SB 191 L41 m^T* >^^->^. :^> ^i.■ #■. -^.^ ^^>^ 1 1 f\ ALBERT R. MANN LIBRARY New York State Colleges OF Agriculture and Home Economics AT Cornell University Cornell University Library The original of tiiis book 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/cu31924003370586 ON SOME POINTS IN THE COMPOSITION OF WHEA.T-GMIN, ITS PEODUCTS IN THE MILL, AND EEEAD. BT J. B. LAWES, F.K.S., F.C.S, jlnd J. H. GILBERT, Ph. D., F.C.S. LONDON: I'RINTEI) BT HAEEISOK AND SONS, ST, MARTIN'S LANE, W.C. 185!;, ON SOME POINTS IN THE COMPOSITION OF WHEAT-GRAIN, ITS PEO- DUCTS IN THE MILL AND BEEAD, By J. B. LAWES, P.E.S., F.C.S., and J. H. GILBERT, Ph. D., F.C.S. The composition of the grain yielding the most important article of human food in temperate climates^ its yield of valuable products, and the varying composition either of the grain itself, or of these products, according to the conditions of growth, or the circum- stances of after preparation, are subjects worthy the attention equally of states and of men of science. Accordingly we find, that a chemical examination of wheat-grain and its products, has from time to time been undertaken by chemists of repute ; sometimes as a matter of private investigation, and at others of public inquiry .; and almost as numerous as the names of the experimenters, are the special lines of research which they have selected. We are indebted to Beccaria for the first notice, more than a century ago, of the gluten in wheat. Among the earlier investi- gators of the subsequent period, are, Proust, Vauquelin, De Saussure and Vogel, who have examined the proximate principles, and some of the changes to which they are subject, in various descriptions of wheat, of flour, or of bread. M. Bous- singault has somewhat elaborately studied various branches of the subject more recently; and we are indebted to Dumas, B 2 LAWES AND GILBERT Payen, Jolinston, and Dr. R. D. Thomson for original, as well as a considerable amount of collected information. The most recent; on some points the most detailed, and from advance m methods, perhaps on some also the most rehable, are the results ofM. Peligot in 1S49, on the proximate constitution of various kinds of wheat, and of M. Mi lion in 1849 and 1854, on some- what similar points. Lastly, in 1853 M. Poggiale, and in 1855 Dr. Maclagan, have given the results of their investigations on the characters and composition of bread. Besides these more general investigations, we have had in recent times many special inquiries connected with our subject. Thus, M. Boussingault has given us analyses of the ashes of wheat ; and many other such analyses have been made in Ger- many, and elsewhere, since the first appearance, in 1840, of Baron Liebig's work on "Chemistry in its Applications to Agriculture and Physiology." In this country, Mr. Way has given us the most extensive series of wheat-grain-ash analyses, his list including those of 26 specimens or descriptions. The plan of our own investigation, which unfortunately has been much less perfectly filled up than we at first intended, was entered upon more than a dozen years ago, and was devised with reference to the following points : — 1st. The influence of varying characters of season, and of vari- ous manuring, upon the organic and mineral composition of wheat grain. 2ndly. The characters of varieties, especially in relation to their adaptation, and the qualities they then develop, under the influence of broader distinctions as to locality, altitude, latitude, and vary- ing climatic circumstances generally. It is in the second branch of the inquiry that we have fallen the furthest short of our intentions. With a view to its prosecution, a journey through the chief corn growing districts of Europe, com- mencing at the northernmost point at which wheat is grown suc- cessfully, was about to be undertaken in 1848; but the social dis- turbances on the continent at that period, necessarily prevented it. The plan proposed was — to collect information, as to the geological and meteorological characters of the various localities, as to the mode of culture, and as to the general acreage yield, both in straw and grain ; and lastly, to procure characteristic specimens for chemical examination at home. Failing entirely in the execution of this design, the Exhibition of 1851 was looked forward to as an oppor- ON THE COMPOSITION OF WHEAT-GRAIN, &0. 3 tunity for procTiring spepimens not only of wheat, but of other vegetable products, and perhaps also important particulars of their growth, from various countries and climates. Such, however, was the division of authority, and such the alleged preference given to public institutions in such matters, that, whether the latter bene- fited or not, the collection which we, as private individuals, were enabled to make, was entirely inadequate to our object. From these difficulties it is, that our second main object of inquiry was necessarily to a great extent abandoned ; and chiefly for this rea- son, but partly owing to the pressure of other subjects ; the first or more limited or local branch of the investigation has in recent years been but imperfectly followed up. And, as it is probable that it must for some time remain so, it has been thought desirable thus to put on record the results already obtained ; hoping that they may serve the double purpose, of confirming or adding to previously existing knowledge, and of indicating to others ■ the points most requiring further study. The following is a brief outline of the plan of investigation which has yielded the results which we have now to lay before the Society. From the season 1843-4, up to the present time, wheat has been growing in the same field continuously, both without manure, by ordinary, and by various chemical manures. As a general rule, the same description of manure has succeeded year after year on the same plot of land. The amount of produce, corn, straw, and chaff, and its characters as to weight per bushel, &c., have in every case, been carefully ascertained and recorded. Samples from each plot — ;both grain and straw^— have also been collected every year. Of each of these samples two weighed por- tions are coarsely ground ; the dry matter determined at a tempera- ture of 213° ; and the ash by burning on sheets of platinum, in cast iron muffles arranged for that purpose.