283 827-5 826-7 825-8 825-0 825-7 824-9 824-1 823-2 822-4 821-6 822-3 821-5 820-7 819-8 819-0 818-2 818-9 818-1 817-3 816-5 815-6 814-8 815-6 814-7 813-9 813-1 812-3 811-5 812-2 811-4 8io-6 809-8 809-0 808-2 808-9 808-1 807-3 806-5 805-7 804-9 805-7 804-9 804-0 , 803-2 802 '4 801-6 802-4 801-6 800-8 800-0 799-2 798-4 799-2 798-4 797-6 796-8 796-0 795-2 7960 795'2 794-4 793-6 792-8 792-0 792-8 792-0 791-2 790-4 789-6 788-8 789-7 788-9 788-1 787-3 786-s 785-7 786-6 785-8 785-0 784-2 783-4 782-6 783-5 782-7 781-9 781-I 780-3 779-5 780-4 779-6 778-8 778-0 777-3 776-5 777-3 776-6 775'8 775"o 774-2 773-4 774-3 773'S 772-8 772-0 771-2 770-4 771-3 770-5 7698 769-0 768-2 767-4 7683 767-6 766-8 766-0 765-2 764-5 765-4 764-6 7638 763-1 762-3 761-5 762-4 761-7 760-9 760-1 759'4 758-6 3l8 THE PRACTICAL ASS AVER. NITRATE OF Weight of Assay in 1 2 3 4 Milligrs. 1310 763'4 762-6 761-8 7611 760-3 1315 760-5 7597 658-9 758-2 757-4^ 1320 7576 7568 756-1 755-3 754-5 1325 754"7 754'o 753-2 752-4 7517 1330 75i"9 75i'i 750-4 749-6 748-9 1335 749"! 748-3 747-6 746-8 746-1 1340 746-3 745 "5 744-8 744-0 743-3 1345 743 '5 742-7 742-0 741-3 740-5 1350 740-7 740-0 739'3 738-5 737-8 I3S5 738-0 737 '3 736-5 735-8 735-1 1360 73S'3 734-6 733-8 733-1 7324 1365 732-6 731-9 731-1 730-4 729-7 1370 729-9 729-2 728-5 7277 727-0 1375 727'3 726-5 7258 725-1 724-4 1380 724-6 723-9 723-2 722-5 721-7 1385 722-0 721-3 720-6 719-9 719-1 1390 7i9'4 718-7 718-0 717-3 716-5 1395 716-8 716-1 7i5"4 7147 714-0 1400 7i4'3 713-6 712-9 712-1 711-4 1405 711-7 711-0 710-3 709-6 708-9 1410 709-2 708-5 707-8 707-1 706-4 1415 706-7 706-0 705-3 704-6 703-9 1420 704-2 703-5 702-8 702-1 701-4 1425 701-8 701-0 700-3 699-6 698-9 143° 699'3 698-6 697-9 697-2 696-5 1435 696-9 696-2 695'5 694-8 694-1 1440 694-4 6937 693-1 692-4 691-7 1445 692*0 691-3 690-7 690-0 689-3 1450 689-7 689-0 688-3 6876 686-9 1455 687-3 7866 685-9 685-2 684-5 1460 684-9 684-2 683-6 682-9 682-2 1465 682-6 681-9 681-2 680 -6 679-9 1470 680-3 679-6 678-9 678-2 677-5 THE ASS A Y OF SILVER. 219 ^WM-ERr-CBtOinued. 5 6 7 8 9 10 " 7S9S 758-8 758-0 757-z 756-5 755-7 7566 755-9 755-1 754-4 753-6 752-8 753-8 753-0 752-3 751-5 750-8 750-0 750-9 750-2 749-4 748-7 747-9 747-2 748-1 747-4 746-6 745-9 745-1 744"4 745 '3 744-6 743-8 743-1 742-3 741-6 7425 741-8 741 -o 740-3 739-5 738-8 736-8 739-0- 738-3 737-S 736-8 736-1 73 7 -o 736-3 735-6 734-8 734-1 933-3 734-3 733-6 732-8 732-1 731-4 730-6 731-6 730-9 730-1 729-4 728-7 727-9 728-9 728-2 727-5 726-7 726-0- 725-3 726-3 725-5 724-8 . 724-1 723-4 7226 723-6 722-9 722-2 721-4 720-7 720-0 721-0 720-3 719-6 718-8 718-1 717-4 718-4 717-7 717-0 716-2 715-5 714-8 715-8 715-1 714-4 713-7 712-9 712-2 713-3 712-5 711-8 7II-I 710-4 709-7 710-7 710-0 709-3 708-6 707-9 707-1 708-2 707-5 7068 706-0 705-3 704-6 705-7 705-0 704-3 703-5 702-8 702-1 703-2 702-5 701-8 701-1 700-3 699-6 700-7 "700-0 699-3 698-6 6979 697-2 698-2 697-5 696-8 696-1 695-4 694-7 695-8 695-1 694-4 693-7 693-0 692-3 693-4 692-7 692 691-3 690 -6 689-9 6910 690-3 689-6 6889 688-2 687-5 688-6 687-9 687-2 686-5 685-8 685-1 686-2 685-5 684-8 684-1 683-4 682-8 683-8 683-2 682-5 681-8 681 -I 680-4 681-5 680-8 680-1 679-4. 678-8 678-1 679-2 678-5 6778 677-1 676-4 675-8 676-9 1 676-2 675-5 674-8 674:1 673-5 THE PRACTICAL ASSAYER. NITRATE OF Weight of Assay in 1 2 3 4 Milligrs. I47S 678-0 677-3 676-6 675-9 675-2 1480 6757 675-0 674-3 673-6 673-0 1485 673'4 672-7 672-0 671-4 670-7 1490 6711 670-5 669-8 669-1 668-5 1495 668-9 668-2 667-6 666-9 666-2 1500 666-7 666-0 665-3 664-7 664-0 1505 664-5 663-8 663-1 662-5 661-8 1510 662-3 661-6 660-9 660-3 659-6 1515 660-1 659-4 658-7 658-1 657-4 1520 657-9 657-2 656-6 655-9 655-3 1525 655-7 655-1 654-4 653-8 653-1 iS3«J 653-6 652-9 652-3 651-6 651-0 IS35 651-5 650-8 650-2 649-5 648-9 1540 649-4 648-7 648-0 647-4 646-7 IS4S 647-2 646-6 645-9 645-3 644-7 1550 645-2 644-5 643-9 643-2 642-6 ISS5 643-1 642-4 641-8 641-2 640-5 1560 641-0 640-4 639-7 639-1 638-5 1565 639-0 638-3 6377 637-1 636-4 157° 636-9 6363 635-7 635-0 634-4 1575 634-9 634-3 6336 633-0 632-4 1580 632-9 6323 631-6 631-0 630-4 1585 630-9 630-3 629-6 629-0 628-4 1590 628-9 628-3 627-7 , 627-0 626-4 159s 627-0 626-3 625-7 625-1 624-4 1600 625-0 624-4 623-7 923-1 622-5 1605 623-1 622-4 621-8 621-2 620-6 1610 621-1 620-5 619-9 619-2 6i8-6 1615 619-2 618-6 618-0 617-3 616-7 1620 617-3 616-7 6i6-o 615-4 614-8 1625 615-4 614-8 614-1 613-5 612-9 1630 613-5 612-9 612-3 611-7 61 1 -0 163s 611-6 61 1 -0 610-4 609-8 609-2 THE ASS A Y OF SILVER. BILVKR— continued. 5 6 7 8 g 10 674-6 673"9 673-2 .672-5 671-9 671-2 672-3 671-6 670-9 670-3 669-6 668-9 670-0 669-4 668-7 6680 667-3 6667 667-8 667-1 666-4 665-8 66S-J 664-4 665-5 6649 664-2 663-5 662-9 6622 663-3 662-7 662-0 661-3 660-7 66o-o 66I-I 660-5 659-8 659-1 658-5 657-8 658-9 658-3 657-6 656-9 656-3 -655-6 656-8 656-1 655-4 654-8 654-1 653-5 654-6 653-9 653-3 652-6 652-0 651-3 6S2"S 651-8 651-1 650-5 649-8 649-2 65o"3 649-7 649 648-4 647-7 647-1 648-2 647-6 646-9 646-2 645-6 644-9 646-1 645-4 644-8 644-2 643-5 642-9 644-0 643-4 642-7 642-1 641-4 640-8 641-9 641-3 640 -6 640-0 639-3 6387 6399 639-3 638-6 637-9 637-3 636-7 637-8 637-2 636-5 635-9 635-3 634-6 635-8 635'! 634-5 633-9 633-2 632-6 633;8 633-1 632-5 631-8 631-2 630-6 631-7 631-1 630-S 629'8 629-2 628-6 629-7 629-1 628-5 627-8 627-2 6266 627-8 627-1 626-5 625-9 625-2 624-6 625-8 62 5--2 624-5 623-9 6233 622-6 6238 623-2 622-6 621-9 621-3 620-7 621-9 621-2 620-6 620-0 619-4 618-7 619-9 619-3 618-7 6i8-i 617-4 6i6-i 6180 617-4 6i6-8 6r6-i 615-5 614-9 6id-i .615-5 614-9 614-2 613-6 613-0 6x4-2 613-6 613-0 612-3 611-7 611-1 612-^ 6II-7 611-1 610-5 6098 609-2 610-4 609-8 609-2 608-6 6080 607-4 6086 607-9 607-3 606-7 606-1 605-5 THE PRACTICAL ASS AVER. NITRATE OF Weight of Assay in 1 2 3 4 Milligrs. 1640 6098 609-1 608-5 607-9 607-3 1645 6079 607-3 606-7 606-1 605-5 1650 6o6'i 605-4 .604-8 604-2 603-6 16SS 604-2 603-6 603-0 602-4 601-8 1660 602-4 601-8 601 -2 600-6 600-0 1665 600-6 6000 599-4 598-8 598-2 1670 598-8 598-2 597-6 597-0 596-4 167s 597-0 596-4 595-8 595-2 594-6 1680 595-2 594-6 594-0 593-4 592-9 1685 593-5 592-9 592-3 591-7 59I-I 1690 591-7 591-1 590-S 589-9 589-3 169s 590-0 589-4 588-8 588-2 587-6 1700 588-2 587-6 587-1 586-5 585-9 170S 586-5 585-9 585-3 584-7 584-2 1710 584-8 584-2 583-6 583-0 58.2-5 1715 583-1 582-5 581-9 581-3 580-8 1720 581-4 580-8 580-2 5 7-9 -6 579-1 1725 579-7 579-1 578-5 578-0 577-4 1730 578-0 577-5 576-9 576-3 575-7 1735 576-4 575-8 575-2 574-6 574-1 1740 574-7 574-1 573-6 573-0 572-4 1745 S73-I 572-S 571-9 571-3 570-8 1750 571-4 570-9 570-3 569-7 569-1 1755 569-8 569-2 568-7 568-1 567-5 1760 568-2 567-6 567-0 566-S 565-9 1765 566-6 566*0 565-4 564-9 564-3 1770 565-0 564-4 563-8 563-3 562-7 1775 563-4 562-8 562-2 561-7 561-1 1780 561-8 561-2 560-7 560-1 559-5 1785 560-2 559-7 559-1 558-S 558-0 1790 558-7 558-1 557-5 557-0 556-4 179s 557-1 556-5 556-0 555-4 554-9 1800 555-6 555-5 554-4 553-9 553-3 THE ASSAY OF SILVER. 223 %\\N'S.'&.— continued. 6 6 7 8 9 10 6067 606-1 605-5 604-9 604-3 603-7 6049 604-3 603-6 603-0 602-4 601-8 603 602-4 601 -8 6012 6oo-6 6oo-o 60 1 2 600*6 600-0 5994 598-8 598-2 599"4 598-8 598-2 597'6 597-0 596-4 S97-6 597-0 596-4 595-8 595-2 594'6 595-8 595-2 594^6 594-0 593 4 592-8 594-0 593-4 592-8 592-2 591-6 591-0 5923 591-7 591-1 590-5 589-9 589-3 590-5 589-9 589-3 588-7 588-1 587-5 588-8 588-2 587-6 587-0 586-4 585-8 587-0 586-4 585-8 585-2 584-7 584-1 583 -s 584-7 584-1 583-5 582-9 582-3 585-6 583-0 582-4 581-8 581-2 580-6 581-9 581-3 580-7 580-1 579-5 578-9 580-2 579-6 579-0 578-4 577-8 577-3 578-5 577-9 577-3 576-7 576-2 575-6 576-8 576-2 575-6 575-1 574-5 573-9 57S-I 574-6 574-0 573-4 572-8 572-2 573-5 572-9 572-3 571-8 571-2 570-6 571-8 571-3 570-7 570-I 569-5 569-0 570-2 569-6 569-0 568-5 567-9 567-3 568-6 568-0 567-4 566-9 566-3 565-7 566-9 566-4 565-8 565-2 564-7 564-1 565-3 564-8 564-2 563-6 563-1 562-5 563-7 563-2 562-6 562-0 561-5 560-9 562-1 561*6 561-0 560-4 559-9 5593 560-6 560-0 559-4 558-9 558-3 557-7 559-0 558-4 557-9 557-3 556-7 556-2 557-4 556-9 556-3 555-7 555-2 554-6 555-9 555-3 554-7 554-2 553'6 553-1 554-3 553-8 553-2 552-6 552-1 551-5 552-8 552-2 551-7 551-1 550-6 550-O 224 THE PRACTICAL ASS AVER. NITRATE OF Weight of Assay in 1 2 3 4 MiUigrs. 1805 S54-0 553-5 552-9 552-3 551-8 1810 552'5 551-9 551-4 550-8 550-3 1815 SSi'o 550-4 549-9 549-3 548-8 1820 S49"4 548-9 548-3 547-8 547-2 1825 547-9 547-4 546-8 546-3 545 '7 1830 546-4 545-9 545-4 544-8 544-3 1835 545-0 544-4 543-9 543-3 542-8 1840 543-5 542-9 542-4 541-8 541-3 1845 5420 541-5 540-9 540-4 539"8 1850 540-5 540-0 539-5 538-9 538-4 1855 539-r 538-5 538-0 537-5 536-9 i860 537-6 537-1 536-6 536-0 535-5 1865 536-2 535-7 535-1 534-6 534-0 1870 534-8 534-2 533-7 533-2 532-6 1875 533-3 532-8 532-3 531-7 531-2 1880 531-9 531-4 530-8 530-3 529-8 1885 530-5 530-0 529-4 528-9 528-4 1890 529-1 528-6 528-0 527-5 527-0 189s 527-7 527-2 526-6 526-1 526'6 1900 5263 525-8 5253 524-7 524-2 i9°5 524-9 524-4 523-2 523-4 522-8 1910 523-6 523-0 522-5 522-0 521-5 1915 522-2 521-7 521-1 520-6 520-1 1920 520-8 520-3 5i9"8 519-3 518-7 1925 519-5 519-0 518-4 517-9 517-4 1930 StS-i 517-6 517-1 516-6 5161 193s 516-8 516-3 5i5'8 515-2 514-7 1940 515-5 514-9 514-4 513-9 S13-4 1945 6141 513-6 5i3'i 512-6 512-1 1950 512-8 512-3 511-8 511-3 510-8 I9SS 5"S 511-0 510-5 510-0 509-5 i960 510-2 509-7 509-2 508-7 508-2 1965 508-9 508-4 507-9 507-4 1 506-9 THE ASS A Y OF SILVER. 225 S I LVER — continued. 10 S5I--2 5497 548-2 5467 545-2 5427 542-2 S40-8 539 3 537-8 536-4 534-9 533-5 532-1 53°7 529-3 527-8 526-5 525-1 523-7 522-3 520-9 519-6 518-2 5t6-9 515-5 514-2 512-9 511-6 510-3 508-9 507-6 506-4 550-7 549-2 547-7 546-2 5447 543-2 5417 540-2 5387 537-3 535-8 534-4 5330 531-5 530-1 5287 527-3 525-9 524-5 523-2 521-8 520-4 519-1 517-7 516-4 515-0 513-7 512-4 511-0 509-7 508-4 507-1 50.5-8 550-1 548-6 547-1 545-6 544-1 542-6 S4I-I 539-7 538-2 536-8 535-3 533-9 532-4 531-0 529-6 528-2 526-8 525-4 524-0 522-6 521-3 519-9 518-5 517-2 515-8 514-5 513-2 S"-9 510-5 509-2 507-9 506-6 505-3 549-6 548-1 546-6 54S;i 543-6 542-1 540-6 539-1 5377 536-2 534-8 533-3 531-9 530-5 529-1 527-7 526-3 524-9 523-5 522-1 520-7 519-4 518-0 5167 515-3 514-0 5127 511-3 510-0 508-7 507-4 506-1 504-8 549-0 548-5 547-5 547-0 546-0 545-5 544-5 544-0 543-0 542-5 541-5 541-0 540-0 5395 5386 538-0 537-1 5366 535-7 53S-I 534-2 533-7 532-8 532-3 531-4 S30-8 5299 529-4 528-S 528-0 527-1 526-6 525-7 525-2 524-3 523-8 5230 522-4 521-6 521-0 520-2 519-7 518-8 518-3 517-S 517-0 516-1 515-6 514-8 514-3 513-5 512-9 512-1 511-6 5100 510-3 509-5 509-0 508-2 5077 506-9. 506-4 505-6 505-1 504-3 503-8 Q 226 THE PRACTICAL ASS A YER. NITRATE OF Weight of Assay in 1 2 3 4 Milligrs. 1970 507-6 507-1 506-6 506-1 505-7 I97S 506-3 505-8 505-3 504-8 504-3 1980 5°S'o 504-5 504-0 503-5 503-0 198s 503-8 503-3 502-8 502-3 501-8 1990 502-5 502-0 S01-5 501-0 500-5 199s 501-3 500-7 500-2 4997 499-2 2000 500-0 499-5 499-0 498-5 498-0 Tables for Determining the Standard of any Silver approximately containing COMMON Weight of Assay in 1 2 3 4 Milligrs. 1000 looo-o 1005 995-0 996-0 997-0 998-0 999 "o lOIO 990-1 991-1 992-1 993-1 994-1 1015 985-2 986-2 987-2 988-2 989-1 1020 980-4 981-5 982-4 9833 984-3 1025 975-6 976-6 977-6 978-5 979-5 1030 970-9 971-8 972-8 973-8 974-8 1035 966-2 967-1 968-1 969-1 970-0 1040 961-5 962-5 963-5 964-4 965-4 1 04s 956-9 957-9 958-8 9598 960-8 1050 952-4 953-3 954-3 955-2 956-2 1055 947-9 948-8 949-8 9507 9517 THE ASSAY OF SILVER. 227 SILVER— ««ftKK«y. 5 6 7 8 ■ 10 SoS'i 504-6 504-1 . 503-5 503-0 500-5 503-8 503-3 502-8 502-3 501-8 501-3 502-5 509-0 501-5 501-0 500-5 500-0 501-3 500-8 500-2 499-7 499-2 498-7 500-0 499-5 499-0 498-5 498-0 497-s 498-7 498-2 497-7 497-2 496-7 496-2 4975 497-0 496 5 496-0 495-5 495-0 Alloy by employing an Amount of Alloy always the same amount of silver. SALT. 5 '6 7 8 9 10 looo-o 9950 996-0 997-0 998-0 999-0 looo-o 990-1 991-1 992-1 993-1 994-1 -995-1 985-3 986-3 987-2 988-2 989-2 990-2 980-5 981 5 982-4 983-4 984-4 985-4 975-7 976-7 977-7 978-6 979-6 980-6 971-0 972-0 972-9 973'9 974-9 975-8 966-3 967-3 968-3 9692 970-2 97I-I 961-7 962-7 963-6 964-6 965-5 966-5 957-1 958-1 9590 960-0 960-9 961-9 952-6 953-S 954-5 955-4 956-4 957-3 228 THE PRACTICAL ASS A YER. COMMON Weight of Assay in ■ 1 2 3 4 Milligrs. 