* Other weighed por- tions of grain and straw are partially dried, so as to prevent their decomposition ; and in this state they are preserved for any exami- nation of their organic constituents. By this course of procedure, ,a vast mass of results has been obtained, illustrating the influence of season and manuring, upon the percentage of dry substance, and of mineral constituents, in the produce. In selected cases, the nitrogen in the grain, and in the straw, has been determined. * The dry matter and ash, were not determined In such complete series in the earlier years, as, ia the later. b2 4 LAWES AXD GILBERT A summary table of these dry matter, ash, and nitrogen results, will be given below. In from twenty to thirty cases complete analyses of the grain-ashes have been made, and the results of these will be given in full. Besides the experiments above described, in selected cases, chiefly from the produce of the earlier years of the field experi- ments, it was sought to ascertain the comparative yield of flour, and also the characters of the flour, of grain grown by different manures in the same season, or by the produce of different sea- sons. The colonist's steel handmill was first had recourse to for this purpose. But it was soon found, that it was extremely diflS- cult so to regulate the machine, as to secure uniform action upon the difl^erent grains ; and it was further found, that the grain, and especially the bran, was cut up rather than crushed, so as to leave too much of fiour in the portion separated as bran, and too much of . bran in that separated as flour ; and hence the results were not sufficiently comparable with those of the ordinary mill, Arrange- iQcnts were therefore made for prosecuting the inquiry at a flour mill in the neighbourhood, worked by water power. Weighed quantities of the selected samples (from 125 to 250 lbs. each), were passed through the stones, and the " meal" thus obtained, through the dressing machine, under our own personal superintendence ; great care being taken to clear from the diff'erent parts of the apparatus the whole of one lot, before another was commenced upon. The yield in the dressing machine of each of the diflferent products was ascertained, and its percentage in relation to the total grain or its " meal," has been calculated. Portions of each of these products have had their drj^ matter (at 212°), and their mineral matter (by burning on platinum), determined. The per- centage of nitrogen in a few selected series — from the flnest flour down to the coarsest bran — has also been estimated ; and in the same cases, the amounts of one or two of the more important constituents of the ash have also been determined. The results of these dry matter, ash, >> ''"^"-gen, and constituent of ash deter- minations, in the series of diflerent products obtained in the mill, will be given in tables further on. The original design, was to complete the examination of the mill products, by determining in several series cf them, the per- centage of each of their proximate organic principles ; and also the amount and composition of mineral matters, associated with ox THE COMPOSITION OF WHEAT-GEAINj &C. 5 them respectively. It was hoped, by this latter inquiry, to; obtain, important collateral information, bearing upon the influence of various constituents upon the healthy and special development of the plant. Although, however, specimens of the flour are pre- served for this purpose, as well as the ashes of each crude pro- duct, it is feared that this subject cannot be proceeded with, at least for a considerable time to come. Portions of the different products of the dressing machine (including more or less of the finest flour, of the more granular, or of the more branny particles respectively), from grains of somewhat various history of growth, have been experimented upon to ascertain their comparative bread-making qualities ; and these results, together with a few examinations of baker's bread, and a discussion of the results of other experimenters, as to the yield of bread from a given amount of flour, and the percentage of water and of nitrogen in the former, will be given below. With this short outline of the plan of investigation which has been pursued, we proceed now to a discussion of the results which have been obtained. In Table I. are given, in the first four columns, certain pro- minent characters of the produce of each of ten years of the suc- cessive growth of wheat as above described. The items are : — The total produce per acre (corn and straw), in lbs. ; The per cent, of corn in the total produce ; The per cent, of dressed corn in the total corn ; and, The weight per bushel of dressed corn in lbs. The figure given for each year, generally represents the average of about 40 cases; and the characters enumerated are the best which can be given in a summary and numerical form, to indicate the more or less favourable condition of the respec- tive seasons for the healthy development of the crop, and the perfect maturation of the grain. In the second set of three columns are given, side by side with the general characters just described, the percentages in the grain of each year — Of dry substance ; Of ash in dry substance ; and. Of nitrogen in dry substance ; the two former items being in most cases the average of 30 to 40 cases in each year; but the per cent, of nitrogen, is in each instance, the mean of a few selected cases only. LAWES AND GILBEET In the third set of three columns, are given similar particu- lars relating to the composition of the straw. The percentages of dry substance and of ash in the straw, are however not the averages of so many cases in each year, as are those for the corn ; and the determinations of nitrogen in the straw, have also been made in fewer cases than in the grain. It will thus be seen, that the table affords a summary view of a really enormous amount of experimental result, and we ought to be able by its means to discover, at least the broad and characteristic effects of varying seasons, upon the compo- sition of the crop.* This indeed is all we could hope to attain, in such a mere outline and general treatment of the subject as is appropriate to our present purpose. TABLE I. General Summary. Particulars of the Frodace. Composition of Gaain. Composition of Straw. Total Per cent. Weight corn and Per cent. dressed per bushel of dressed Per cent. Per cent Per cent. Per cent. Percent. Percent. Harvests straw per acre corn in total com m total dry aeh in nitrogen dry ash in nitrogen in lbs. produce. com. corn in lbs. (212°) dry. in dry. (212°.) dry. in dry. 1845 5645 33-1 90-1 S6-7 80-8 1-91 2-25 7-06 0-92 1846 4114 43-1 93-2 63-1 84-3 1-96 2-15 ,i 602 0-67 1847 .5221 36-4 93-6 62-0 2-30 .. 6-56 0-73 1848 4517 36-7 89-0 68-5 80-3 202 2-39 .. 7-24 0-78 1849 5321 40-9 96-5 63-5 83-1 1-84 1-94 82-6 6-17 0-82 1860 5496 33-6 94-3 60-9 84-4 1-99 2-15 84-4 5-88 0-87 1851 5279 38-2 92-1 62-6 84-2 1-89 1-98 84-7 6-88 0-78 1852 4299 31'6 92-1 56-7 83-2 2-00 2-38 82-6 6-53 0-79 1853 3932 25-1 85-9 50'2 80-8 2-24 2-35 81-0 6-27 1-20 1854 6803 35-8 95-6 61-4 84-9 1-93 2-14 83-7 5-08 0-69 Means 5053 • 36-4 92-1 59-6 82-9 1-98 2-20 83-2 6-17 0-82 Leaving then out of view all minor points, and confining our- selves to our already defined object — namely, that of ascertaining the general direction of the influence of variation of season upon the composition of the wheat crop — we cannot fail to see, that wherever the three items indicating the quality of the produce * It should be stated, that up to 1848 inclusive, the description of wheat was the Old Bed Lammas ; from 1849 to 1852 inclusire, it was the Bed Cluster, and since that time the Eostook. The variations, according to season, both in the characters and composition of the pToducei, arc, however, very marked *ithin the period of growth of each separate description. ON THE COMPOSITION OF WHEATtGKAIN, &0. 7 markedly distinguish the crop as favourably developed, we have a general tendency to a high percentage of dry substance, and to a low percentage both of mineral matter, and of nitrogen, in that dry substance. This generalization is more especially applicable to the grain > but with some exceptions, mostly explicable on a detailed consideration of the circumstances and degree of its deve- lopment^ it applies to a great extent to the straw also. Let us take in illustration the extreme cases in the table. The seasons of ,1846> 1849, and 1851, with in the cases of the two latter large produce .also, give us the best proportion of corn in total produce, more than the average proportion of dressed corn in total com, and the highest weight per bushel — a very significant character. With this cumulative evidence as to the relatively favourable development and maturation of these crops, we find the grain in two of the cases, to be among the highest in percentage of dry matter ; and in the third (1849), though not so high as we should have expected, it is still above the average. The per- centages of mineral matter and of nitrogen in the dry substance of the grain, are at the same time, in these three cases, the lowest in the series. The seasons of 1850 and 1854 again, with large amounts of produce, yielded also very fairly developed grain ; and coincidently they afford a high percentage of dry substance, and lower percentages both of mineral matter, and of nitrogen, in that dry substance, than the cases of obviously inferior maturation. With some exceptions, it wiU be seen, that the straws also of these 5 betier years, give a tendency to low percentages both of mineral matter and of nitrogen in their dry substance- Turning now to the converse aspect, the season of 1853, shows itself in the general characters of the produce, to have been in every respect the least favourable to the crop ; and it ishould be added that in this instance (as well as in 1845 to which we shall next refer), the seed was not sown until the spring. In 1853 the produce of grain was small as well as very bad in quality ; and with these characters, we have in thd grain nearly the lowest per- centage of dry matter, and the highest percentage of ash and of nitrogen in that dry matter. In the straw, too, the dry matter is low, the ash somewhat high, and. the nitrogen much the highest in the series. In 1845, another year of spring-sowing, and at the same time of very bad quality of produce, we have nevertheless a large amount of growth ; a fact vrhich tends to explain some of the differences in compositioii £|.s. gcijnpared with 1853. Thus, 1845 8 LAWES AND GILBERT gives US low percentage of dry matter, but riot very high, either ash or nitrogen, in the grain. The straw, however, gives high per^ centages both of ash and of nitrogen; it being in the latter point next in order to 1853. The seasons of 1848 and 1852 again show low characters of produce. The former has coincidently the lowest percentage of dry matter in the grain in the series ; and both have high percentage of ash and nitrogen in the dry sub- stance of the grain. In the straw, the ash is in 1848 the highest, and in 1853 above the average; the nitrogen in dry matter of straw being however in neither instance high. In several of the cases here cited, there are deviations from our general assumption on one point or other. But an examination, in greater detail, would in most or all of them clear up the appa- rent discrepancy. When indeed, we bear in mind how infinitely varied was the mutual adaptation of climatic circumstances to stage of growth of the plant, in almost every case, it would indeed be anomalous, did we not find a corresponding variation on some point or other, in the characters or composition of the crop. Still, we have the fact broadly marked, that within the range of our own locality and climate, high maturation of the wheat crop is, other things being equal, generally associated with a high percentage of dry substance, and a low percentage of both mineral and nitro- genous constituents. Were we, however, extending the period of our review, and going into detail as to varying climatic circum-. stances, interesting exceptions could be pointed out. It may be observed in passing, that owing to the general rela- tionships of the amounts of corn to straw, and the generally coin- cident variations in the percentages of nitrogen in each, the tendency of all these variations is in a degree so to neutralize each other, as to give a comparatively limited range of difi'erence in the figures, representing for each year, the percentage of nitrogen in the dry substance of the total produce — corn and straw together. The tendency of maturation, to reduce the percentages of mineral matter, and frequently of nitrogen also, is not observable in corn crops alone. We have fully illustrated it in the case of the turnip ; and our unpublished evidence in regard to some other crops, goes in the same direction. The fact is indeed very important to bear in mind ; for it constitutes an important item in our study of the variations which are found to exist in the composition both of the organic substance, and of the ash, of one and the same crop, grown under different circumstances. We may particularly observe, ON THE COMPOSITION OF WIIEAT-GUAIN, &Ci S that the obvious reduction in the percentage of nitrogen in wheat- grain, the more, within certain climatic limits, the seed is perfected, is in itself a fact of the highest interest j and it is the more so, when we consider how exceedingly dependent for full growth, is this crop upon a liberal supply of available nitrogen within the soil. Bearing in mind, then, the general points