1060 943"4 944-3 945-3 946-2 947-2 1065 939'9 939-9 940-8 941-8 942-7 1070 9346 935-5 936-4 937-4 938-3 107s 930-2 931-2 932-1 933-0 933-9 1080 925'9 9268 927-8 928-7 929-6 1085 921-7 922-6 923-5 924-4 925-3 1090 91 7 '4 918-3 919-3 920-2 921-1 109s 913-2 914-2 915-1 9160 917-0 IIOO 909-1 910-0 910-9 911-8 912-7 II05 905-0 905-9 906-8 907-7 908-6 IIIO 900-9 901-8 902-7 903-6 904-5 "I5 896-9 897-8 898-6 899-5 900-4 II20 892-9 893-7 894-6 895-5 896-4 1125 888-9 889-8 890-7 891-6 892-4 II30 885-0 885-8 886-7 887-6 888-5 "35 88I-I 881-9 882-8 883-7 884-6 ii'40 877-2 •878-1 878-9 879-8 880-7 "45 873-4 874-2 875-1 876-0 876-9 1150 869-6 870-4 871-3 872-2 873-0 "55 865-8 866-7 867-4 868-4 869-3 1160 862-1 862-9 863-8 864-7 865-5 1165 858-4 859-2 86o-i 860-9 861-8 1170 854-7 855-6 856-4 857-3 858-1 "75 851-1 851-9 852-8 853-6 854-5 1 180 847-5 848-3 849-2 850-0 850-8 1185 843-9 844-7 845-6 846-4 847-3 1 190 840-3 841-2 842-0 842-9 843-7 "95 8368 837-7 838-5 839-3 840-2 1200 833-3 834-2 835-0 835-8 836-7 1205 829-9 8307 831 -5 832-4 833-2 1210 826-4 827-3 828-1 828-9 829-7 1215 823-0 823-9 824-7 825-5 826-3 1220 819-7 820-5 821-3 822-1 822-9 THE ASSAY OF SILVER. 229 ^MJY—contimted. S 6 7 8 9 10 9481 949-1 950.0 950-9 951-9 552-8 9437 944-6 945 -5 946-5 947-4 948-4 939-3 940-2 941 -I 942-1 943-0 943-9 934-9 935-8 936-7 937-7 938-6 939-5 930-6 93I-S 932-4 933-3 934-3 935-2 926-3 927-2 928-1 929-0 930-0 930-9 922-0 922-9 923-8 924.8 925-7 926-6 917-8 918-7 919-6 920-5 921-5 922-4 913-6 914-5 915-4 916-4 917-3 918-2 909'S 910-4 911-3 912-2 913-1 914-0 9°5'4 906-3 907-2 908-1 909-0 909-9 901-3 902 -2 903-1 904-0 904-9 . 905.8 897-3 898-2 899-1 900-0 900-9 901-8 893-3 894-2 895-1 896-0 896-9 897-8 889-4 890-3 891-1 892-0 892-9 893-8 885-5 886-3 887-2 888.1 889-0 889-9 88i-6 882-S 883-3 88412 885-1 886-0 877-7 878-6 879-S 880-3 88 1 -2 882-1 873-9 874-8 875-7 876-5 877-4 878-3 870-1 871-0 871-9 872-7 873-6 874-5 866-4 867-2 868-1 869-0 869-8 870-7 862-7 863-5 864-4 865-2 866-1 866-9 859-0 859-8 860-7 861-5 862-4 863-2 855-3 856-2 857-0 857-9 858-7 859-6 851-7 852-5 853-4 854-2 85S-1 855-9 848-1 848-9 849-8 ■ 850-6' 851-S 852-3 844-5 845-4 846-2 847-1 847-9 848-7 841-0 841-8 842-7 843-5 844-3 845-2 837-S 838-3 839-2 840-0 840-8 841-7 834-0 834-8 835-7 836.S 837-3 838-2 830-6 831-4 832-2 833-1 833-9 834-7 827-2 828-0 828-8 829-6 830-4 831-3 823-8 824-6 825-4 8262 827-0 827-9 230 THE PRACTICAL ASS A YER. COMMON Weight of Assay in 1 2 3 4 Milligrs. 1225 816-3 817-1 818-0 818-8 819-6 1230 8130 813-8 814-6 815-4 816-3 1235 8097 810-5 811-3 812-1 813-0 1240 806-5 807-3 8o8-i 808-9 809-7 1245 803-2 804-0 804-8 805-6 806-4 1250 800-0 800-8 801-6 802-4 803-2 125s 796-8 797-6 798-4 799-2 800-0 1260 793"6 794-4 795-2 796-0 796-8 1265 7 9° '5 791-3 792-1 792-9 793-7 1270 787-4 788-2 789-0 789-8 790-5 127s 784-3 785-1 785-9 786-7 787-4 1280 781-2 782-0 782-8 783-6 784-4 1285 778-2 779-0 779-8 780-5 781-3 1290 775-2 776-0 776-7 777-5 778-3 1295 772-2 773-0 773-7 774-S 775-3 1300 769-2 770-0 770-8 771-5 772-3 1305 766-3 767-0 767-8 768-6 769-3 1310 763-4 764-1 764-9 765-6 766-4 1315 760-s 761-2 762-0 762-7 763-5 1320 757-6 758-3 759-1 759-8 760-6 1325 754-7 755-5 756-2 757-° 757-7 1330 751-9 752-6 753-4 754-r 754-9 1335 749-1 749-8 750-6 751-3 752-1 1340 746-3 747-0 747-8 748-5 749-2 1345 743-5 744-2 745-0 745-7 746-5 1350 740-7 741-5 ■ 742-2 743-0 743-7 1355 738-0 738-7 739-5 740-2 741-0 1360 735-3 736-0 736-8 737-5 738-2 1365 732-6 733-3 734-1 734-8 735-5 1370 729-9 730-7 731-4 732-1 732-8 1375 727-3 728-0 728-7 729-4 730-2 1380 724-6 725-4 726-1 7268 727-5 1385 722-0 722-7 723-S 724-2 724-9 THE ASSAY OF SILVER. 231 ^kVl—contintud. 5 • 6 7 8 9 10 820-4 821-2 822-0 82 2 9 823-7 824-5 817-1 817-9 818-7 819-5 820-3 821-1 813-8 814-6 815-4 816-2 817-0 817-8 810-5 811-3 8l2-I 812-9 813-7 814-5 807-2 8o8-b 808-8 809-6 810-4 8II-2 804-0 804-8 8056 806-4 807-2 808 -o 800-8 801 -6 802-4 803-2 804-0 804-8 797-6 798-4 799-2 800 -o 800 -8 801 -6 794-5 795'3 796-0 7968 797-6 798-4 7913 792-1 792-9 793-7 794-S 795-3 788-2 789-0 789-8 790-6 791-4 792-2 785-2 786-0 786-7 787-5 788-3 789-1 782-1 782-9 783-7 784-4 785-2 7860 779-1 779-8 780-6 781-4 782-2 782-9 776-1 776-8 777-6 778-4 779-1 779-9 7731 773-8 774-6 775-4 776-1 776-9 770-1 770-9 771-6 772-4 773-2 773-9 767-2 767-9 768-7 769-5 770-2 771-0 764-3 765-0 765-8 766-5 767-3 768-1 761-4 762-1 7629 763-6 764-4 765-2 758-S T59'2 760-0 760-7 761-5 762-3 7S5'6 756-4 757-1 757-9 758-6 759-4 752-8 753'6 754-3 7S5-I 755-8 756-6 750-0 75°7 751-5 752-2 753-0 753-7 .747-2 748-0 748-7 749-4 750-2 750-9 744-4 745 '2 745-9 746-7 747-4 748-1 741-7 742-4 743-2 743-9 744-6 745-4 739"° 7397 740-4 741-2 741-9 742-6 736-3 737-0 737-7 738-5 739-2 739-9 733"6 734-3 735-0 735-8 736-5 737-2 730'9 73i'6 732-4 733-2 733-8 734-5 728-3 729-0 729-7 730-4 731-2 731-9 725-6 726-3 727-1 727-8 728-s 729-2 232 THE PRACTICAL ASSAYER. COMMON Weight of Assay in 1 2 3 • 4 Milligrs. 1390 7i9"4 720-1 720-9 721-6 722-3 1395 716-8 717-6 718-3 719-0 719-7 1400 7143 715-0 715-7 7164- 717-1 1405 7117 712-5 713-2 713-9 714-6 1410 709-2 709-9 710-6 7" -3 7121 I415 706-7 707-4 708-1 708-8 709-5 1420 704-2 704-9 705-6 706-3 707-0 1425 701-8 702-5 703-2 703-9 704-6 143° 6993 700-0 700-7 701-4 702-1 143s 696-9 697-6 698-3 698-9 699 -6 1440 694-4 695-1 695-8 696-5 697-2 1445 692 692-7 693-4 694-1 694-8 145° 689-7 690-3 691-0 691-7 692-4 I4SS 687-3 688-0 688-7 689-3 690-0 1460 684-9 685-6 686-3 687-0 687-7 1465 6826 683-3 684-0 684-6 685-3 1470 680-3 680-9 681-6 682-3 683-0 1475 678-0 678-6 679-3 680-0 680-7 1480 6757 676-3 677-0 677-7 678-4 - 1485 673-4 674-1 . 674-7 675-4 676-1 1490 671-1 671-8 672-5 673-1 673-8 1495 668-9 669-6 670-2 670-9 671-6 1500 666-7 667-3 668-0 668-7 669-3 1505 664-5 665-1 665-8 666-4 667-1 1510 662-3 662-9 6636 664-2 664-9 1515 660-1 6607 661-4 662-0 662-7 1520 657-9 658-5 659-2 659-9 660-5 1525 655-7 656-4 6570 657-7 658-4 1530 6536 654-2 654-9 655-6 . 656-2 IS3S 651-5 652-1 652-8 653-4 654-1 1540 ' 649-4 650-0 650-6 651-3 651-9 1 545 647-2 647-9 648-5 649-2 649-8 »55o 645-2 645:8 646 4 647-1 647-7 THE ASS A Y OF SILVER. 233 SALT — continued. 5 6 7 8 g 10 723-0 723-7 724-5 725-2 725-9 726-6 720-4 72I'I 721-9 722-6 723-3 724-0 717-9 718-6 719-3 720-0 720-7 721-4 715-3 7160 716-7 717-4 718-1 718-9 712-8 7I3-S 714-2 714-9 715-6 •716-3 710-2 710-9 711-7 712-4 713-1 713-8 707-7 708-4 709-2 709-9 710-6 711-3 705-3 706-0 706-7 707-4 708-1 708-8 702-8 703-5 704-2 704-9 - 705-6 706-3 700-3 701-0 701-7 702-4 703-1 703-8 697-9 698-6 699-3 700-0 700-7 701-4 695-5 696-2 696-9 697-6 698-3 699-0 693-1 693-8 694-5 695-2 695-9 696-6 690-7 691-4 692-1 6928 693-5 694-2 688-4 689-0 689-7 690-4 6911 691-8 686-0 686-7 687-4 688-0 688-7 689-4 683-7 684-3 685-0 685-7 686-4 687-1 681-4 682-0 682-7 683-4 684-1 684-7 679-1 679-7 680-4 681-1 681-8 682-4 676-8 677-4 678-1 678-8 679-5 680-1 674-5 675-2 675-8 676-5 677-2 677-8 672-2 672-9 6736 674-2 674-9 675-6 6700 670-7 671-3 6720 672-7 673-3 667-8 668-4 669-1 669-8 670-4 6711 665-6 666-2 666-9 667-5 668-2 668-7 663-4 664-0 664-7 665-3 666-0 666-7 661-2 661-8 662-5 663-2 663-8 664-5 659-0 659-7 660-3 661-0 66 1 -6 662-3 656-9 657-5 658-2 658-8 659-5 660-1 654-7 655-4 656-0 656-7 657-3 658-0 652 -6 653-2 653-9 654-5 655-2 655-8 650-5 651-1 651-8 652-4 653-1 653-7 648-4 649-0 649-7 650-3 651-0 651-6 234 THE PRACTICAL ASSA YER. COMMON Weight of Assay in 1 2 3 4 Milligrs. iSSS 643' I 643-7 644-4 645-0 645-7 1560 641 "o 641-7 642-3 642-9 643-6 1565 639'o 639-6 640-3 640-9 641-5 1570 6369 637-6 638-2 6388 639-5 1575 634-9 635-6 636-2 636-8 637-5 1580 632-9 633-5 634-2 634-8 635-4 1585 630-9 631-5 632-2 632-8 633-4 1590 628-9 629-6 630-2 630-8 631-4 1595 627-0 627-6 628-2 628-8 629-5 1600 625-0 625-6 626-2 626-9 627-5 1605 623-1 623-7 624-3 624-9 625-5 I6I0 621-1 621-7 622-4 623-0 623-6 1615 6ig-2 619-8 620-4 621-0 621-7 1620 617-3 617-9 618-5 619-I 619-7 1625 615-4 616-0 6i6-6 617-2 617-8 1630 613-5 614-1 614-7 615-3 615-9 163s 611-6 612-2 6i2-8 613-5 614-1 1640 609-8 610-4 61 1 -0 6ii-6' 612-2 1645 607-9 608-5 609-1 609-7 610-3 1650 606-1 606-7 607-3 607-9 608-5 1655 604-2 604-8 605-4 606-0 606-6 1660 602-4 603-0 603-6 604-2 604-8 1665 600-6 601-2 601-8 602-4 6030 1670 598-8 599-4 600-0 600-6 601-2 1675 597-0 597-6 598-2 598-8 599-4 1680 595-2 595-8 596-4 597-0 597-6 1685 593-5 594-1 594-7 595-2 595-8 i6go 591-7 592-3 592-9 593-S 594-1 1695 590-0 590-6 591-1 591-7 592-3 1700 588-2 588-8 589-4 590-0 590-6 1705 586-S 587-1 587-7 588-3 588-9 1710 584-8 585-4 586-0 586-5 587-1 1715 583-1 583-7 584-3 584-8 585-4 THE ASS A Y OF SILVER. 235 SALT — continued. 6 6 7 8 9 10 6463 646-9 647-6 648-2 648-9 649-5 644-2 644-9 645-5 646-1 646-8 647-4 642-2 642-8 643-4 644-1 6447 645-4 640-1 . 640-8 641-4 642-0 642-7 643-3 638-1 638-7 639-4 640-0 6406 641-3 636-1 636-7 637-3 638-0 6386 639-2 634-1 634-7 635-3 6360 636-6 637-2 632-1 632-7 633-3 634-0 6346 635-2 630-1 630-7 631-3 632-0 632 -6 633-2 628-1 628-7 629-4 630-0 630-6 631-2 626-2 6268 627-4 628-0 628-7 629-g 624-2 624-8 625-5 626-1 ■ 626-7 627-3 622-3 6229 623-5 624-1 624-8 625-4 620-4 621-0 62 1 -6 622-2 622-8 623.5 618-5 619-I 619-7 620-3 620-9 621-5 616-6 617-2 617-8 618-4 619-0 619-6 6147 615-3 615-9 616-5 617-1 617-7 61Z-8 613-4 614-0 614-6 615-2 615-8 610-9 611-5 612-2 612-8 613-4 614-0 609-1 609-7 610-3 610-9 611-5 612-1 607-2 607-8 608-5 609-1 609-7 6103 605-4 606-0 606-6 607-2 607-8 608-4 6036 604-2 604-8 605-4 606-0 606-6 601 -8 602-4 603-0 603-6 604-2 604-8 600 -o 600-6 601-2 601-8 602-4 603-0 598-2 598-8 599-4 600-0 600-6 601-2 596-4 597-0 597-6 598-2 598-9 599-4 594-7 595-3 595-9 596-4 597-0 597-6 592-9 593-5 594-1 594-7 595-3 595-9 591-2 591-8 592-3 592-9 593-5 . S94-I 589-4 590-0 590-6 591-2 591-8 592-4 587-7 588-3 588-9 589-5 590-1 590-6 586-0 586-6 587-2 587-8 588-3 588-9 236 THE PRACTICAL ASSAYER. COMMON Weight of Assay in 1 2 3 4 MUligrs. 1720 581-4 582-0 582-6 583-1 583-7 1725 5797 580-3 580-9 581-4 582-0 1730 578-0 578-6 579-2 579-8 580-3 173s 576-4 576-9 577-5 578-1 578-7 1740 574-7 575-3 575-9 576-4 577-0 1745 573-1 573-6 574-2 574-8 575-4 1750 571-4 572-0 572-6 573-1 573-7 I7S5 569-8 570-4 570-9 571-5 572-1 1760 568-2 568-7 569-3 569-9 570-4 1765 5666 567-1 567-7 568-3 568-8 1770 565-° 565-5 566-1 566-7 567-2 1775 563-4 563-9 564-5 565-1 565-6 1780 561-8 562-4 562-9 563-5 564-0 178s 560-2 560-8 561-3 561-9 562-5 1790 558-7 559-2 559-8 560-3 560-9 179s 557-1 557-7 558-2 558-8 559-3 1800 555-6 556-1 556-7 557-2 557-8 1805 554-0 554-6 555-1 555-7 556-2 1810 552-5 553-0 553-6 554-1 554-7 1815 551-0 551-5 552-1 552-6 553-2 1820 549-4 550-0 550-5 551-1 551-6 1825 547-9 548-5 549-0 549-6 550-1 1830 546-4 547 -o 547-5 548-1 548-6 1835 545-0 545-5 546-0 546-6 547-1 1840 543-5 544-0 544-6 545-1 545-6 184s 542-0 542-S 543-1 543-6 544-2 1850 540-5 541-1 541-6 542-2 542-7 1855 539-1 539-6 540-2 540-7 541-2 i860 537-6 538-2 538-7 539-2 539-8 1865 536-2 536-7 537-3 537-8 538-3 1870 534-8 535-3 535-8 536-4 536-9 1875 1880 533-3 533-9 534-4 534-9 535-5 531-9 532-4 533-0 533-5 534-0 THE ASSAY OF SILVER. 237 S ALT — continued. 584-3 584-9 582-6 583-2 580-9 581-5 579-2 579-8 577-6 578-2 575-9 576-5 574-3 574-9 572-6 573-2 571 -0 S7I-6 569-4 570-0 567-8 568-4 566-2 566-8 564-6 565-2 563-0 563-6 561-4 562-0 559-9 560-4 558-3 558-9 556-8 557-3 5SS-2 555-8 553-7 554-3 552-2 552-7 550-7 551-2 549-2 549-7 547-7 548-2 546-2 546-7 544-7 545-3 543-2 543-8 541-8 542-3 540-3 540-9 538-9 539-4 537-4 538-0 536-0 536-5 534-6 535-1 585-5 586-0 583-8 584-3 582-1 582-7 580-4 58 1 '0 578-7 579-3 577-1 577-6 575-4 576-0 573-8 574-4 572-2 572-7 570-5 S7I-I 568-9 569-5 567-3 567-9 565-7 566-3 564-1 564-7 562-6 563-1 561-0 561 -6 559-4 560-0 557-9 558-4 556-3 556-9 554-8 555-4 553-3 553-8 551-8 552-3 550-3 550-8 548-8 549-3 547-3 547-8 545-8 546-3 544-3 544-9 542-9 543-4 541-4 541-9 539-9 540-5 538-5 539-0 S37-I 537-6 535-6 536-2 10 586 --6 587-2 584-9 585-5 583-2 583-8 581-6. 582-1 579-9 580-S 578-2 578-8 576-6 577-1 574-9 575-5 573-3 ^ 573-9 571-7 572-2 570-I 570-6 568-4 569-0 566-8 567-4 565-3 565-8 563-7 564-2 562-1 562-7 560-6 561-1 559-0 559-6 557-5 558-0 555-9 556-5 554-4 554-9 552-9 553-4 551-4 55r-9 549-9 55*4 548-4 548-9 546-9 547-4 545-4 545-9 543-9 544-5 542-5 543-0 541 -0 541-S 539-6 540-I 538-1 538-7 536-7 537-2 ■238 THi: PRACTICAL ASS A YER. COMMON Weight of Assay in 1 2 3 4 Milligrs. 