of relationship which have been established between the characters of the crop as to development and maturation on the one hand, and the percentage amounts of certain constituents on the other, let us now see — ^what is the general influence of characteristic constituents of manure, upon the characters and composition of our wheat crop, which is allowed to remain on the land until the plant has fulfilled its highest function — namely, that of producing a ripened seed ? In illustration of this point we have arranged in Table III, the same particulars as to general character of the crop, and as to the composition of the produce, from several individual plots during the ten years; instead of the average of the series in each year, as in Table I. The cases selected for the comparison are : — 1. A continuously unmanured plot ; 2. A plot having an excess of ammoniacal salts alone every year; 3. The average of several plots, each having the same amount of ammoniacal salts as the plot just mentioned, but with it, a more or less perfect provision by manure, of the mineral con- stituents also. It would be impossible to give the detail supplying all the results collected in this Table III ; but perhaps it is only proper that we should do so, so far at least as the percentage of nitro- gen in the dry substance of the grain is concerned. 10 LAWE8 AND GILBERT TABLE II. Determinations of Nitrogen per Cent, in the Dry Matter of Wheat Grain grown at Rothamsted. EXPEKIMBNTS. Harvests 1 2 3 i 5 Meau, TJnmaniired. 1845 2-28 2 '21 2-33 2-30 2-28 1846 2-11 2-12 .. , , 2-11 1847 2 11 2-08 2-22 2-22 2-16 1848 2-33 2-34 2-32 2-37 2-34 1849 1-85 1-83 1-91 .. 1-86 1850 2 07 210 2 07 2-08 .1851 1-80 1-74 1-89 1-76 1'80 1«52 2-31 2-23 2-33 2-31 2-31 1853 2-26 2-33 2-38 2-32 1854 2-06 2-06 1-98 1-96 2 01 Manured with Ammoniacal Salts only. 1845 2 18 2-29 2-22 2-23 2-23 1846 2 18 2-12 2-29 2-19 2 19 1847 2 36 2-29 2-42 2-32 2-34 1848 2 39 2-41 2 39 2-49 2-42 1849 1 89 2 04 1-92 1-95 1860 2 13 2-08 2-19 213 1851 2 15 2 12 2-09 2-25 2 15 1862 2 41 2-50 2-44 2-58 2 48 1853 2 43 2-48 2-37 2-44 2-43 1854 2-31 2-22 2-31 2 37 2-30 Manured with Ammoniacal Salts and Mineral Manure. (Mixed Plots.) 1845 1846 2-20 2-14 2 14 2 16 1847 2-34 2-38 2-40 2-42 2-44 2-40 1848 2-36 2-40 2-42 2-48 2-41 1849 1-96 1-97 2-10 2-07 2-02 1860 2-16 2-28 2-25 2-25 2 23 1861 2 00 1-98 2-02 1-92 1-98 1852 2-43 2-34 2-31 2-40 2-32 2-36 1853 2-30 2-34 2-29 2-28 2-30 1854 2-16 •• 2-12 2-07 •• 2-12 ON THE COMPOSITION OF WHEAT-GEAIN, &C. 11 It is necessary to make a few remarks in reference to this Table of more than one hundred nitrogen determinations. They were made by the method of burning with soda-lime, and collecting and weighing as platinum salt in the ordinary way. Few, perhaps, who have only made a limited number of such determinations, then only on pure and uniform substances, and who have not attempted to control their work at another period, with fresh re-agents, or by the work of another operator, will imagine the range of variation which is to be expected when all these adverse elements are to have their influence. It is freely granted, that the variations shown in the Table between one determination and another, on one and the same substance, are sometimes more than could be desired. The following, however, are the circumstances under which they have been obtained. Experiments 1 and 3 were pretty unifortaly made by the same operator, but not all consecutively, or with the same batch of re-agents. It was thought, therefore, that inde- pendently of .any variations between the two determination^, it would be desirable to have results so important in their bearings, verified by others. Accordingly, samples of each of the ground grains were given under arbitrary numbers, to two other operators, and their results are recorded respectively in columns 3 and 4 ; and where a fifth determination is given, it is a repetition by one or other of the experimenters last referred to. We should observe, that we have found it almost impossible to procure a soda-Hme that will not give more or less indication of nitrogen when burnt with an organic substance not containing it ; and hence we have at length adopted the plan of mixing 1-2 per cent, of non-nitro- genous substance intimately with the bulk of soda-lime, igniting it in a muffle, moistening, and reheating it gently. After this treatment the soda-lime is free from ammonia yielding matter. It should further be remembered, that a ground wheat-grain is by no means an uniform substance. Indeed, as we shall show further on, some of the particles of which such a powder is com- posed, may contain half as much again of nitrogen as-others ; and thus any inefficiency in the grinding, or error in taking the por- tion for analysis, may materially affect the result. Notwithstand- ing all these circumstances, and the admittedly undesirable range of difference in the several determinations in some cases, it wiU be observed, that generally three at least of the numbers agree sufficiently closely, and in some cases the fourth also. In fact after all, a study of the detailed table, must give considerable confidence, at least in the direction of the variations between the mean results given in Table III, and in their sufficiency for the arguments founded upon them. With these remarks on the data, let us proceed with the discussion of Table III itself, which next follows ; 12 LAWES AKD GILBERT M ffl •s lis- -omiuy ij 6[iij"ainp5 s e s o o o s s s is o o ? 8 o ^ O ■Xl«o o C^ ^ Ct

6 O r-l 6 o •s;iBS poem » ? 9 »0 in i>. Sj & § lo in nfl ID iffl OS □o us •X[UD s;|Bs ]BOB;nouiniv »U3 «S ^ r ? o in in in i -*< £ •pajnuEmufi lO 00 O rH 00 O* Ol t^ t>. t- to U3 to ■BlI^S IK3BIU *? "?* T** 00 CO 03 to M (-H OD w OD •iC[UO Bjp3g iBDBiuoramv Oa t-. OS V3 a> 00 00 CO s 00 •psmuBrann : : : f^ «3 ep M M -fl OD CO M r-t 00 CO CO SS 00 a 5 a ■s 5 ■siiBS iBawia -oraniv 5S BlBJanipi S S 5 M « ©1 g S S « « ^ « at CI ■X]UO fl1]BS iBSBUiotaniy ? ? * e* e» e» g s s F^ Ot C4 o CO to Ci •pajnuBoiufi s s s Ot Ol Cf «0 00 O 00 O CO »1* e* — CO CO 9 CO I'll- 1 •- •SllBS IBOBia •oramv 38 s[Bjau!W o <-• r-i rH t- 00 O CO l-l « f-* 9 •A\UQ S1FS iBSBiuonnny 00 : o —1 ■ (S e: g g I-H « ?■ ip •pajnuBiaufl. » S : 3 ? 9 ? Al C* r-t i-H Dl rH ua s cq It? BIIHS IGO«m -ommy i^ siBJaurpf Ci 00 * 00 9 ■? 9 OO OO 00 in OS CO O 00 00 k OS S5 •Aim BiiBg yB3Bmommy o o 00 00 ' 00 t» CO >« 00 00 00 00 3 9 CO OO ■paanuBnniji C4 53 s • ■ ri CO -^ CO CO 00 to r^ 00 CO CO OS "o Weiglit Per Biiahcl of Dressed Corn. lbs. •fi?lBg [BOBIII : r-t n t- m cq QD CO «0 U3 t- CI CD OO i-i m «) to so •a c» OS 3 ■X[U0 siiBg [Bouiuouimy « IC l-H i s s » C4 O M O .^ O <0 CO OS CO m CO 9 00 •psjnuBmufi U3 t- O CO CO O I-- «D o in ■^ O r-H s § s ^ OS cio lO MS ^ CO g Per Cent. Dressed Cora in Total Com. -omiuy ig s[BabajK «p r^ CO OS 0» 00 ■* CM CO § s s r-H US R« CS OS CO to 00 ■i^uo si^Bg iB3Biuoairay o ryH rH OS at Oi O} 00 « O S 3 g to n* o OS CQ , k ■pamnBranfi t^ «> 00 a !=! <» da o> OD f-l to i_0 Q3 I'o oa 0» OS OO OS CO O ■* OS t^- Cs to i4 |5| •B^lBg IBOBia -ouituy ^ BiBiaujK : ^ o wa « «s O lO 04 r^ Q CO OO ^ CO CO tO CO £ ! CO •ijuo B^iBg I'HDBinouiray CO CM r-l O ^ & g oa ao cp Ol A OS '^ CO so I-H 00 8 S3 l-H k "paittiiBiuufi CO ■* l-( t* :« & S « 00 o ^ k ^ OS to CO CO U3 II- |i Total Produce (Corn and Straw) per acre in lbs. ■B^IBS IBOBtU -onimy ap siBjanijij; t 1 § 1 1:1 i p CO 'iH , . i •^luo CO ill ci O to i s i 11' i 1 •pajnireniuxi m 51 III 3 s s s & & |g CO CO 1. 1 1 .1 S « g et CO, SS 9= 1 ON THE COJfPOStTldi^ ^P WHEAt-GBAIN, &C. 13 A glance at this Table III, shows that the quantity of produce varies very much indeed in one and the same season, according to the manuring. With these great differences in the quantities, dependent on manuring, we have far less marked differences in the quality of this ripened crop, dependent on the same causes ; and this, with some few exceptions, is the same whether we look to the columns indicating the general characters only, or the composition of the produce. That is to say, the same general distinctions between the produce of one season and another, are observable under the several varying conditions of manuring in each, as have been exhibited in the Table I of averages alone. In fact, season, or climatic variations, are seen to have much more influence than manuring, upon the character and composition of the crop. We have said that, other things being equal, the percentage of nitrogen in our wheat-grain was the lower the more the seed was perfected ; and we have also said, that nitrogenous manures greatly aid the development of the crop. But, an inspection of the columns of Table III which give the percentages of nitrogen in the dry substance of the grains produced under the three different conditions of manuring specified, shows us that there is almost invariably, a higher percentaige of nitrogen where ammo- niacal salts alone have been employed, than where the crop was unmanured. We also see that, almost invariably, there is a higher percentage of nitrogen where mineral manures as well as ammo- niacal salts have been used, than in the produce of the corre- sponding unmanured plots, A closer examination shows, however, though the indication is not uniform, that there is nevertheless, an obvious tendency to a lower percentage of nitrogen, where the mineral constituents also have been employed, than where the ammoniacal salts have been used alone ; and with this, there is on the average, a somewhat higher weight per bushel, indicating higher degree of maturation. Then, again, what are the circum- stances of these experiments, under which an increased percentage of nitrogen in the fixed substance of the produce, is obtained by a supply of it in manure ? The unmanured plot with its low per- centage of nitrogen in produce, is shown by the field experiments, to be greatly exhausted of the annually available nitrogen, relatively to the annually available mineral constituents required by the wheat crop. The plot, with the ammoniacal salts alone, is shown by the field results to be defective in the requisite and available minerals, relatively to the available nitrogen, and hence the crop 14 LAWES ANP ^ILBEET is grown under a rela,tive excess of the latter. Agaiii, the plots •with mineral manures and ammoniaeal salts together^ received so far an excess of the latter, as to yield, with the minerals, a larger crop than the average of the locality under rotation, and larger also, than the average of seasons would ripen healthily. It is then, under these artificial and abnormal circumstances, of the somewhat unnaturally low percentage of nitrogen, from obvious defect of it in relation to the developing and maturing capabilities of the season on the one hand, and the obviously relative excess of it on the other, that we got an increased percentage of nitrogen in wheat- grain by the use of it in manure. Even under these extreme conditions, the range of variation by manuring is very small ; and there is nothing in the evidence that justifies the opinion, that, within the range of full crops and healthy maturation, the per- centage of nitrogen in wheat grain, can be increased at pleasure by the use of it in manure. That very opposite extremes of condition of soil-supply, may directly influence the composition even of wheat-grain, is however, illustrated in the percentages of mineral matter, as well as those of nitrogen, given in the table. Thus, taking the mean results only, we have with the relative excess of mineral constituents on the unmanured plot, the highest per cent, in the produce; with the greatest relative defect on the plot with ammoniaeal salts only, the lowest per cent, in the grain ; and with . the medium relation in the other plots, the medium per cent, in the produce. Excepting, however, abnormal conditions, as already remarked, variation in climatic circumstances, has much greater influence on the percentage-composition of wheat-grain, than variation in manuring. Let us now turn to the composition of the ash of wheat-grain. Independently of the defect of a sufiicient number of published analyses of wheat-grain ash, a dozen years ago, when we took up the subject, it was then generally believed that the composition of the ash of vegetable produce, would vary considerably with the supplies of the different constituents in the soilj it was thought indeed, that according to the abundance of their presence, one base might substitute another, as for instance soda, potash, and so on. About the same time that we undertook a series of wheat-ash analyses, the ashes of various succulent vegetables were also analysed. This latter investigation led us to conclude, that the fixity of the composition of the ash of such substances, depended very much upon the degree of niatura,tion of the produce ; and in ON THE COMPOSITJON OP WHEAT-GKAIN, &C. 15 fact that ' sojne constituent^'^soda ^od chlorine for ^nstancgTr.,- occurred in much larger quantities in the more succulent aijd unripe, than in the more elaborated specimens. It seemed to he perfectly consistent with thig experience, to find in the jish of a comparatively perfected vegetable product like wheatrgrain, a con- siderable uniformity of composition — such indeed as the analyses no^ to be recorded will indicate. These analyses were made ten