1885 S3o'5 531-0 531-6 532-1 532-6 1890 529'! 529-6 530-2 530-7 531-2 189s 5277 528-2 528-8 529-3 5298 1900 526-3 526-8 527-4 527-9 528-4 1 90s 524-9 525-4 526-0 526-5 527-0 1910 523-6 524-1 524-6 525-1 525-6 1915 522-2 522-7 523-2 523-8 524-3 1920 5208 521-3 521-9 522-4 522-9 1925 519-5 520-0 520-5 521-0 521-6 1930 518-1 518-6 519-2 519-7 520-2 1935 516-8 517-3 517-8 518-3 518-9 1940 515-5 516-0 516-5 517-0 S17-5 194s 514-1 514-6 515-2 515-7 516-2 1950 512-8 513-3 513-8 514-4 514-9 1955 511-5 512-0 512-5 513-0 513-5 i960 510-2 510-7 511-2 511-7 512-2 1965 508-9 509-4 509-9 510-4 510-9 1970 507-6 508-1 508-6 509-1 509-6 1975 506-3 506-8 507-3 507-8 508-3 1980 505-0 505-6 506-1 506-6 507-1 1985 503-8 504-3 504-8 505-3 505-8 1990 502-5 503-0 503-5 504-0 504-S 199s 501-3 501-8 502-3 502-8 503-3 2000 500-0 500-5 501-0 501-5 502-0 THE ASSAY OF SILVER. 239 SALT — continued. 533'2 5317 530"3 528-9 5276 526'2 524-8 S23"4 522-1 520-7 5i9"4 518-0 5167 5i5'4 Si4"i 512-8 S"'4 510-1 508-9 507-6 506-3 S°5-° S°3"8 502"S 5337 S32"3 530"9 529-5 528-1 526-7 525*3 524-0 522-6 521-2 5199 518-6 517-2 515-9 514-6 513-3 512-0 5107 509-4 508-1 506-8 505-5 504-3 503-0 534-2 532-8 531-4 530-0 528-6 527-2 525-8 524-5 523-1 521-8 520-4 S19-1 5177 516-4 515-1 S13-8 512-5 511-2 509-9 508-6 507-3 506-0 504-8 503-5 - 9 10 ■534-7 533-3 531-9 530-5 529-1 5277 526-4 525-0 523-6 522-3 520-9 519-6 518-2 516-9 515-6 514-3 513-0 S"7 510-4 509-1 507-8 506.5 505-3 504-0 535-3 533-9 532-4 531-0 5297 528-3 526-9 525-5 524-2 522-8 521-4 520-1 518-8 517-4 516-1 514-8 513-5 512-2 510-9 509-6 508-3 507-0 505-8 504-5 535-8 534-4 533-0 531-6 530-2 528-8 527-4 526-0 524-7 523-3 522-0 520-6 519-3 517-9 516-6 515-3 514-0 5127 511-4 510-1 508-8 ■ 507-5 506-3 505-0 ASSAY OF GOLD OR SILVER. Assay Table, showing the Amount of Gold or Silver, IN Ounces, Pennyweights, and Grains, contained IN A Ton of -Ore, &c., from the weight of Metal OBTAINED IN AN ASSAY OF 300 GRAINS OF MINERAL. If 200 Grains of One Ton of Ore. If 200 Grains of One Ton of Ore Ore give of will yield of Ore give of will yield of FINE METAL FINE METAL FINE METAL FINE METAL Gr. On. Dwts. Grs. Gr. Oz. Dwts Cw. "OOI 3 6 •028 4 II II •002 6 12 •029 4 14 17 •003 9 19 •030 4 18 •004 13 I •031 s I 6 ■005 16 8 •032 5 4 12 ■006 19 14 '°IZ 5 7 19 •007 2 20 ■034 s II I •008 6 3 •03 s 5 14 8 '009 9 9 •036 5 17 14 •010 12 6 ■037 6 20 •on IS 22 •038 6 4 3 •012 19 4 •039 6 7 9 •013 2 2 II •040 6 10 16 •014 2 s 17 ■041 6 13 22 ■°is 2 9 •042- 6 17 4 •016 2 12 6 ■043 II •017 2 15 12 ■044 ' 3 17 •018 2 18 19 ■045 7 •019 3 2 I •046 10 6 ■020 3 5 8 •047 13 12 •021 3 8 14 •048 16 19 •022 3 II 20 •049 8 I •023 3 15 3 •050 8 3 8 .024 3 18 9 ■°5i 8 6 14 •025 4 I 16 •052 8 9 20 •026 4 4 22 •053 8 13 3 •027 4 8 4 ■054 8 16 9 ASSAY OF GOLD OR SILVER. 241 If 200 Grains of One Ton of Ore If 200 Grains of One Ton of Ore Ore give of will yield of Ore give of Will yield of FINE METAL FINE METAL FINE METAL FINE METAL Gr. Cs. DwU. Grs. Gr. Oz. Dwts. Grs. •05 s 8 19 16 •091 14 17 6 •056 9 2 22 •092 IS 12 ■057 9 6 4 •093 IS 3 19 •058 9 -9 II •094 IS 7 I •059 9 12 17 •09s IS 10 8 •060 9 16 •096 15 13 14 •061 9 19 6 •097 IS 16 20 •062 10 2 12 •098 16 3 •063 10 S 19 •099 16 3 9 •064 10 9 I '100 16 6 16 •06 s 10 12 8 •loi 16 9 22 •066 10 15 14 •102 16 13 4 •067 10 18 20 •103 16 16 II . •068 11 2 3 •104 16 19 17 ■069 II 5 9 •105 17 3 •070 II 8 16 •106 17 6 6 •071 II II 22 •107 17 9 12 •072 II 15 4 •108 17 12 19 ■073 II 18 II •109 17 16 I ■074 12 I 17 ■*io 17 19 8 •07s 12 S •III 18 2 14 •076 12 8 6 •112 18 5 20 •077 12 II 12 •"3 18 9 3 •078 12 14 19 •114 18 12 9 •079, 12 18 I •"S 18 IS 16 •080 13 I 8 •116 18 18 22 ■081 13 4 14 •117 19 2 4 ■082 13 7 20 •118 19 s II •083 13 II 3 •119 19 8 17 •084 13 14 9 •120 19 12 6 •085 13 17 16 •121 19 IS 6 •086 14 22 •122 19 18 12 •087 14 4 4 •123 20 I 19 •088 14 7 ii •124 20 5 I ■089 14 10 *7, •I2S 20 8- 8 •090 14 14 •126 20 II 14 242 THE PRACTICAL ASS AVER. If 200 Grains of One Ton of Ore Ore give of will yield of FINE METAL FINE METAL Gr. Oz. JDwts. Grs. ■127 20 14 20 •128 20 18 3 ■129 21 I 9 ■130 21 4 16 •131 21 7 22 •132 21 II 4 ■13^ 21 14 II •134 21 17 17 ■135 22 I O •136 22 4 6 ■137 22 7 12 ■138 22 iO 19 ■139 22 14 I •140 22 17 8 •141 23 o 14 •142 23 3 20 • ■'■43 23 7 3 •144 23 10 9 ■145 23 13 16 ■146 23 16 22 •147 24 o 4 •148 24 3 II ■149 24 6 17 •150 24 10 o ■I Si 24 13 6 •152 24 16 12 •153 24 19 19 •154 25 3 I •iSS 25 6 8 ■156 25 9 14 ■157 25 12 20 ■158 25 16 3 •159 25 19 9 ■160 26 2 16 ■161 26 5 22 ■162 26 9 4 If 200 Grains of One Ton of Ore Ore give of vf ill yield of FINE METAL FINE METAL Gr. Oz. Dwls. Grs. •163 26 12 II •164 26 15 17 ■165 26 19 o ■166 27 2 6 •167 27 5 12 •168 27 8 19 ■169 27 12 I ■170 27 15 8 •171 27 18 14 ■172 28 I 20 ■173 28 5 3 ■174 28 8 9 •175 28 II 16 ■176 28 14 22 •177 28 18 4 ■178 29 I II ■179 29 4 17 ■180 29 8 o •181 29 II 6 •182 29 14 _ 12 •183 29 17 19 •184 30 I I •185 30 4 8 •186 30 7 14 •187 30 10 20 •188 30 14 3 •189 30 17 9 ■190 31 o 16 •191 31 3 22 ■192 31 7 4 •193 31 10 II 194 31 13 17 • ■195 31 17 o •196 32 o 6 ,■197 32 3 12 •198 32 6 19 ASSAY OF GOLD OR SILVER. 243 If 200 Grains of One Ton of Ore If 200 Grains of One Ton of Ore Ore give of will yield of Ore give of will yield of FINE METAL FINE METAL FINK METAL FINE METAL Gr. Oz. Dwts Grs. Gr. Oz. Dwts. Grs. •199 32 10 I ■235 38 7 16 ■200 32 13 8 •236 38 10 22 •201 32 16 14 •237 38 14 4 ■202 32 19 20 ■238 38 17 II •203 Zl 3 3 •239 39 17 ■204 33 6 9 •240 39 4 •205 33 9 16 •241 39 7 6 •206 33 12 22 •242 39 10 12 •207 33 16 4 •243 39 13 18 •208 33 19 II •244 39 17 I •209 34 2 n •245 40 8 •210 34 6 •246 ■ 40 3 14 •211 34 9 6 ■247 40 6 20 •212 34 12 12 •248 40 10 3 •213 34 15 19 •249 40 13 9 •214 34 19 I •250 40 16 16 •2IS 35 2 8 •251 40 19 22 •216 35 5 14 •252 41 3 4 .•217 35 8 20 •253 41 6 II •218 35 12 3 ■254 41 9 17 •219 35 IS 9 •255 41 13 •220 35 18 16 •256 41 16 6 •221 36 I 22 •257 41 19 12 ■222 36 5 4 ■258 42 2 19 •223 36 8 II •259 42 6 I •224 36- II 17 •260 42 9 8 •225 36 IS •261 42 12 14 •226 36 18 6 •262 42 IS 20 •227 37 I 12 •263 42 19 3 •228 37 4 19 •264 43 2 9 •229 37 8 I •265 43 s 16 •230 37 II 8 ■266 43 8 22 •231 37 14 14 •267 43 12 4 -232 37 17 20 •268 43 15 II ■233 38 I 3 •269 43 18 17 •234 38 4 9 ■270 44 2 244 THE PRACTICAL ASSAYER. If 200 Grains of One Ton of Ore Ore give of will yield of FINE METAL FINE METAL Gr. On. Dwts. Grs. •271 44 5 6 '•272 44 8 12 ■273 44 II 19 ■274 44 15 I ■275 44 18 8 •276 45 1 14 ■277 45 4 20 •278 45 8 3 •279 45 II 9 ■280 45 14 16 •281 45 17 22 ■282 46 I 4 ■283 46 4 ir •284 46 7 17 ■285 46 II o •286 46 14 6 •287 46 17 12 •288 47 o 19 •289 47 4 I •290 47 7 8 •291 47 10 14 •292 47 13 20 ■293 47 17 3 •294 48 o 9 •29s 48 3 16 •296 48 6 22 ■297 48 10 4 •298 48 13 II ■299 48 16 17 ■300 49 o o "3°i 49 3 6 •302 49 6 12 ■303 49 9 19 ■304 49 13 I •305 49 16 8 •306 49 19 14 I If 200 Grains of One Ton of Ore Ore give of will yield of FINE METAL FINE METAL Gr. Oz. Dwts. Grs. ■3°7 ^ 50 2 20 •308 S° 6 3 •309 50 9 9 •310 50 12 16 •311 50 15 22 •312 50 19 4 ■313 SI 2 II ■314 51 5 17 ■315 51 9 o •316 51 12 6 ■ai7 51 15 12 •318 51 18 19 •319 52 2 I ■320 52 5 8 ■321 52 8 14 ■322 52 II 20 ■323 52 15 3 •324 52 18 9 ■325 S3 I 16 ■326 S3 4 22 ■327 S3 8 4 ■328 S3 II II ■329 S3 14 17 -33° Si 18 o ■331 54 I 6 ■332 54 4 12 •333 54 7 19 ■334 54 II I •335 54 14 -8 '33(> 54 17 14 ■337 55 o 20 ■338 55 4 3 ■339 55 7 9 ■340 55 10 16 ■341 55 13 22 ■342 55 17 4 ASSAY OF GOLD OH SILVER. 245 If 200 Grains of One Ton of Ore Ore give of will yield of FINE METAL FINE METAL Gr. Oz. Dwts. Grs. ■343 56 on •344 56 3 17 ■345 56 7 o •346 56 10 6 ■347 56 ,13 12 •348 56 16 19 •349 57 o I •350 57 3 8 •351 57 6 14 ■352 57 9 20 •353 57 13 3 •354 57 16 9 •355 57 19 16 •356 58 2 22 •357 58 6 4 •358 58 9 " ■359 58 12 17 •360 58 16 o •361 58 19 6 •362 59 9 12 ■363 59 5 19 •364 59 9 I ■365 59 12 8 •366 59 15 14 •367 59 18 20 •368 60 2 3 •369 60 5 9 •370 60 8 16 •371 60 II 22 •372 60 IS 4 "373 60 18 II -374 61 I 17 •375 61 5 ° •>376 61 8 6 '377 ^'^ *'• ^* •378 61 14 19 If 200 Grains of One Ton of Ore Ore give of will yield of FINE METAL FINE METAL Gr. Oz. Dwts. Grs. •379 61 18 I •380 62 I 8 •381 62 4 14 •382 62 7 20 •383 62 II 3 •384 62 14 9 •385 62 17 16 •386 63 o 22 •387 63 4 4 •3-88 63 7 II •389 63 10 17 •390 63 14 o ■391 63 17 6 •39? 64 o 12 ■393 64 3 19 •394 64 7 I •395 64 10 8 ■396 64 13 14 •397 64 16 20 •398 65 o 3 ■399 65 3 9 •400 65 6 16 ■401 65 9 22 •402 65 13 4 •403 65 16 II •404 65 19 17 •405 66 3 o •406 66 6 6 ;4o7 66 9 12 '408 66 12 19 •409 66 16 1 •410 66 19 8 •411 67 2 14 •412 67 5 20 •413 67 9 3 •414 67 12 9 246 THE PRACTICAL ASS AVER. If 200 Grains of One Ton of Ore Ore give of will yield of FINE METAL FINE METAL Gr. Oz. Dwts Grs. ■415 67 IS 16 •416 67 18 22 ■417 68 2 4 ■418 68 s II •419 68 8 17 •420 68 12 •421 68 IS 6 •422 68 18 12 •423 69 I 19 •424 69 s I •42s 69 8 8 •426 69 11 14 ■427 69 14 20 •428 69 18 , 3 •429 70 I 9 •430 70 4 16 . •431 70 7 22 •432 70 II 4 •433 70 14 II •434 70 17 17 •435 71 I •436 71 4 6 ■437 71 7 12 •438 71 10 19 ■439 71 14 I •440 71 17 8 •441 72 14 •442 72 3 20 ■443 72 7 3 ■444 72 10 9 •445 72 13 16 •446 72 16 22 ■447 73 4 •448 73 3 II •449 73 6 17 ■45° 73 10 1 If 2CXJ Grains of One Ton of Ore Ore give of vpill yield of FINE METAL FINE METAL Gr. Oz. Dwts. Grs. •451 73 13 6 ■4S2 73 16 12 ■4S3 73 19 19 ■4S4 74 3 I ■4SS 74 6 8 ■4S6 74 9 14 ■4S7 74 12 20 ■4S8 74 16 3 ■4.S9 74 19 9 •460 75 2 16 ■461 75 5 22 ■462 75 9 4 ■463 75 12 II ■464 75 15 17 •465 7S 19 o ■466 76 2 6 •467 76 5 12 •468 76 8 19 ■469 76 12 I ■470 76 15 8 •471 76 18 14 •472 77 I 20 ■473 -77 5 3 •474 77 8 9 •47s 77 " 16 •476 77 14 .22 •477 77 r8 4 •478 78 I II ■479 78 4 17 •480 78, 8 o •481 78 II 6 •482 78 14 12 •483 78 17 19 •484 79 I I ■485 79 4 8 •486 79 7 14 ASSAY OF GOLD OR SILVER. 247 If 200 Grains of One Ton of Ore If 200 Grains of One Ton of Ore Ore give of will yield of Ore give of will yield of FINE METAL FINE METAL FINE METAL FINE METAL Gr. Oz. Dwts. &-S. Gr. Oz. Dwts. Grs. •487 79 10 20 •523 85 8 II ■488 79 14 3 , -524 85 II 17 •489 79 17 9 •525 85 15 •490 80 16 ■526 85 18 6 •491 80 3 22 •527 86 I 12 •492 80 7 4 ■528' 86 4 19 ■493 80 10 II •529 86 8 I •494 80 13 17 •53° 86 II 8 ■49 s 80 17 ■531 86 14 14 -496 81 o- 6 •532 86 17 20 •497 81 3 12 ■533 87 I 3 •498 81 6 19 •534 87 4 9 ■499 81 10 I •535 87 7 16 ■500 81 13 8 •536 87 10 22 ■501 81 16 14 •537 87 14 4 ■50Z 81 19 20 •538 87 17 II ■503 82 3 3 •539 88 17 ■S°4 82 6 9 •540 88 4 •s°s 82 9 16 •541 88 7 6 •506 82 12 22 •542 88 10 12 •507 82 16 4 •543 88 13 19 ■508 82 19 II •544 88 17 I 'S°9 83 2 17 •545 89 8 •510 83 6 •546 89 3 14 ■511 83 9 6 •547 89 6 20 -512 83 12 12 • 548 89 10 3 ■513 83 IS 19 •549 89 13 9 ■514 83 19 I •550 89 16 16 •515 84 2 8 •5SI 89 19 22 ■516 84 5 14 •552 90 3 4 ■517 84 8 20 •553 90* 6 II •518 84 12 3 •554 90 9 17 ■519 84 15 9 •555 90 13 •520 84 18 16 •556 90 16 6 •521 •522 85 I 22 •557 90 19 12 8S S 4 •558 91 2 19 248 THE PRACTICAL ASS AVER. If 200 Grains of One Ton of Ore Ore give of will yield of FINE METAL FINE METAL Gr-. Ot. Xhots. Grs, ■559 91 6 I ■560 91 9 8 •561 91 12 14 •562 91 15 20 •563 91 19 3 •564 92 2 9 ■565 92 S 16 •566 92 8 22 ■567 92 12 4 ■568 92 15 II •569 92 18 17 •570 93 2. o •571 93 S 6 ■572 93 8 12 ■573 . 93 " 19 ■574 93 IS I •575 93 I? 8 •576 94 I 14 ■577 94 4 20 •578 94 8 3 579 94 II 9 •580 94 14 16 •581 94 17 22 •582 95 I 4 ■583 95 4 II ■584 95 7 17 ' ■585 95 II o •586 95 14 6 •587 95 17 12 •588 96 o 19 ■589 -96 4 I ■590 96 7 8 ■591 96 10 14 •592 96 13 20 ■593 96 17 3 ■594 97 o 9 If 200 Grains of One Ton of Ore Ore give of will yield of FINE METAL FINE METAL Gr. Oz. Dwts. Grs. ■595 97 3 16 ■596 97 6 22 "597 97 10 4 ■598 97 13 II ■599 97 16 17 ■600 98 o o •601 98 3 6 •602 98 6 12 •603 98 9 19 •604 98 13 I ■605 98 16 8 ■606 98 19 14 ■607 99 2 20 ■608 99 6 3 •609 99 9 9 ■610 99 12 16 •611 99 15 22 ■612 99 19 4 ■613 100 2 II ■614 100 5 17 ■615 100 9 o ■616 100 12 6 ■617 100 15, 12 ■6i8 100 18 19 ■619 lOI 2 I ■620 loi s 8 •621 loi 8 14 ■622 lOI II 20 •623 loi IS 3 •624 lOI 18 9 •625 102 I 16 ■626 102 4 22 •627 102 8 4 ■628 102 II II ■629 102 14 17 ■630 102 18 o ASSAY OF GOLD OH SILVER. 