years ago by Mr. Dugald Campbell, and the late Mr. Ashford. And as, since that time, the methods of ash-analysis have in some points been improved upon, it will be weU to give an outline of the plan then adopted : especially as it is by a consideration of the tendencies to error on some points, that we must interpret the bearings of the actual figures given. On this point we need only add, that Mr. C a pip- bell fully concurs in the tenor of our remarks. Method of Analysis : — Three portions of ash were taken. No. 1. In this the sand, silica, and charcoal, phosphate of iron, phosphoric acid, lime, and magnesia, were determined, The ash was dissolved in dilute hydroghloric acid, evaporated to perfect dryness, moistened with hydrochloric acid, boiled with water, and the insoluble matter collected and weighed, as — sand, silica, and charcoal. To the filtrate, acetate of ammonia was added, and after digestion, the precipitate separated, dried, ignited and weighed — as phosphate of iron. To the filtrate now obtained,' a solution of a weighed portion of pure iron dissolved in nitro-hydrochloric acid was added, then acetate of ammonia, and the mixture digested until the whole of the iron was precipitated as phosphate of the peroxide with excess of peroxide, from which was calculated the phosphoric acid. From the solution filtered from the phos- phate of iron and oxide of iron, the lime was separated as oxalate and ignited as carbonate; and from this last filtrate, the magnesia, by phosphate of soda and ammonia. No. 2. A second portion of ash was put into a carbonic acid apparatus, the acid, if any, evolved by means of nitf ic acid, and determined by the loss. The solution being filtered, sulphuric acid was separated by nitrate of baryta ; and afterwards chlorine by nitrate of silver. No. 3. To a solution of a weighed portion of the ash in hydrochloric acid, caustic baryta was added in excess, and the precipitate separated by filtration ; the excess of baryta was then 16 lAWES AND GILBERT removed fey carbonate of ammonia, and the filtered solution evaporated to dryness, the residue heated to redness and weighed ; "water added, any insoluble matter deducted, and the remainder taken as chlorides of potassium and sodium ; a solution of chloride of platinum was now added to separate the potash; the soda being calculated from the loss. It is now admitted, that the separation of phosphate of iron from the earthy phosphates by acetate of ammonia as above described, is unsatisfactory ; and it is probable the amounts given in the tables as phosphate of iron are too high, and if so, part of the difference should obviously go to the earthy bases. For a similar reason it is possible that the phosphoric acid determinations may be somewhat too high — also at the expense of the earthy bases. Then again, it is well-known that in practice the process for potash and soda, is one of some delicacy ; and that the tendency of manipulative error is to give the soda somewhat too high. We conclude upon the whole, that our phosphoric acid determinations may be somewhat high ; our phosphate of iron pretty certainly so ; and probably the soda also ; the other bases being, on this supposition, given somewhat too low. The wheat-grain ash-analyses, 23 in number, and referring to the produce of three separate seasons, and of very various manur- ing, are given in the following Tables — numbered IV, V and VI respectively. ON THE COMPOSITION OP WHEAT-GEAIN, &C. 17 Pi • •3 Tp > 1— 1 S Tt< C5 1 CO H t? 1- < (U En 05 H Cm -. -13 a ^ 1^ US w CO■THMl^-^-OCOlO iO § cq i-l S S s CO (M m i-c OCqoOCqi-lCO ^y-\ -^ G^i r-t j^ OS ^1- ■^ CO CO OS llll"« CO C0'*C0O00iHr-[.b* b- 00 WS CO o> ■^jiioppcococq'* p CO -^-^ 23 i-t sitii CO CM CO cq iH cq CO i-H CO r^ CO ■^ CO 00 »o cq 1-t OS ««1M^ 1 Jl UtJ -i Superpho pliate Lim Potash an Magnesia and Silical Totasli. (M Os0030CO.b-OSCO CO f-i p o w p CO (M CO cq COOOppr-lOOO O CO OS O CO iH 00 /«*i CD CO lo cq i-H OS S" - ■ft COWSlOOCOCOrHrH o B .s p O5io-*ocoi:^i-icq CO H i' •r=« o> cq OS o CO ' cq oo a> ' fi is ««0 „U3 n cooq p P ^ cq iH OS OO (M CO Cq S^S". m ■* CO CO cqcqcoO'*Oi»o^- lO 1 1 OS cq OS o CO cq OS ^ -«*i cq rH OS i a u" .§ s „-s »• CO oooocqoi-iGqvo 00 iH -^ p CO p "^T'T^T'T''^*?'?* CO S uo «o CO OS cq j-H o cq i>i-t o cq JO OS ll°F >* l£5 QO lo cq I-) OS III lO cqcqj>-cqrHco oqos tH lO )-i cq rH oq OpCOtNprH g-* J^- u u o CO CO rH Cq iH cq OS 1-1 CO S )H W5 cq iH ^ os tl° •TtMO CO OS t^ -*iocqo-«^ocqcq OS C^ rd cq »o 00 iH co^cqoooi-(X^' 00 CO § i vo CO i-H cq o cq o iH CO cq o ■^.lOOO lO CO rH o r-i lii (O COCOjHCOM<1^- eq^ I-H M ■tH « CO O rHlOpI>COi>. gCO CO cq CO I-H CO g cq -«*i cq I-l ^ CO CO OS cq cq oo ■tH lO CO Oi ^ _,i- ^ .-T^ ^ • • .— s. * . • /— nO • ^Cq cj-g C '— ' '' fc_ Produce essed Co in Corn bstance : : ,he produce : — Com in Total er bushel of Dr Dry Substance Ash in Dry Su :::::: :| : ; v tituents of Ash : — Phosphoric Acid Phosphate of Iron Potass Soda Magnesia . . Chlorine Silica^ Sand, and Gl o EH "i irs of i Cent. Cent. Cent. !^ 1 ■g « ^ 3 S P^ 1 O O LAWES AND GILBERT pq CO o 00 CO t* i-( - cq »a Oi Oi ^ ir- O i-H (NO(MOO0Q OCT O iH (M O C0f>1 CM vo CO i-H tri oi CO O 00 OS M-S Superphos- phate Lime 112 lbs. Sulphate Ammonia 112 lbs. Kape Cake 660 lbs. * (M OS •= 1 s CO OSi-ICOOCOt-OOS i^ OS 1> WS (N OS C000WO»0»0(NC0 (M -* CO rH tH 00 CM CO iH CO CO 00 CO Wi CO ^ CM rH OS & ■2 - s. £ i OS eOb-COi-HCDCDOOS CO T" a -a ■*tf J> O OO OOii-IOOCOOCq cq IM II-- CO CO O tH 1> r-t W5 00 I-H CO CO o CO W5 CO -* CN i-H o I-H ai o eo c^o CO -^ ** o S* to CO CO rH 03 00-*t-r-lJ!-OOrH-* *q g CO CO ^ 1H oa cq oa o CO C4 OS 8 ■* «D 00 ■^ cq iH OS J' .'4 .s«.«"il I-* OD«0000"*Cqt^O lO n S,a 6^ V (U gC4 IH A CO qa ^«socp-**C080-*'* T-i M fS jH ifa ip V>£i 0» ^W3WO»-H«>C0»0 OJ 00 skills CO CO ^ I— 1 0> (M OS rH -^ (N o ^ !0 00 -* oq rH O' ■ rH CO 1 Mf (MOCOOOi^OOO sa tH 1 s to CO CO ^ TOrHOSOJ^-OCOrH OS i i CO (M CO CT o CO i> o '^ cq qo •«*t <0 00 »0 (M rH OS p, - •d * 1 ' CO caeooU3^csosl>- P- CO -* 1^- o o oOtocOCqosoOOrH s -* CO TH -* CO rH OS |3 ij ... . 