249 If 200 Grains of One Ton of Ore Ore give of will yield of FINE METAL FJNE METAL Gr. Oz. JDwts. Grs. •631 103 I 6 •632 103 4 12 ■633 103 7 19 •634 103 n I •63s 103 14 8 •636 103 17 14 •637 104 o 20 •638 104 4 3 •639 104 7 9 •640 104 10 16 •641 104 13 22 •642 104 17 4 •643 105 on ■644 105 3 17 •645 105 7 o •646 105 10 6 •647 105 13 12 •648 105 16 19 •649 106 o I •650 106 3 8 •651 106 6 14 •652 106 9 20 •653 106 13 3 •654 106 16 9 •655 io6 19 16 •656 107 2 22 •657 107 6 4 •658 107 9 ii •659 107 12 17 •660 107 16 o ■661 107 19 6 ■662 108 2 12 ■663 108 5 19 •664 108 9 I •665 108 12 8 •666 108 IS 14 If 200 Grains of One Ton of Ore Ore give "of vfill yield of FINE METAL FINE METAL Gr. Oz. Dwts. Grs. ■667 108 18 20 •668 109 2 3 ■669 109 S 9 ■670 109 8 16 •671 109 ir 22 •672 109 15 4 •673 109 18 II •674 no i 17 •675 no s o ■676 no 8 6 ■677 no II 12 •678 no 14 19 •679 no 18 I •680 in I 8 •681 III 4 14 •682 III 7 20 •683 in n 3 •684 III 14 9 ■685 III 17 6 •686 112 o 22 687 .112 4 4 •688 112 7 II •689 112 10 17 •690 112 14 o •691 112 17 6 •692 113 o 12 •693 "3 3 19 •694 113 7 I ■69s 113 10 8 •696 113 13 14 •697 113 16 20 •698 114 o 3 •699 114 3 9 •700 114 6 16 •701 114 9 22 ■702 114 13 4 2 so THE PRACTICAL ASS AVER. If 200 Grains of One Ton of Ore Ore give of will yield of FINE METAL FINE METAL Gr. Oz. Dwts. Grs. ■703 114 16 12 ■704 114 19 17 ■70s "5 3 O ■706 115 6 6 •707 lis 9 12 •708 115 12 19 ■709 "5 16 I •710 115 19 8 ■711 116 2 14 •712 ii6 5 20 •713 116 9 3 ■714 116 12 9 •715 116 15 16 ■716 116 18 22 •717 117 2 4 ■718 117 5 11 •719 117 8 17 ■720 117 12 o •721 117 15 6 •722 117 18 12 •723 118 .1 19 •724 118 s I •725 118 8 8 •726 118 II 14 ■727 118 14 20 •728 118 18 3 •729 119 I 9 •730 119 4 16 •731 119 7 22 •732 119 II 4 ■733 119 14 II •734 119 17 17 "735 120 I o ■736 120 4 6 ■737 120 7 12 ■738 120 10 19 If 200 Grains of One Ton of Ore Ore give of will yield of FINE METAL FINE METAL Gr. Oz. Vwts. Grs. •739 120 14 I •740 120 17 2 ■741 121 o 14 ■742 121 3 20 ■743 121 7 3 •744 121 10 9 •745 121 13 6 ■746 121 16 22 •747 122 o 4 ■748 122 3 II ■749 122 6 17 ■750 122 10 o ■751 122 13 6 •752 122 16 12 753 122 19 19 754 123 3 I •755 123 6 8 •756 123 9 14 ■757 123 12 20 •758 123 16 3 "759 123 19 9 ■760 124 2 16 ■761 124 5 22 ■762 124 9 4 ■763 124 12 II ■764 124 15 17 •765 124 19 o ■766 125 2 6 ■767 125 5 12 •768 125 8 19 •769 125 12 I •770 125 IS 8 ■771 125 18 14 ■772 126 I 20 ■773 126 s 3 •774 126 8 9 ASSAY OF GOLD OR SILVER. 2SI If 200 Grains of One Ton of Ore Ore give of will yield of FINE METAL FINE METAL Gr. Oz. Dwts. Grs. 775 126 II 16 ■776 126 14 22 •777 126 18 ' 4 •778 127 I II ■779 127 4 17 •780 127 8 o •781 127 II 6 •782 127 14 12 ■783 127 17 19 •784 128 I I •78s 128 4 8 •786 128 7 14 •787 128 10 20 ■788 128 14* 3 •789 128 17 9 •790 129 o 16 •791 129 3 22 •792 129 7 4 •793 129 10 II •794 129 13 17 •79s 129 17 o ■796 130 o 6 ■797 130 3 12 ■798 130 6 19 •799 130 10 I •800 130 13 8 •801 130 16 14 •802 130 19 20 •803 131 3 3 ■804 131 6 9 •80s 131 9 16 •806 131 12 22 •807 131 16 4 ■808 131 19 II ■809 132 2 17 ■810 132 6 o If 200 Grains of One Ton of Ore Ore give of will yield of FINE METAL . FINE METAL Gr. On. Dwts. Grs. •811 132 9 6 ■812 132 12 12 •813 132 15 19 •814 132 19 I •815 133 2 8 •816 133 5 14 •817 133 8 20 ■818 133 12 3 ■819 133 15 9 '820 133 18 16 •821 134 I 22 ■822 134 5 4 •823 134 8 II •824 134 II 17 •825 134 IS o •826 134 18 6 ■827 13s I 12 •828 13s 4 19 •829, 13s 81 ■830 135 " 8 •831 13s 14 14 •832 13s 17 20 ■833 136 I 3 ■834 136 ■ 4 9 ■83s 136 7 16 •836 136 10 22 ■837 136 14 4 •838 136 17 II '839 137 o 17 •840 137 4 o •841 137 7 6 ■842 137 10 12 •843 137 13 19 •844 137 17 I ■84s 138 o 8 •846 138 3 14 252 THE PRACTICAL ASS AVER. If 200 Grains of One Ton of Ore Ore give of will yield of FINE METAL FINE METAL Gr. Oz. Dwts. Grs. •847 138 6 20 •848 138 10 3 •849 138 13 19 •850 138 16 16 •851 138 19 22 ■852 139 3 4 ■853 139 6 II ■854 139 9 17 ■855 139 13 o ■856 139 16 6 ■857 139 19 12 ■858 140 2 19 •859 140 6 I ■860 140 9 8 ■861 140 12 14 ■862 140 15 20 •863 140 19 3 ■864 141 2 9 •865 141 5 16 •866 141 8 22 ■867 141 12 4 •868 141 15 II •869 141 18 17 •870 142 2 o ■871 142 5 6 ■872 142 8 12 •873 142 II 19 •874 142 15 I •875 142 18 8 •876 143 I 14 ■877 143 4 20 •878 143 8 3 •879 143 " 9 •880 143 14 16 ■881 143 17 22 •882 144 I 4 I If 200 Grains of One Ton of Ore Ore give of will yield of FINE METAL FINE METAL Gr. Oz. Dwts. Grs. ■883 144 4 II •884 144 7 17 •885 144 I i O •886 144 14 6 •887 144 17 12 "888 145 o 19 •889 145 4 I •890 145 7 8 •891 145 10 14 ■892 145 13 20 ■893 145 17 3 ■894 i4(J o 9 •89s 146 3 16 •896 146 6 22. ■897 146 10 4 ■898 146 13 II ■899 146 16 17 ■900 147 o o •901 147 3 6 •902 147 6 12 '9°3 147 9 19 •904 147 13 I ■90s 147 16 8 •906 147 19 14 ■907 148 2 2 ■908 148 6 3 ■909 148 9 9 ■910 148 12 16 ■911 148 15 21 ■912 148 19 4 •913 149 2 II •914 149 5 17 •915 149 9 o ■916 149 12 6 ■917 149 15 12 ■918 149 18 19 ASSAY OF' GOLD OR SILVER. 2S3 If 2QO Grains of One Ton of Ore Ore give of will yield of FINE METAL FINK METAL Gr. Oz. JDwts. Grs. •919 150 2 I ■920 150 S 8 ■921 150 8 14 ■922 150 II 20 -923 150 IS 3 •924 150 18 9 •925 151 I 16 •926 151 4 22 •927 151 8 4 ■928 151 II ir •929 151 14 17 ■930 151 18 o •931 152 I 6 ■932 152 4 12 •933 152 7 19 ■934 152 ii I •93s 152 14 8 •936 152 17 14 •937 I S3 o 20 •938 153 4 3 •939 153 7 9 •940 153 10 16 ■941 153. 13 .22 -942 153 17 4 •943 154 o II "944 154 3 17 '945 154 7 o •946 154 10 6 ■947 154 13 " -948 154 16 19 •949 15s ° I •950 15s 3 ^ '951 15s ° 14 •952 155 9 20 ■953 155 13 3 •954 155 16 9 If 200 Grains of One Ton of Ore Ore give of will yield of FINE METAL FINE METAL Gr. Oz. jDwts, Grs. •955' 155 19 16 •956 156 2 22 ■957 156 6 4 •958 156 9 II •959 156 12 17 •960 156 16 o •961 156 19 6 ■962 157 2 12 •963 157 5 19 •964 157 9 I •965 157 12 8 •966 157 15 14 ■967 157 18 20 •968 158 2 3 •969 158 s 9 •970 158 8 16 ■971 158 II 22 •972 158 15 4 •973 158 18 II ■974 159 I 17 ■975 159 5 o •976 159 8 6 ■977 159 " 12 •978 159 14 19 ■979 159 18 .1 ■980 160 I 8 •981 160 4 14 •982 160 7 20 '983 160 10 3 •984 160 14 9 •985 160 17 6 1986 161 o 22 •987 161 4 4 •988 161 7 II •989 161 10, 17 •990 161 14 o 254 THE PRACTICAL ASS AVER. If 200 Grains of One Ton of Ore If 200 Grains of One Ton of Ore Ore give of will yield of Ore give of will yield of FINE METAL FINE METAL FINE METAL FINE METAL Gr. 0«. Dwts. C»-j. Gr. Oz. Dwts. Crs. ■991 161 17' 6 28 4573 6 16 •992 162 12 29 4736 13 8 •993 162 3 19 30 4900 •994 162 7 I 31 5063 6 16 ■99s 162 10 8 32 5226 13 8 •996 162 13 14 Z2, 539° ■997 162 16 20 34 5553 6 16 •998 163 3 35 5716 13 8 •999 163 3 9 36 5880 I gram 163 6 16 37 6043 6 16 2 326 13 8 38 6206 13 8 3 490 39 6370 4 653 . 6 16 40 6533 6 16 5 816 13 8 41 6696 13 8 6 980 42 6860 7 "43 6 16 . 43 7023 6 16 8 1306 13 8 44 7186 13 8 9 1470 45 7350 10 1633 6 16 46 7513 6 16 II 1796 13 8 47 7676 13 8 12 i960 48 7840 13 2123 6 16 49 8003 6 16 14 2286 13 8 50 8166 13 8 IS 2450 51 8330 16 2613 6 16 52 8493 6 16 17 2776 13 8 53 8656 13 8 18 2940 54 8820 19 3103 6 16 55 8983 6 16 20 3266 13 8 56 9146 13 8 21 3430 57 9310 22 3593 6 16 58 9473 6 16 23 3756 13 8 59 9636 13 8 24 3920 60 9800 25 4083 6 16 61 9963 6 16 26 4246 13 8 .62 10126 13 8 27 4410 63 10290 ASSAV OF GOLD OR SILVER. 2SS If 200 Grains of One Ton of Ore Ore give of will yield of FINE METAL FINK METAL Gr. Oz. Dwts. Grs. . 64 10453 6 16 65 10616 13 8 66 10780 o o 67 10943 6 16 68 11106 13 8 69 11270 o o 70 11433 6 16 71 11596 13 8 72 11760 o o 73 11923 6 16 74 12086 13 8 75 . 12250 o o 76 12413 6 16 77 12576 13 8 78 12740 o o 79 12903 6 16 80 13066 13 8 81 13230 o o 82 13393 6 16 83 13556 13 8 84 13720 o o 8s 13883 6 16 86 14046 13 8 87 14210 o o 88 14373 6 16 89 14536 13 8 90 14700 o o 91 14863 6 16 92 15026 13 8 93 15190 o o 94 I53S3 6 16 95 15516 13 8 96' 15680 o o 97 15843 6 16 98 16006 13 8 99 16170 o o If 200 Grains of One Ton of Ore Ore give of will yield of FINE METAL FINE METAL Gr. Oz. Dwts. Grs. 100 16333 6 16 101 16496 13 8 102 16660 o o 103 16823 6 16 104 16986 13 8 105 17150 o o 106 17313 6 16 107 17476 13 8 108 17640 o o 109 17803 6 16 no 17966 13 8 111 18130 o o 112 18293 6 16 113 18456 13 8 114 18620 o o 115 18783 6 ' 16 116 18946 13 8 117 19110 o o 118 19273 6 16 119 19436 13 8 120 19600 o o 121 19763 6 16 122 19926 13 8 123 20090 o o 124 20253 6 16 125 20416 13 8 126 20580 o o 127 20743 6 16 128 20906 13 8 129 21070 o o 130 21233 6 16 131 21396 13 8 132 21560 o o 133 21723 6 16 134 21886 13- 8 135 22050 o o 256 THE PRACTICAL ASS AVER. If 200 Grains of One Ton of Ore Ore give of will yield of FINE METAL FINE METAL Gr. Oz. Dwts. Grs. 136 22213 6 16 137 22376 13 8 138 22540 ■ o o ' 139 22703 6 16 140 22866 13 8 141 23030 o o 142 23193 6 16 143 23356 13 8 144 23520 o o 14s 23683 6 16 146 23846. 13 8 147 24010 o o 148 24173 6 16 149 24336 13 8 150 24500 o o X51 24663 6 16 152 24825 13 8 153 24990 o o 154' 25153 6 16 155 25316 13 8 156 25480 o o 157 25643 6 16 158 25806 13 8 159 25970 o o 160 26133 6 16 r6i 26296 13 8 162 26460 o o 163 26623 6 16 164 26786 13 8 165 26950 o o 166 27113 6 16 167 27276 13 8 168 27440 o o If 200 Grains of One Top of Ore Ore give of will yield of ■PINE METAL FINE METAL Gr. Oz. Dwts. Grs. 169 27603 6 16 170 27766 13 8 171 27930 o o 172 28093 ■ 6 16 173 28256 13 8 174 ' 28420 o o 17s 28583 6 16 176 28746 13 8 177 28910 o o 178 29073 6 16 179 29236 13 8 180 29400 o o 181 29563 6 16 182 29726 13 8 183 29890 o o 184 30053 6 16 185 30216 13 8 186 30380 o o 187 30543 6 16 188 30706 13 8 189 30870 o o 190 31033 6 16 191 31196 13 8 192 31360 o o 193 31523 6 16 194 31686 13 8 ■ 195 31850 o o 196 32013 6 16 197 32176 13 8 198 32340 o o ^99 32503 6 . 16 . 200 32666 13 8 Printed by J. Ogdkn and Co., 172, St John Street, E.C. at Piccadilly drctis.^ [Aprti, 1874.] A LIST OF BOOKS PUBLISHED BY CHATTO & WiNDUS, ^^&'^l, Piccadilly, London, w. THE FAMOUS PEASER PORTRAITS. MACLISE'S Gallery of Illustrious Literary Characters. With Notes by the late WILLIAM MAGINN, LL.D. Edited, with copious Notes, by. William Bates, B.A., Professor of Classics in Queen's College, Birmingham. The volume contains the whole 83 Splendid and most Characteristic Portraits, now first issued in a complete form. In demy 410, over 400 pages, cloth gilt and gilt edges, 31J. dd. " Most interesting.*^ — Saturday Review, " Not p'ossible to imagine a more elegant addition to a diawing-room table."— /"««. " One of the most Interesting volumesof this year's literature." — Times. "Deserves a place on every drawing-room table, and may not unfitly be removed from the drawing-room to the library. ' — Spectator. 74 <&> 7S, PICCADILLY, LONDON, W. 2 BOOKS PUBLISHED BY CHATTO &= WINDUS. NEW FINE-ART GIFT-BOOK. THE NATIONAL GALLERY. A Selection from its Pictures, by Claude,- Rembrandt, Cuyp, Sir David Wilkie, , Correggio, Gainsborough, Canaletti, VandVck, Paul Veronese, Caracci, Rubens, N. and G. PoussiN, and other great Masters. Engraved by George Doo, John Burnet, William Finden, John and Henry Le Keux, John Pye, Walter Bromley, and others. With descriptive Text. A New Edition, from the original Plates, in Columbier 4to, cloth extra, gilt and gilt edges, 3IJ. ()d. [Nearly ready. WORKS OF JAMES GILLRAY, CARICATURIST. With the Story of his Life and Times, and full and Anecdotal De- scriptioiis of his Engravings. Edited by Thos. Wright, Esq., M.'A., F.S.A. ',• Illustrated vfith 83 full-page Plates, and very numerous Wood Engravings. Demy 4to, 600 pages, cloth extra, 3IJ. 6d. "The work is well done. A handsome y olume, produced regardless of expense.*' ~Staftdard. " The publishers have done good service in bringing so much thatis full of humour and of historical interest withm the reach of a Iarga.c]siss."—Saiuniay Review. "One of the most amusing .and valuable illustrations of the social and polished life of that generation which it is possible to conceive." — Spectator. BEAUTIFUL PICTURES BY BRITISH ARTISTS. A Gathering of Favourites from our Picture Galleries, 1800 — 1870. By Wilkie, Constable, J. M. W. Turner, ATulreadt, Sir Edwin Landseer, Maclise, Leslie, E. M.Ward, Frith, Sir John Gilbert, Ansdell, Marcus Stone, Sir Noel Paton, Eyre Crowe, Faed, Madox Brown. All Engraved in the highest style of Art. With Notices of the Artists by Sydney Armytage, M. A. A New Edition. Imperial 4to, cloth gilt and gilt edges, 21 j. COURT BEAUTIES OF THE REIGN OF CHARLES II. From the Originals in the Royal. Gallery at Windsor, by Sir Peter Lely. Engraved in the highest style of art by Thoiison, Wright, Scriven, B. Holl, Wagstaff, and T. A. Deane. With Memoirs by Mrs. Jameson, Author of "Legends of the Madonna." New and sumptuous "Presentation Edition." Imp. 4to, cloth gilt and gilt edges, 2lx. "This truljr beautiful and splendid production is equally a gem among thfc Fine Arts and in Literature." — Quarterly Review, 74 &• 7S, PICCADILLY, LONDON, W. BOOKS PUBLISHED BY CHATTO 6» WINDUS. MATT MORGAN'S DESIGNS. THE AMERICAN WAR: Cartoons by Matt Morgan and ofter Artists, illustrative of the late Great Civil War in America. Now first collected, with Explana- tory Text. Demy 4to, illustrated boards, Is. td. Companion to the " History of Signboards." Advertising, A History of, from the Earliest Times. Illustrated by Anecdotes, Curious Specimens, Biographical Notes, and Examples of Successful Advertisers. By Henry Sampson. Crown 8vo, with Frontispiece and numerous Illustrations, coloured and plain, cloth extra, ^s. (yd. [In p-eparaiiott. Anacreon. Illustrated by the Exquisite Designs of Girodet. Trans- lated by Thomas Moore. Bound in E_truscan gold and blue, 12s. 6d. *,• A leauti/ul and captivating volume. The well-kfunvn Paris houses Firmin Didoi^ a/ew years since produced a miniature edition of these exquisite designs by photography^ and sold a large number at £!i per copy. The Designs have been universally admired by both artists and poets. The Art of Amusing. A Collection of Graceful Arts, Games, Tricks, Puzzles, and Charades, intended to amuse everybody, and enable all to amuse everybody else. By Frank Bellew. With nearly 300 Illustrations. Crown 8vo, 4J. &/. •^* One of the most entertaining hand- books ^amusements ever published, A>A/f u I C ram m e rs. A New American Joke Book. Edited by Titus A. Brick, Author d. *»* TMs work gives practical methods/or testing the quaUty of gold and silver. It was coTHpiledby the author for his own use, and as a Supplement to "Chajirs." 74 &> 75, PICCADILLY, LONDON, W. BOOKS PUBLISHED BY CHATTO &• WIITDUS. BRET HARTE'S WORKS. Widely knomnfor their Exquisite Pathos and DdigtUful Humour. Bret Harte'sOom- plete Works, in Prose and Poetry. Now First Collected. With Introductory Essay by J., M. BelleWi Portrait of the Author, and 50 Illustrations. Crown 8vo, 650 pages, cloth extra. Is. M. Bret Harte's Luck of Roaring Camp, and other Stories. Fcap. 8vo, illustrated cover, IS, Bret Harte's That Heathen Chinee, and other Humorous Poems. Fcap. 8vo, illustrated cover, l^. dd. Bret Harte's Sensation Novels Con- densed. Fcap. 8vo, illustrated cover, is. 6d. *,fA trust enjoyable took, only surpassed, in its special class, iy Thackeray's Burlesque Novels. Bret Harte's Lothaw ; or, The Adventures of a Young Gentleman in Search of a Religion. By Mr. Ben- lAMiNS (Bret Harte). Price 613^, Curiously Illustrated. Bret Harte's East and West. Fcap. 8vo, illustrated cover, i^. Bret Harte's Stories of the Sierras, and other Sketches. With a WQd Story of Western Life by Joaquin MlLtER, Author of " Songs of the Sierras." Illustrated cover, \s. Booth.'s Epigrams : Andent and Modqrn, Humorous, Witty, Satirical, Moral, and PanegyrjcaL Edited by the Rev. John BooxHj B. A. A New Edition. Pott8vo, cloth gilt,6j. 74 &> 7S, PICCADILLY, LONDON, JK BOOKS PUBLISHED B\ CHATTO &> WJNDUS. Brewster's (Sir David) More Worlds than One, the Creed of the Philosopher and the Hope of the-Christian. A New Edition, in small crown 8vo, cloth, extra gilt, with full-page Astronomical Plates, uniform with Faraday's " Chemical History of a Candle." 4J. dd. [Nearly ready. Brewster's (Sir David) Martyrs of Science. A New Edition, in small crown 8vo, cloth, extra gilt, with fuU-page Portraits, uniform with Faraday's "Various Forces of Nature;" 4J. dd. ' ; [Nearly ready . NEW BODE FOB BOTS. The Conquest of the Sea: A History of Divers and Diving, from the Earliest Times to the Present Day. By Henry Siebe. Profusely Illustrated with.fine Wood Engravings. Small crown 8vo, cloth extra, 4^. (>d. "We have perused this volume, full of quaint informalion, with delight. Mr. Siehe has bestowed much pains on his work ; he writes with enthusiasm and fulness of knowledge." — Echo. " Really mterestin^ Alike to youths and to grown-up ^o^\e." -^Scotsman, "Equally interestmg, to the general and to the scientific reader. "-'JI/iTrffMtf Advertiser. ' ■ 74 &' 75. PICCADILLY, LON DON, W. BOOKS PUBLISHED BY CHATTO &» WINDUS. Bright's (Rt. Hon. J., M.P.) Speeches on Public Affairs of the last Twenty Years. Collated with the best Public Reports. Royal l6mo, 370 pages, cloth extra, \s. *•* A book of special interest at the present time, and wonderfully cheap. COLMAN'S HUMOROUS WORKS. Broad Grins. My Nightgown and Slippers, and other Humorous Works, Prose and Poetical, of George Col- man the Younger. Now first collected, with Life and Anecdotes of the Author, by George B. Buckstone. Crown 8vo, 500 pp.,7J. (id. ^^ Admirers of -genuine English wit and humour will he delighted with this edition 0/ George Caiman's humorous works. As a wit, he has had no equal in our time ; and. a man with a tithe of his ability could, at the present day, make the fortune of any of our comic journals. Carlyle (T.) on the Choice of Books. Witji New Life and Anecdotes. Brown cloth, uniform with the 2^. Edition of his Works, is. 6d, ; paper cover, is. Celebrated Claim- ants, Ancient and Modem. Being the Histories of all the most cele- brated Pretenders and Claimants 600 years. , Fcap. , illustrated boards, *** This book is presented to ike pub' lie ai a time ivhen popular attention, is attracted to the sub- ject of which it treats ; but it is in- tended Tnuch less, to gratify a temporary curiosity than to fill an empty Page in our literature. - In our own and in other countries Claimants have been by no means rare, and the tuthor has spared no research to render his work as perfect as possible^ and to supply a reliable history of those cases which are e7ititled to rank as causes calibres. The book is ^i forward in the hope that, while it may serve to amuse the hasty reader in a leisure hour, it may also be deemed worthy of a modest resting-place in the libraries of those who like to watch the march of events, and who have theprmUnt ' hmdit, when information is founds of preserving a note of it. 74 ^ *il, PICCADILLY, LONDON^ W, lo BOOKS PUBLISHED BY CffATTO &^ WINDUS, NEW AND IMPORTANT WORK. The Cyclopaedia of Costume; or, A Dictionary of Dress, Regal, Ecclesiastical, Civil, and Military, from the Earliest Period in England to the reign of George the Third. Including Notices of Contemporaneous Fashions on the Continent, and preceded by a General History of the Costume of the Principal Countries of Europe, By J. R. Planch£, F.S.A., Somerset Herald, ^Tkis work will he published in Twenty-four Monthly Parts, quarto, at Five ShilliTigSt profusely illustrated by Plates and Wood Engravings ,* wiM each Part will also be issued a splendid Coloured Plate^from an original Painting or Iliu- vnination^ of Royal and Noble Personages ^ and National Costume, botk foreign and domestic. The First Part is just ready. IN collecting materials for a History of Costume of more importance than the little handbook which has met with so much favour as an elementary work, I was not only made aware of my own deficiencies, llut sur- prised ta find how much more vague are the explana- tions, and contradictory the statements, of o.ur best authorities, than they appeared to me, when, in the . plenitude of my4gnorance, I rushed upon almost un- ' trodden ground, and felt bewildered b>r the mass of unsifted evidence and unhesitating assertion which met ray eyes at every turn. 1 During the forty years which have elapsed since the I publication of the first edition of my ' ' History of British Costume" in the "Librarjr of Entertaining Know- ledge," archeeological investigaUon has received such an impetus by the establishment 'of metropolitan and provincial peripatetic antiquarian societies, that a flood of light has been poured upon us, by which we are enabled to re-examine our opinions and discover reasons to doubt, if we cannot find facts to authenticate. ^ That the former greatly preponderate is a grievous acknowledgment to make after assiduously devoting the leisure of half- my life to the pursuit of information on this, to me, most fascinating, subject. It is some consolation, however, to feel that^'I^nere I cannot in- struct, I shall certainly not mislead, and that the reader will find, under each head, all that is known to, or suggested by, the inost compeHnt writers I am ac- quainted withj. either here or on the Continent. That this work appears in a glossanal form arises from the desire of many artists, who have expressed to me the difficulty they constantly meet with in their en- deavours to ascertain the complete form of a garment, or the exact mode of fastening a piece of armour, or buckling of a belt, from their study of a sepulchral effigy or a figure in an illumination, the attitude of the personages represented, or the dispo- sition of other portions of their attire, effectually preventing the requisite examination. (The books supplying any such information are very few, and the best confined to armour or ecclesiastical costume. The only English publication of the kind' required, that I am aware of, is the late Mr. FaiirtaSlt's ''Costume in England " (8vo, London, 2846), the last two hundred pages of which contain a glossary, the most valuable portion whereof are the quotations from old plays, mediaeval romances, and satirical ballads, containing allusions to various articles of attire in fashion at the time of their composition. Twenty-eight years have expired since that book appeared, and k has been thought that a more comprehensive work on the subject than has yet issued from the English press, combining the pith of the information of many costly foreign publications, and, in its illustrations, keeping in view the special require- ment of the artist, .to which I have alluded, would_ be, in these^ days of educational progress and critical inquiry, a welcome addition to the library of an English gentleman. J. R. PLANCHE, 74 6-75, PICCADILLY, LONDON, W. BOOKS PUBLISHED BYCHATTO.&' WINDUS. l\ Christmas Carols and Ballads. Selected and Edited by Joshua Sylvester. A New Edition, beautifully printed and bo und in cloth, extra gilt, gilt edges, y. 6d. Cierical Anecdotes and Pulpit Eccen- tricities. Square r6mo, illustrated wrapper, is. ^.i cloth neat, I J. lod. The Country of the Dwarfs. By Paul DU ChaiIjLU. Fcap. 8vo, full-page Engravings, fancy wrapper, is. Cruikshank's Comic Almanack. Complete in Two Series : the First from 1835 to 1843 ; the Second from 1844 to 1853. A Gathering of the Best Humour of Thackeray, Hood, Mayhew, Albert Smith, A'Beckett, Robert Brougk, &c. With 2,000 Woodcuts and Steel Engravings by Cruikshank, Hine, Landells, &c. Crown 8vo, cloth gilt, two very thick volumes, l^s.; or, separately, 7j. 6ii. per volume. I. APPROACH OF BLUCHBR: INTREPID ADVANCE OP THE FIRST FOOT. •«• The'* Comic Almanacks " of George C'ruikshanJe have long been regarded By etdmifers of this inimitable artist as among his Jines't, most characteristic pro' duetiotts.. Extending over a perwd of nineteen ysars^Jrom 1835 to 1853, inclusive^ they embrace the best period of his artistic career^ and show the varied excellences of his tnantellous power. The late Mr. TUty 0/ Fleet Street^ first conceived the idea of the " Cotatc Almanack*' and at various times there were engaged upon it such writers as Thackeray, Albert Smith, the Brothers Mayhew, 'the late Robert Brougk, Gilbert A'Beckett, and, it has been asserted^ Tom Hood the elder. Thackeray's stories of " Stubbs' Calendar; or, The Fatal Boots," which subsequently appeared as ** Stubbs' Diary; " and "Barber Cox; or. The Cutting of His'J^ombj formed ike leading attractions in the numbers for 1839 and 1840. 74 (5- 75, PICCADILLY, LONDON, VT, 12 BOOKS PUBLISHED BY CHATTO or- WINDUS. THE BEST GUIDE TO HERALDRY. Cussans' Handbook of Heraldry; with Instructions for Tracing Pedigrees and Deciphering Ancient MSS.; also, Rules for the Appointment of Liveries, &c., &c. By John E. Cussans. Illus- trated with 360 Plates and Woodcuts. Crown 8vo, cloth extra, gilband emblazoned, is. td. *«* This volum^f heautifuUy printed on iottedpa^eTt contains not only the ordinary matter to he found in the best books on the science of Armory ^ but seve^ 1 al other subjects hitherto ■ unnoticed. Amongst these may be mentioned: — i. Bikections for Tracing Pedigrees. 