1 - t^ rH>fflco>oeoS>N GILBERT It is at once seen, that this ash may be reckoned to contain neither sulphuric acid, carbonic acid, nor chlorine. The latter at least occurred only occasionally, and then in such small quantities, as to lead us to the supposition that its presence is accidental, or at any rate not essential, in the ash of a perfectly-ripened grain. From the frequent absence of soda again, and from the uncertainty in its determinations as above alluded to, we are led to look at it as an equally unessential ingredient in the grain-ash of perfectly ripened wheat. Excluding then the chlorine, the soda, the iron of the phosphate of iron, and that portion of the matter collected as insoluble, which may have been soluble silica — ^the whole of these, on the average, amounting to a very few per cent. — the ash of wheat-grain is seen to consist essentially of phosphates only ; the bases being potash, magnesia, and lime. The potash amounts to nearly one-third of the whole ash ; the magnesia to rather more than one-third of the potash ; and the lime to about one-third of the magnesia. If we now compare with one another the analyses of the eight different ashes in 1844, those of the seven in 1845, or of the six in 1846, having regard to the manures by which the crops were grown, it is impossible to say that these have had any direct and well-defined influence upon the composition of the ash of the grain. Thus we find, looking at the Table for 1844, that several of the plots manured with superphosphate of lime, yield a grain-ash having no higher percentage of phosphoric acid than that of the unmanured plot. Again, where potash is added (plots 15, 16, and 18), the percentage of it in the ash is not greater than the average of the cases where it was not employed. And again, in the only case where soda was employed (plot 16), there is none of it found in the ash ; nor, lastly, is the percentage of magnesia obviously increased by the use : of it in manure. A similar detailed consi- deration of the composition of the ashes of the seasons of 1845 and 1846, would, as already intimated, lead to a similar conclusion. In fact, the variations in the composition of the ash of this supposed ripened product, according to the manure by which it is grown, seem to be scarcely beyond the limits of error in the manipulation of the analysis ; though, one case at least of the duplicate analysis of the same ash — namely, that of No. 9, 1844 — indicates the range of variation from this cause to have been but small ; in the other, (No. 17, 1845) it was somewhat greater. Although the accuracy of the analyses may not be such as to ON THE COMPOSITION OF WHEAT-GKAIN, &C. 21 show the difference in composition, if any, dependent on manure, yet it is fotind to be quite adequate to indicate the marked diffe- rences in the degree of development and maturation of the grains, dependent upon season. Before calling attention to the figures illustrating this point, it should he remarked that the season of 1845 was the worst but one, and that of 1846 nearly the best, for ripening the grain, during the thirteen years of our continuous growth of wheat. And we shall find, consistently with this, and with the conclusions arrived at in connection with Tables I and III, that the variation in the composition of the ash is, comparing one year with another, much the greatest in the produce of the bad ripening season 1845, and much the least in the good ripening season 1846. This point, and some others, are illustrated in the following Summary Table, No. VII. 22 LAWES AND GILBEET PP g o a o i 1 1 si* OS rH Cd ^ W CO(?!| -* (I^ Wjr ooo-*i^co»r3cooiHeo lO O W * CM i-H us CM OS OS CO o ^ CO CO O 00 CD -^ CO J^- 1:- O CO lO tH >rs OS »0 O CO . . rH 'til O * CO coasQOi-(i>-o , , . . CO CO "^ s^s p^ d.: 6 "5 S 6 l1 .1 •E.S 39 V^ ■a S) a £"^ .3 .3 p,(^^(l^fl^cQ;^^aJOOm ON THE COMPOSITION OF WHEAT-GEAIN, &C. • 23 Looking at the first Division of this Table VII, it is seen that in the item of phosphoric acid, the variation in the percentage among the several cases in each year, is the greatest in 1845, and the least in 1846 ; in the phosphate of iron, it is the greatest in '1845; in the potash, it is the greatest in 1845, much less and about equal, in , 1844 and 1846 ; in the soda, it is much the greatest in 1845, and much the least in 1846; in the magnesia, it is again far the greatest in 1845, and it is the least in 1846. In the case of the lime, we have an exception to this general indica- tion, dependent on the two low amounts of it given for Nos. 3 and 3, 1846; but if these are really in error in the direction suggested at the foot of Table VI, the indication would be the same as for the other constituents. We have then in the circum- stances of the seasons, and in the comparative characters of the produce coincident with these variations, the evidence that for one and the same description of grain, in a perfectly matured condition, the composition of the ash vnll be, within certain narrow limits, constant. So far as the constituents of the ash of the entire grain of wheat is concerned, we have only further to call attention to the three other Divisions of this Summary Table No. VII. In these are shown, side by side : — In the second Division of the Table, the mean composition of the ashes for each of the three separate years ; In the third Division, the mean composition for the three years together : (a) of the grain-ash from the unmanured plot — (6) of that from the farm-yard manured-plot — (c) of the grain-ashes from aU the other manures during the three years, including 17 cases; and In the fourth and last Division, the mean composition of all our own wheat grain-ashes analyzed, 23 in number, by the side of the mean of 26 analyses of the grain- ashes of wheat, of different descriptions or grown in different localities, published by Mr. Way. We wiU go into very little detail discussions of these mean results, as the points they illustrate have most of them already been alluded to. We may first remark, as a point to which we shall recur further on, that the mean percentage of lime, is the least in the bad year 1845, and the greatest in the good year 1846. Again, it is greater in the average from the manured plots, than in that from the unmanured. We may perhaps here anticipate by saying, that this is at any rate consistent with what we shall 24 LAWBS AND GILBERT afterwards have to record, namely, that the ash of the finer flour — of which there is a greater proportion in the grpin of the seasons of best maturation — contains more lime than that of the coarser and more branny portions of the grain. Lastly, in reference to this Summary Table, we would call attention to the mean composition of wheat grain-ash yielded by the 26 analyses given by Mr. "Way, by the side of that of the 23 specimens grown at Rothamsted. Mr. Way^s analyses, equally with our own, show that wheat grain-ash essentially consists of phosphates of potash, magnesia, and lime. He, however, if we exclude sUica, gives higher percentages of base, and a lower one of acid, than our own analyses indicate. Mr. Way's average amount of phosphoric acid is indeed nearly 5 per cent, less in the ash than ours. His series, however, included many descriptions of wheat, and our