2. Deciphering Ancient mss., illustrated by alphabets and f'ac- siMiLES. 3. The Appointment 'of Liveries. 4. Continental and American Heraldry, &c. VERT IMPORTANT COUNTY HISTORY. Cussans' History of Hertfordshire. A County History, got up in a very superior manner, and ranging with the finest works of its class. By John E. Cussans. Illus- trated with full-page Plates on Copper and Stone, and a profusion of small Woodcuts. Parts I. to VI. are now ready, price 21s. each. *,* An entirely new History of this important County, great attention being given to all matters pertaining to the Family History of the locality. 74 &' 7S, PICCADILLY, LONDON, W. BOOKS PUBLISHED BY CHATTO &>' WINDVS. .13 The Dan bury Newsman. A Brief but _ , Ponjprehensive Record of the Doings of a Remarkable People, under more Remarkable Circumstances, and Chronicled in a most Re- markable Manner. By James M. Bailey. Uniform with Twain's " Screamers." Tcap. 8vo, illustrated cover, \s. " A real American humourist." — Figaro. Uniform with the "Charles Dickens Edition." Dickens : The Story of his Life. By Theodore TaV- LOR, Author of the "Life of Thackeray." Uniform with the " Charles Dickens Edition " of his Works, and forming a Supple- mentary Volume to that Issue. Crown- 8vo, crimson cloth, 3j. (td. "Anecdotes seem to have poured in upon the author from all quarters. . . Turn where we will through these 370 pleasant pages, something worth reading is sure to meet the eye."— yAe Standard. A.1SO Published : The "Best Edition" of the above Work, illustrated by Photo- graphic Frontispiece of " Dickens as Captain Bobadil," Portraits, Facsimiles, &c. Crown 8v», cloth extra, 7^. (>d. The " Cheap Edition," in i6mo, paper wrapper, with Frontispiece and Vignette, 2s. Uniform with the " Charles Dickens Edition." Dickens' Speeches, Social and Literary, now first collected. Uniform with, and forming a Supplemen- tary Volume to, the " Charles Dickens Edition." Crown 8vo, crimson cloth, 3^. ^d. "• " His speeches are as good as any of his printed writings."—?'^ Times. Also Published: The " Best Edition," in crojvn 8vo, witi fine Portrait by Count D'Orsay, cloth extra. Is. 6d. • The "Cheap Edition," in i6mo, paper wrapper, zs. Dickens'.jLife and Speeches, One Volume, .i6mo, cloth, 2s. 6d. il'i^ &' 11,' PICCADILLY, LONDOM, W. 14 BOOKS PUBLISHED BY CHAT70 &' WINDUS. BALZAC'S CONTES DEOLATIQTJES. Droll Sto- ries, colFected from the Ab- beys of Tou- raine. Now FIRST TRANS- lated into English, Complete and Unabridged. With the whole 425 Marvellous, Ex- travagant, and Fantastic Illus- trations by Gus- ' TAVE DoRfi. Beautifully print- ed, in 8vo, cloth extra, gilt, gilt top, I2J. dd. A few copies of the French Origi* NAL are still on sale, bound half- Roxburghe, gilt top— a very hand- some book — price . \2s. bd. The Derby Day. A Sporting Novel of intense interest Fcap. 8vo, illustrated cover, \s. Disraeli's (Rt. Hon. B.) Speeches on the Conservative Policy of the last Thirty Years, including the Speech at the Literary Fund Dinner, specklly revised by the Authbc Royal i6mo, paper cover, with Portrait, \s. \i. ; in cloth, \s. lorf. 74 <&» 7S, PICCADILLY^ LONDON, H\ BOOKS PUBLISH ED BY CHATTO 6^ WINDUS. 15 D'Urfey's ("Tom") Wit and Mirth: or, Pills to Purge Melancholy : Being a Collection of the best Merry Ballads and Songs, Old an^ New. Fitted to all Hu- mours, having each their proper Tune for either Voice or Instrument : most of the Songs being new set. London: Printed by W. Pearson, for J. Tonson, at Shakespeare's Head, over-against Cathe- rine Street in the Strand, 1719. An exact and beautiful reprint of this much-prized work, with the Music to the Songs, just as in the rare original. In 6 vols., large fcap. 8vo, antique boards, edges uncut, beautifully printed on laid paper, made expressly for the work, price ;^3 3^. *** The Pills to Purge Melancholy have now retained their celebrity for a century and a half. The difficulty of obtaining a copy has of late years raised sets to a fabulous firice, and has made even odd volumes costly. > Considering^ the clas" si£al reputation which tlte book has thus obtained^ and its very high interest as tllustrative of the manners^ customs^ and amusetnenis of English life during the half-century following the Restoration, no apology is needed for placing such a work ntore within the reach of general readers and students 'by re-issuing ttfor the_first time siftce its original appearance^ and at about a tithe of the Price for which the old edition could now be obtained^ ^or drinking-songs and love-songs^ sprightly ballads, merry stories^ and Political sguibSf there^ are none to surpass these in ike language. In ivtprovistng iuch pieces^ and in singing them, D'Urfey was Perhaps nez'er egualled, except in our own century by Theodore Hook. The sallies of kis wit amused ami deUghted three successive English sovereigns ; and white his plays are forgotten., his songs and ballads still retain the light abandon and joyous ^eshness that recotHmended thetn to the wits and beaux of Queen Anne's days. Nor can the warpt and affec- tionate eulogy of Steele and Addison he forgotten, and Ti'V^VKV may now takekis place on the bookshelves of the curimts, side by side with the other worthies of his age. The Earthward Pilgrimage, from the Next World to that which now is. By Moncure D. Conway. Crown 8vo, beautifully printed and bound, Is. dd. Mrs. Ellis's Mothers of Great Men. A New Edition of this well-known Work, with Illustrations by Valentine W. Bromley and others. Crown 8vo, doth ^t, over 500 pages, 6j. Emanuel on Diamonds and Precious Stones ; Their History, Value, and Properties ; with Simple Tests for ascertaining their Reality. By Harry Emanuel, F.R.G.S. With numerous Illustrations, Tinted and Plain. A New Edition, Crown 8vo, cloth extra, gilt, 6r. ■ 74 iSf 75, PICCADILLY, LONDON, W. i6 BOOJCS PUBLISHED BK CHATTO ^ WINDUS, Edgar Allan Poe's Prose and Poetical Works ; including Addifional Tales and the fine Essays by this VOii S COTTAGE AT FORDHAM. great Genius, now First Published in this Country. With a Translation of Charles Baudelaire's "Essay on Poe." 750 pages, crown 8vo, fine Portrait and Illustrations, cloth extra, ^s.^d. The ^English Rogue, described in the Life of Meriton Latroon, and other Extravagants, comprehending , the most Eminent Cheats of both Sexes. By Richard Head and Francis Kirkman. A facsimile reprint of the rare Original Edition (1665-1672), with a Frontispiece and Portraits of. the Authors. In 4 Volumes, . large foolscap 8vo, beautifully printed on antique laid paper, : made expressly, and bound in antique boards, 32^.; or Large-paper Copies, 52J, {Nearly ready. *#* This singularly entertaining, work may be described as tJte first English novel, properly so called. The same air of reality pervades it as that which gives such a chartn to the stories written by Defoe' ha^ a century later. The interest never fiags for a moment, front the first chapter to the last. As a picture of the manners of ike Period, two hundred years ago, in England, atnong the various grades of society through, which the hero Passes in the course of his extraordinary' adventures, and among gipsies, beggars; thieves, io'c., the book is invaluable to students. The earlier portion of the hook was considerably altered in later editions by Francis Kirkmatt. While preserving all the additions made by that writer, most of the omitted passages (sometimes among the most characteristic iH the book) have b^en restoredfrom the earliest' edition, which is of the very greatest rarity, most of the copies having been destroyed, the year after its publication, in the Great Fire of London. The later edition and the Second Part are of almost equal rarity. Owing to its wondetful run of popularity, the book^has been so well read and well thumbed, that perfect copies are very seldom to be met ivith, and are then only to be obtained at an extravagantly high price. The present reprint m.ay therefore be useful and accept- able to students ^ Early English Literature. 74 ^ 75, PICCADILLY, LONDON^ W, BOOKS PUBLISHED BY CHATTO &= WIND US. 17 Our English Surnames: Their Sources and Significations. By Charles Wareing Bardsley, M.A. Crown 8vOi about 600 pages, clotk extra, gj. •«• A compute wori; cmtaining very much that is not to he found in Mr. Lower's weU-kniniun vglvme. ^ The chapters are drraneed under the following heads: — i. Baptismal OR Personal Names; .2.. Local SujiNAMKS,; 3. Official Surnames ; 4. Occupatjve Surnames; 5. Sobriquet SuRNAMfcs, or Nicknames. EARLY NEWS SHEET. The Russian invasion of Poland in 1563. (Memoiabilisetperindestupenda.de criideli Moscovitarum Expeditibne Narratio, e Gennanico.in Latinuiii conversa. ) An exact facsimile of a contemporai^ account in Latin, published at Douay, together with an Introduction and Historical- Notes aiid a full Trans- lation. Only 100 copies printed.- Large fcap. 8v6, an exact fac- simile on antique. ■pkt)er, hardly distinguishable from the original, half-Roxburghe, price ^s. td. ■ The Englishman's House, from a Cot- tage to a Mansion. A Practical Guide to Members of Building Societies, and all interested in Selecting or Building a House. By C.J. Richardson, Architect, Author of " Old English Mansions," &c. Second Edition, Corrected and Enlarged, with nearly 600 Illustrations. Crown 8vo, 550 pajjes, cloth, 7j. 6d. The Fiend's Delight: A "Cold Collation" of Atrocities. By DoD Grile. ■ New Edition, in illusfcrated wrapper, fcap. 8vo, \s, . ' ' ... "A specimen of 'American Humour' as unlike that of all other American humourists, as the play of young human Merry-Andrews is vinlike that; of .^ young and energetic demon whose'horns are well budded. "^^—iyifzi* Var^ Nation. The Finish to Life in and out of London ; or. The Final Adventures of Tom, Jerry, and Logic. By Pierce Egan. Royal 8vo, cloth extra, with Spirited Coloured Illustrations by CruikshanK, Zls. Fun for the Million : A. Gathering of Choice Wit and Humour, Good Things, and Sublime Non- sense, by Dickens, Jer. ROLD, Sam Suck, Chas. H. Ross, Hood, Theo- dore Hook, MarkTwain, Brough, Colman, Titus A. Brick, and a Host of other Humourists. With Pictures by Matt Mor- gan, Gilbert, Nast, Thompson, Cruik.shank, Jun., Brunton, &c. In fcap.. 4to, profusely illus- trated, with picture wrap- per, IS. r . t i ■ 74 &= 75, PICCADILLY, LONDON, W. BOOKS PUBLISHED BY CHATTO. &=, WINDUS. 19 Walk up 1 Walk up ! and see the Fools' Paradise ; with the Many Wonder- ful Adventures there, as seen in the strange, surprising PEEP-SHOW OF PROFESSOR WOLLEY COBBLE, Raree Showman these Five-and-Twenty Years. Crown 4to, with nearly 200 immensely funny Pictures, all beautifully coloured, bound in extra cloth gilt, price Is. 6d. -THE professor's LEETLE MUSIC LESSON, A Second Series is now Ready, called FurtherAdventures in Fools' Paradise, with the Many Wonderful Doings, as seen in the PEEP-SHOW OF PROFESSOR WOLLEY COBBLE. Crown 4to, with the Pictures beautifully Coloured, uniform with the First Series, in extra cloth gilt, price is. 6d. THE OLD SHBKAREY. The Forest and the Field : Life and Adventure in Wild Africa. By the i Old Shekarry. ' With Eight Illustrations. Crown 8vo, cloth extra, gilt, 6^. •*• The Author has ' endeavoured to record his impressions of some of the grandest scenery in the world, as^ well as of_ the dreary swamps tf the^ Eastern coast of Equatorial Africa. It is a book of intense interest^ especially for hoys. Wrinkles ; or, Hints to Sportsmen and Travellers upon Dress, Equipment, Armament, and Camp Life. By the Old Shekarry.- A New Edition, with Illustrations. Small Crown 8vo, cloth extra, gilt, (>f. 74 <&* 75. PICCADILLY, LONDON^ W. 20 BOOKS PUBLISHED BY CHATTO &» WiNDUS. The Genial Showman ; or, Show Life in the New World. Adventures with Artemus Ward, and the Story of his Life. By E. P. Kingston. Third Edition. Crown 8vo, Illus- trated by Brunton, cloth extra, "js. (>d. RTJSKIN AND CRUIKSHANE. German Popular Stones. Collected by the Brothers Grimm, and Translated by Edgar Taylor. Edited by John Ruskin. With 22 Illustrations after the inimitable designs of George Cruikshank. Both Series complete. Square, crown 8vo, 6.f. (>d. ; gUt leaves, ys. 6ti. •*• These are the designs which My. Ruskin haspraised so highly, placing them 'ar above all Cruikshank^ s other works 0/ a similar character. Gesta Romanorum ; or, Entertaining Stories, invented by the Monks as a Fireside Recreation, and com- monly applied in their Discourses from the Pulpit. A New Edition, , with Introduction by Thomas Wright, Esq., M.A., F.S.A. Two vols, large fcap. 8vo, printed on fine ribbed paper, i8j. Gladstone's (Rt. Hon. W. E.) Speeches on Great Questions of the Day during the last Thirty Years. Col- lated with the best public reports. Royal i6mo, paper cover, \s. 41/..; cloth extra, \s. lod. ■, • -^ \ VERS DE SOCI]&Til. Golden Gleanings from Poets of the Nineteenth Century : Tennyson, Browning, Swinburne, RossETTi, Jean Ingelow, Hood, Lytton, and very many .others. Edited by H. Cholmondeley-Pennell, Author of ' ' Puck on PegSf , sus." Beautifully printed, and bound in cloth, extra gilt, uniform with the " Golden Treasury of Thought." "js. (>d. {Nearly ready. Golden Treasury of Thought. The Best Encyclopsedia of Quotations and Elegant Extracts, from Writers of all Times and all Countries, ever formed. Selected and Edited by Theodore Taylor, Author of "Thackeray, the Humourist arid Man of Letters," "Story of Charles Dickens' Life." CrovirnSvo, very handsomely bound, cloth gilt, and gilt edges, yj. dd. *** An attempt to put into the hands of. the reader and student a vtore varied and cowtplete collection of the best thoughts of the best authors than had before been made. It is not everybody who can get the original wor^s from which the extracts are taken, while a book such as this is within the reach of all, and can- not be opened without finding something worth reading, and in most cases worth rememi/erins. 74 <5^ yt,,' PICCADILLY, LONDON, W. BOOJCS PUBLISHED BY CHATTO ^ WIND US. The Great Conde, and the Period of the Fronde : An Historical Sketch. By Walter FitzPatrick. Second' Edition, in 2 vols. 8vo, cloth extra, 15^. "A very agreeable, trustworthy, and readable sketch of a famous man." — StandartL. " Mr. FitzPatrick has given us a history that is pleasant to read : his style is incisive and picturesque as well as fluent. The work is well done, historically and morally." — Tablet, ** The sketches of the characters and careers of the extraordinary men and women who lived, intrigued, governed, or strove to govern, are admirable for their life- iikeness.'* — Morning Post. Greenwood's (James), Wilds of London. With a Full Account of the Natives : being Descriptive Sketches! from the Personal Observations and Experiences of the "Writer, of Remarkable Scenes, People, and Places in London. By James Greenwood, the "Lambeth Casual" Crovm 8vo, cloth, extra gilt, v\rith Illustrations, 6f. \_Prefaring. Grose's Dictionary of the Vulgar Tongue. 1785. A genuine unmutilated Reprint of the First Edi- tion. Quarto, bound in half-Roxburghe, gilt top, price 8,f. •.• Only a small number of copies of this very vulgar^ but very curious^ look have been printed, for the Collectors of " Street Words" and Colloquialisms. Companion to "The Secret Out." Hanky-Panky. A New and Wonderful Book of Very Easy Tricks, Very Difficult Tricks, White Magic, Sleight of Hand ; in fact, all those startling Deceptions which the Great Wizards call " Hanky-Panky." Edited by W. H. Cremer, of Regent Street. With nearly 2CXJ Illustrations. Crown 8vo, cloth extra, price 4^. dd. Hatton's (Jos.) Kites and Pigeons. A most amusing Novelette. WithlUustrationsbyLlNLEY Sambourne, of "Punch." Fcap. 8vo, jliustrated vfrap- per, l^. Hawth orne's English and American Note Books. Edited, with an Introduction, by Moncure D. Conway. , Royal l6mo, paper cover,, \s.; in cloth, \s. bd. 74 d. ' ■'■' '■ Hbgarth's Five Days' Frolic; or, Pere- grinations by Land and Water. Illustrated with Tinted Drawings, made by HoGARfH and Scott during the Journey, '4to, beaujifi^y: ■prioted, cloth, extra gilt, lew. 6<^. ' "''";■ •** -^^ graphic and most extraordinary picture of the hearty English times in which these merry artists lived, 74 <&» 75, PtC'eABIt^Y, LONDON, W. 24 BOOJCS PUBLISHED BY CHATTO &• WINDUS. OLIVER WENDELL HOLMES' WOEKS. Holmes' Autocrat of the Breakfast Table. An entirely New Edition of this Favourite Work. Royal l6mo, paper cover, u.j in cloth, neat, is, bd. Holmes' Poet at the Breakfast Table. From January to June. Paper cover, is. Holmes' Professor at the Breakfast Table. A Companion Volume to the " Autocrat of the Breakfast Table." Royal i6mo, paper cover, is. ; cloth neat, l.f. (>d. Holmes' Wit and Humour. Delightful Verses, in the style of the elder Hood. Fcap. 8vo, illustrated ; wrapper, is. Hood's Whims and Oddities. The Entire Work. Now issued Complete, the Two Parts in One Volume, ; with all the Humorous Designs. Royal l6mo, paper cover, is. ; cloth neat, is. 6d, Hunt's (Leigh) Tale for a Chimney CornePi and other charming Essays. With Introduction byEDM^u^pc Ollier, and Portrait supplied by the late Thornton HuSy. ' Royal l6mOj paper cover, is. /^. ; cloth neat, is. lod. '^ "'Y Hunt's (Robert, F.R.S.) Drolls of Old Cornwall ; or; Popular Romances of the West of Engt LAND. New Edition, Complete in One Volume, with Illustra- tions by George Cruikshank. Crown 8vo, extra cloth gilt, •js. dd. _ •,* " Mr. Hunt's charming book on the Drolls and Stories of the West V- England." — Saturday Review. Josh Billings: His Book of Sayings. With Introduction by E. P. Kingston, Companion of Artemus Ward when on his " Travels." Fcap. 8vo, illustrated cover, is. 74 d- 7S, PICCADILLY, LONDON, W. BOOKS PUBLISHED BY CHATTO dr- WINDUS. 25 Jennings' (Hargrave) One of the Thirty. With curious Illus- trations. Crown 8vo, cloth extra, \os. ()d. *•* An extrnordinary narrative, tracing down one of the accuried fieces of silver/orwhich yestis of Nazareth was sold. Through eighteen centuries is this fated coin tracked, now in the possession of the inyiocent, now in the grasp of the guilty, but every- vuhere carrying with it the evil thatfetlufokyudas. Jennings' (Hargrave) The Rosicrucians : Their Rites and Mysteries. With Chapters on the Ancient Fire and Serpent Worshippers, and Explanations of the Mystic Ss^nbols represented in the Monuments and Talismans of the Primeval Philosophers. Crown 8vo, cloth extra, with about 300 Illustrations, 10.1-. 6d. Jerrold's (Blanchard) Cent, per Cent. A Story Written on a Bill Stamp. A New Edition. Fcap. 8vo, illustrated boards, 2s, [N'early ready. Kaiendars of Gwynedd. Compiled by Edward Breese, F.S.A. With Notes by William Watkin Edward Wynne, Esq., F.S.A., of Penairth.' Demy 4to, cloth «xtra, 28j-. The Knowing Ones at Home. Stories of their Doings at a Local Science Meeting, at the Crystal Palace, at St. Paul's, at a Foresters' Fgte, &c., &c. A New ■and entirely Original Hu- morous Story, crammed ■with Fun from the first l^e to the last. Pro- fusely Illustrated by Brunton, Matt Mor- gan, and other Artists. Fcap. 4to, illustrated wrapper, price \s. 74 d.; or, Large-paper Copies (a limited number only printed), price 2is. Life in London ; or, The Day and Night' Scenes of Jerry Hawthorn and Corinthian Tom, With THE WHOLE OF CrUIKSHANK'S VERY Droll Illustrations, in Colours, after the Originals. Crown 8vo, cloth extra, "js. fid. . < , . , . . , •*• One of the mosifopuldr looks\ez'er isiwedy and often quoted by Thackeray, who devotes one of his "Roundabout Papers" to_U-description of it. 74 &' 7S> -P^CCAD/ZLV, LONDON, W. BOOKS PUBLISHED BY CHATTO &> WINDUS. 27 Literary Scraps. A Folio Scrap-Book of 340 columns, with guards, for the reception of Cuttings from News- papers, Extracts, Miscellanea, &c. A very useful book, , In folio, half-roan, cloth sides. Is. 6d. Little Breeches, and other Pieces (Pike County Ballads). By Colonel John Hay. Foolscap 8vo, illus- trated cover, u. 6d. The Little London Directory of 1677. The Oldest Printed List of the Merchants and Bankers of London. Reprinted from the Rare Original, with an Introduction by John Camden Hott-en. l6mo, binding after the original, 6s. dd. Henry Wadsworth Longfellow's Prose Works, Complete, including his ~ Stories and Essays, " Outre-Mer," '"Hyperion^" "Kavanagh," "Drift- wood," " On the Poets and Poetry of Europe," now for the first time collected. Edited, with an Introduc- tion, by the Author of "Tennyson- iana." With Portrait apA Illustra- tions, drawn by Valentine W. Bromley. 800 pages, crown 8vo, cloth gilt, "js. 6d. * »* T&e reader vjilljind the present edition of ~yH^^^ ^ , . Longfellffu^s Prose Writings hy far the most "" ^r^Xfi^ - -..^^^^— eomplete ever issued in this couHiry. "Outre- '\ Mer" contains iwo additional chapters^ restored from the first edition; while " The Poets and Poetry of Eurofe," and the little collection of Sketches entitled " Driftwood^ are now first introduced to the English public. Lost Beauties of the English Language. An Appeal to Authors, Poets, Clergymen, and Public Speakers. By Charles Mackay, LL.D. Crown 8vo, cloth extra, 6s. 6d. Mad re N at u ra yersws The Moloch of Fashion. By Luke Lim- ner. With 32 Illustrations by the Author. Fourth Edition, revised and corrected. Cloth extra gilt, red edges,- price zs. 6ii. ■ ,.,,'■ \N early rmdy. "Agreeably written and amusingly illustrated. Common sense and erudition are broiight to bear on the subjects discussed in it." — Lancet. 74 <&= 75, PICCAB'ILLY, LONDON, W. ■ PUBLISHED BY CHATTO &> WINDUS. 5 of the Water Lily, during Three he Rhine, Neckan, Main, Moselle, Danube, Saone, and 7 R. B. Mansfield, B.A. Illustrated by Alfred , B.A. Fifth Edition, revised and considerably Enlarged. . cloth extra, gilt, 5^. 'OMP ANION TO "The Secret Out." Th gician's Own Book. Ample Ir ructions for Performances with Cups and Balls, Eggs, Hats, "kerchiefs, &c. All from Actual Experience. Edited by W. H. '.R^ of Regent Street. Cloth extra, 200 Illustrations, 4^. bd. wiagna Charta. ' An exact Facsimile of the Original Document, preserved in the British Museum, very carefully drawn, and printed on fine plate paper, nearly 3 feet long by 2 feet vride, vrith the Arms and Seals of the Barons elaborately emblazoned in Gold and Colours. A.D. 1215. Price Sj. ; or, handsomely framed and glazed, in carved oak, of an antique pattern, 22a (>d. A iiiU Translation, with Notes, has been prepared, price f>d. ENTIBELY NEW GAMES. ^^V The Merry Circle, and How the Visitors were entertained during Twelve Pleasant Evenings. A Book of New Intellectual Games and Amusements. Edited by Mrs. Clara Bellew. Crown 8vo, numerous Illustrations, cloth extra, 4J. 6^. ••• A^ excellent hoek to consult hefm-e going to an evening party. 74 ar- 75, PICCADILLY, LONDON; W. BOOKS PUBLISHED BY CHATTO &= WINj. MARK TWAIN'S WORKS. AUTHOR'S CORRECTED EDITION. Mark Twain's Choice Works. Revist and Corrected by the Author. With a Life, a Portrait of the Authc and numerous Illustrations. 700 pages, cloth gilt, l5.J,d. Mark Twain's Inno- cents Abroad : The Voyage Out. CrpT*n 8vo, cloth, fine toned paper, Jf. dd.; or fcap. 8vo, illustrated wrapper, \s. Mark Twain's New Pilgrim's Progress : The Voy- ags Home. Crown 8vo, cloth, fine toned paper, 3J-. dd. ; or fcap. 8vo, illustrated wrapper, ij.] Mark Twain's Bur-, lesque Autobiography, First' Mediaeval Romance, and on Children. Fcap. 8vo, illustrated cover, 6(/. Mark Twain's Eye-Openers. A Volume of immensely Funny Sayings, and Stories that will bring a sniile upon the gruffest countenance. Fcap. 8vo, illustrated wrapper, is. Mark Twain's Jumping Frog, and other Humorous Sketches. Fcap. 8vo, illustrated cover, is. " An inimitably funny book." — Saturday Review, Mark Twain's Pleasure Trip on the Continent of Europe. (The "Innocents Abroad" and "New Pilgrim's Progress " in One Volume.) 500 pages, paper boards, 2s.; or in cloth, 2s. 6d. Mark Twain's Practical Jokes ; or, Mirth with Artemus Ward, and other Papers. By Makk Twain, and other Humorists. Fcap. 8vo, illustrated cover, is. Mark Twain's Screamers. A Gathering of Delicious Bits and Short Stories. Fcap. 8vo, illustrated cover, is. 74 6^ 75, PICCADILLY, LONDON, W. 30 BOOKS PUBLISHED BY CHATTO &^ WINDUS. Mayhew's London Characters : Illus- trations of the Humour, Pathos, and Peculiarities of London Life. By Henry Mayhew, Author of " London Labour and the London Poor," and other Writers. With nearly lOO graphic Illustrations. Crown 8vo, cloth gilt, about 5ckj pages, 6j-. Monumental Inscriptions of the West Indies, from the Earliest Date, with Genealogical and Historical Annotations, &c., from Original, Local, and other Sources. Illus- trative of the Histories and Genealogies of the Seventeenth Century, the Calendars of State Papers, Peerages, and Baronetages. With Engravings of the Arms of the principal Families. Chiefly collected on the spot by the Author, Capt. J. H. Lawrence- ARCHER. One volume, demy 4to, about 300 pages, cloth extra, 2\s, Mr. Brown on the Goings-on of Mrs. Brown at the Tichborne Trial, &c. Fcap. 8vo, illustrated cover, \s, Mr. Sprouts: His Opinions. Fcap. 8vo, illustrated cover, is. Uniform with "Tom D'Urfey's Pills." Musarum Deliciae; or, The Muses' Re- creation, 1656 ; Wit Restored, 1658 ; and Wit's Recreations, 1640. The whole compared with the originals ; . wiUi all the Wood Engrav- ings, Plates, Memoirs, and Notes. A New Edition, in 2 Volumes, post 8vo, beautifully printed on antique laid paper, and bound in antique boards, 2\s. A few Large Paper copies have been prepared, price 35^. ^ •** Of the Poets of the Restoration^ there are none whose works are more rare than those of Sir John Mennis aTid Dr. James Smith. Thesmall volume entitled ^^ Musaricjn Delicia ; or. The Muse^ Recreation " which contains the prodvctiofis of these two friends, was not accessible to Mr. Freejnan when he com^led his Kentish Poets," and has since become so rare that it is onlyfoundin the cabinets of the curious. A reprint of the *' Musarum Delicice,'* togetherwith several other kindred pieces of the period, appeared in i^xt, forming two volumes of PacetioBf edited by Mr. B.Dubois, authorof"The Wreath" Ss'c. These volumes having Tn tumbecome exceedingly scarce, the Publishers venture to put forth the'presentnetn edition, in which, ■while nothing has been omitted, no pains have been spared to render it more complete and elegant than any that has yet appeared. The type, plates, and woodcuts of the originals have been accurately followed ; the notes of the Editor of 1817 are considerably augntented, and indexes have been added, together with a portrait of Sir "John Mennis, fr07n apainting by Vandykein Lord Clarendon^s Collection. 74 &' 75, PICCADILLY, LONDON, W. BOOKS PUBASHED BY CHATTO &>. WmOUS. 31 The Mystery of Mr. E. Drood. An Adaptatiwi. By ,Orpheus C. Kerr. Fcap. .8vo, illustrated cover, IJ-, The Mystery of the Good Old Cause: Sarcastic Notices of those Members of the Long Parliament that held Places, both Civil and Military, contrary to the Self-denying Ordinahce of April 3, 1645 ; vfith the Sums of Money and Lands they divided among themselves. Small 4to, half-morocco. Is. 6d. Never Caught "in Blockade-Running. An exciting book of Adventures during the American Civil War. Fcap. 8vo, illustrated cover, is. Nuggets and Dust, panned out in Cali- fornia by DoD Grile. Selected and edited by J. Milton Sloluck. A new style of Humour and Satire. Fcap. 8vo, illustrated cover, is. •** If Ariem-us Ward may be considered the Douglas Jerrold, and Mark Twain the Sydney Smith of America^ Dod Grile will rank as their Dean Swift. ARTHUR O'SHAUOHNESSY'S POEMS. Music and Moonlight: Poems and Songs. By Arthur O'Shaughnessy, Author of " An Epic of Women." Fcap. 8vo, cloth extra, "js. bd. An Epic of Women, and other Poems. By Arthxjr O'Shaughnessy. Illustrated by J. T. Nettleship. Second Edition. Fcap. 8vo, cloth extra, ds. *' Of the fonnal art of poetry he is in many senses quite a master ; his metres are not only good,— they are his own, and often of an invention most felicitous as well as careful." — Academy. " With its quaint title and quaint illustrations, ' An Epic of Women ' will be a rich treat to a wide circle of admirers." — Athenaum. " Many of his verses are exceedingly beautiful ; like a delicious melody."^ JExaminer. ' ' '■ The Old Prose Stories whence Tennyson's "Idylls of the King" vpere taken. By B. M. Ranking. Royal i6mo, paper cover, is. ; cloth extra, is. 6d. 74 dp= 75, PfCCADILLY, LONDON, W. 32 BOOKS PUBLISHED BY CHATTO &■ WINDUS. Napoleon III., the Man of His Time; from Caricatures. Part I. The Story of the Life of Napo- leon III., as told by J. M. Haswell. Part II. The Same Story, as told by the Popular Carica- tures of the past Thirty-five Years. Crown 8vo, with Coloured Frontispiece and over loo Caricatures, 400 pp., "js. bd. *,* The object of this Work is to give Both Sides of^ the Story. The Artist has. ^one overthe entire j^ound of Continental and English Caricatures for the last third of a century^ and a^ very interesting book is the result. Original Lists of Persons of Quality ; Emigrants ; Religious Exiles ; Political Rebels ; Serving Men Sold for a Term pf Years ; Apprentices ; Children Stolen ; Maidens- Pressed ; and others who went from Great Britain to the American Plantations, 1600-1700. With their Ages, the Localities where they formerly Lived in the Mother Country, Names of the Ships in which they embarked, and other interesting particulars. From MSS. preserved in the State Paper Department of Her Majesty's Public Record Office, England. Edited by John Camden Hotten. a very handsome volume, crown 4to, cloth gilt, 700 pages, 3 1 J. dd. A few Large Paper copies have been printed, price 5or. 74 6^ 75, PICCADILLY, LONDON, W. BOOKS PUBLISHED BY CffATTO &» WINDUS. 33 THE OLD DRAMATISTS. Ben Jonson's Works. With Notes, Criti- cal and Explanatory, and a. Biographical Memoir by William GiFFORD. Edited by Lieut.-Col. Francis Cunningham. Com- plete in 3 vols., crown 8vo, Portrait. Cloth, 6j. each; 61oth gilt, 6j. 6i/. each. George Chapman's Plays, Complete, from the Original Quartos. With an Introduction by Algernon Charles Swinburne. Crown 8vp, Portrait. Cloth, 6j. ; cloth gilt, 6j-. (>d. {Nearly ready. Christopher Marlowe's Works: In- cluding his Translations. Edited, with Notes and Introduction, by Lieut.-Col. F. Cunningham. Crown 8vo, Portrait. Cloth, ds.; cloth gilt, ds. (>d. Philip Massinger's Plays. From the Text of Wm. GlFFORD. With the addition of the Tragedy of " Believe as You List." Edited by Lieut. -CoL Francis Cunning- ham. Crown 8vo, Portrait. Cloth; ds. ; cloth gilt, 6j. dd. Parochial History of the County of Cornwall. Compiled from the best authorities, and corrected and improved from actual survey. 4 vols. 4to, cloth extra, £,J, 3^. the set ; or, separately, the first three volumes, 16^. each ; the fourth volume, i8j. Companion to " Cussans' Heraldry.'' The Pursuivant of Arms; or. Heraldry founded upon Facts. A Popular Guide to the Science of Heraldry. By J. R. Planch^, Esq., F. S.A., Somerset Herald." To which are added. Essays on the BADGES OP THE Houses of Lancaster and York. A New Edition, enlarged and revised by the Author, illus- trated with Coloured Frontispiece, five full-page Plates, and about 200 Illustra- tions. Crown 8vO, beautifully bound in cloth, with Emblematic Design, extra gilt, 75. 60'. 74 &» 7S, PICCADILLY, LONDON, W. BOOKS PUBLISHED BY CHATTO &» WINDUS. Seventh Edition of uck on Pegasus. By H. Cholmondeley- Pennell. Profusely illus- trated by the late John Leech, H. K. Browne, Sir Noel Paton, John MiLLAis, John Tenniel, Richard Doyle, Miss Ellen Edwards, and other artists. A New- Edition (the Seventh), crown 8vo, cloth extra, gilt, price 5j. ; or gilt edges, 6j. *,* This most amitsing •work has received everywhere the highest praise as " a clever and brilliant book" '* The book is clever and amusing, vigorous and healthy." — Saturday Review. "The epigrammatic drollery of Mr. Cholmondeley-Pennell's * Puck on Pegasus* is well known to many of our readers. . .' . The present (the sixth} is a superb and hand- somely printed and illustrated edi 75, PICCADILLY, LONDON, W. BOOKS PUBLISHED BY CHATTO &= WINDUS. 35 "An Awfully Jolly Book for Parties." Pu n iana : Thoughts Wise and Otherwise, ^y the Hon. Hugh Rowley, Best Book of Riddles and Puns ever formed. With nearly 100 exquisitely Fanciful Drawings. Contains nearly 3000 of the best Riddles, and 10,000 most outrageous Puns, and is one of the most Popular Books ever issued. New Edition, small ^ ■ quarto, uniform with the -£v;^ " Bab Ballads." Price 6^. "" ** Enormous* burlesque — unap-) proachable and pre-eminent. We * think this very queer volume will be a favourite. We should suggest that, to a dull person desirous to get credit with the young holiday people, it would be good policy to invest in the book and dole it out by instalments, —^tf^x^tfoy Revieiu. By the same Author, A Second Series of Pun iana; Containing nearly 100 beautifully executed Drawings, and a splendid Collection of Riddles and Puns, fully equal to those in the First Volume. Small 4to, uniform with the First Series, cl. gt. , gt. ed ges, 6s.\_Preparing. Private Book of Useful Alloys and Memoranda for Goldsmiths and Jewellers. By James E. Collins, C.E. Royal l6mo, 3j. 6<^. Invaluable to the Trade. Uniform with "Wonderful Characters." Remarkable Trials and Notorious Characters. From "Half-Hanged Smith," 1700, to Oxford, who shot at the Queen, 1840. By Captain L. Benson. With spirited full-page Engravings by Phiz. 8vo, 550 pages, "js. 6d. %* A Complete Library of Sensation Literature I There arefilois enough here to produce a hundred" exciting^' Novels^ and at least Jive hundred "powerfiii'* Magazine Stories, The book will he appreciated by all readers whose taste lies in this direction. Uniform with "The Turf, Chase, and Road." Reminiscences of the late Thomas Assheton Smith, Esq.; or. The Pursuits of an English Country Gentleman. By Sir J. E. Earbley Wilmot, Bart. A New and Revised Edition, with Steel-plate Portrait, and plain and coloured Illustrations. Crown 8vo, cloth extra, 7j. 6d. 74 d. "Valuable as a. work of reference." — Saturday Review. A KEEPSAEB FOR SMOKERS. The Smoker's Text-Book. By J. Hamer, Exquisitely printed from "silver-faced" type, cloth, very r.R.S.L. neat, gilt edges, 2s. td. , post free. 74 ellum, vary frotn eight to nine inches in length — some in armour, and some in robes of state. In addition to these are Portraits of an A rchbishopinfull canonicals, of a Chancellor, and of many of the chief Burgesses of the City of Waterford, as well as singularly curious Portraits of the Mayors of Dublin, Wnterford, Limerick, and Cork, figured for the most part in the quaint bipartite costuTne of the Second' Richard's reign, though partaking of many of the peculiarities of that of Edward III. A Itogether this ancient work of art is unique of Us kind in Ireland, and deserves to be rescued from, oblivion, by the Publication of the unedited Charters, and of facsimiles of all the Illuminations, The production of such a work would throw much light on the question of the art and social habits of the Anglo-Norman settlers in Iceland at the close of the fourteenth century. The Charters are, many of them., highly important from- an historic point of view. The Ilhaninations have been accurately traced and coloured for the vDorkfrom a coPy carefully ■made, by permission of the Mayor and Corporation of Waterford, by the late George V. Du Noyer, Esq., M.R.I. A. ; and those Charters which have not already appeared in print will be edited by the Rev. James Graves, A.B., M.R.I. A., Hon. Sec. Kilkenny and South-East of Ireland Archesological Society. The work will be brought out in the best m.anner, •with embossed cover and characteristic title-Page / and it will be put to Press as soon as 250 subscribers are obtained. The Price, in imperial \to, isios. to subscribers, or^os. to non-subscribers. Wonderful Characters : Memoirs and Anecdotes of Remarkable and Eccentric Persons of Every Age and Nation. From the text of Henry Wilson and James Caulfjeld. Crown 8vo, cloth extra, with Sixty-one full-page Engravings of Extraordinary Persons, "js. dd. ' •#* There are so many curious ^natters discussed in this volume, that any pel" son who takes it up will not readily lay it down until he has read it through- The Introduction is almost entirely devoted to a consideration of Pig-Faced Ladies, and the various stories concerning them. . . Wright's (Andrew) Court-Hand Re- stored ; or. Student's Assistant in Reading Old Deeds, Charters, Records, &c. Half Morocco, a New Edition, loj. 6d. •,* The best guide to the reading of old Records,