own only one — the Old Red Lammas. In several of his cases, too, we observe that the percentage of this acid very closely approximates to our own average. "We have now given a summary view of some points of the composition of the entire wheat-grain, and of its ash, as affected by varying season, and various manuring. "We next turn to an equally summary statement, of a large number of experiments made in reference to the yield, and composition, of the various products separated in the milling process. The grains operated upon vnth this view, were of the same description of wheat, but grown experimentally in different seasons, and under different conditions of manuring. There have been many observations recorded as to the percent- age of flour obtained in practice from 100 parts of grain, and in a subsequent Table some of these will be adduced. We are also indebted to M. Boussingault for the determination of the flour and of the bran, yielded by 24 different descriptions of wheat, all grown side by side in the Jardin des Plantes at Paris. His method was to powder the grains in a mortar, and separate the flour and bran by means^ of a silken sieve. Results of this kind can, perhaps, scarcely be compared with those of the ordinary mill. The differences exhibited between the different specimens were indeed very great ; but the comparisons afforded within the series itself are interesting and very curious. In our own experiments, the so-called Colonist's steel hand-mill was first had recourse to j as it was thought that by its use, rather ON THE COMPOSITION OF WHEAT-GEAIN, &C. 25 than that of an ordinary flour-millj much smaller quantities of grain might be submitted ,to experiment, and that uniformity of working would also be more within our control. It was soon found, however, that in all cases the grain was, in this steel-mill, rather cut up than crushed and rubbed down, as between ordinary mill-stones. It was also found, that the action in this respect varied considerably according to the speed of the operator, and to the precise set of the mill, which required to be varied according to the character of the grain. Prom these causes a statement of the amount of the yield, of the various products obtained from the steel hand-mill, would be of little value. Though further on we shall have to call attention to some interesting points connected with the comparative composition of the several products of the grains mechanically separated in this way. We next determined to submit a series of the experimentally grown grains, to careful, and as far as possible, uniform treatment between the stones, and in the dressing apparatus, of an ordinary flour-mill. The mill in question was worked by water-power. From 125 to 250 lbs. of the several grains were submitted to the experiment ; the whole of the apparatus being carefully cleared of the products of one specimen before another was commenced upon. The weights and samples of the "meals" as furnished by the stones, and of the several products separated in the dressing- machine, were taken under our own personal superintendence. Even here, and although every possible precaution was taken, considerable irregularities in the action of the apparatus were manifest, depending partly on the varying characters of the grain. Indeed it was clear, that to obtain results as to comparative yield of flour, strictly referable to the practical qualities of the respective grains, it would be necessary to operate on much larger quantities of each than those even now taken, in order that the miller might so re-adjust the set of his stones, as the work proceeded, according to the character of the grain and of the meal which it afforded, as to get from each its largest yield, as he would do in working upon considerable quantities. In all, twenty-eight lots of grain were operated upon in this way ; and although, as above implied, and as will be pointed out further on, the results might in some points have been somewhat different with larger quantities, yet the miller, after a careful examination of all the products, decided that their general bearings were to be fully trusted. In some cases the meal obtained from the stones was separated 26 I,AWES AND GILBERT in the dressing apparatus into nine products, and in others the products of the first three wires were taken togethef, constituting the bulk of the fine flour obtainable, and amounting to only about 70 per cent, of the grain. In practice, however, the fourth product of the dressing machine, " Tails" is generally redressed, and the fifth, "Fine Sharps" or "Middlings" reground and redressed, together raising the amount of good bread-flour to about 80 per cent., or sometimes more. The sixth product is called " Coarse Sharps;" the seventh, " Fine Pollard ;" the eighth, " Coarse Pollard;" and the ninth, "Long Bran." It should be stated, however, that mills vary very much in the arrangement of their dressing machines in different localities, and even in the same locality; so that the exact division of the products here given, will not apply invariably. In Table VIII are given — 1st. In the upper division of the Table, the percentage yield in 100 meal, of each of the mill products, 7 or 9, as the case may be; each figure being the mean of several experiments. 2nd. (In the middle division of the Table) — The mean per cent, of dry substance (at 213°), in each flour, bran, &c. And, 3rd. The mean per cent, of mineral matter (ash), in each of the same mill products. As wiU be seen, seven of the specimens were grown in 1846, nineteen in 1847, and two in 1848 ; and in order to give some idea of the general character of the produce yielding the results in each of the separate columns, there is given at the head the mean bushels per acre, the mean weight per bushel, and the mean per cent, of corn in total produce, of the specimens to which the column refers. ON THE COMPOSITION OP 'WHEAT^GRAIN, &C. 27 TABLE Tin, Showing the yield of the different Mill Products from 100 of Grain ; and their Per-oentages of Dry Suhstance and Mineral Matter. Meas Eesults. Products of Wires 1, 2, and 3. II Means of aU in each year. 2 3" 18i6 1847 1848 1846, 1847, 1848, ■3.g >f ij t^ H * If .f^ S S 7 19 2 ■S"" Ill II |8> "i ^ It II' cases. cases. cases. &s Ss & ^ w5 H & Mean Mean Mean Mean Mean of .S of* of 4 of 15 of 2 General Characters of Proflnce :— cases. cases. cases. cases. cases. Mean bushels per acre 26i Hii an S3 m 38 31 + 31+ 30i Mean weight per bushel fibs.).., 68-5 63-3 61-7 63-2 59-1 63-4 63-1 69 -1 63-3 Mean p. c. com in total produce. 43-5 4S-7 35 '9 38-0 87-1 43-0 36 1) 87-1 37 -8 Yield of Flour, Bran, &g., in 100 Meal. 1. Wirel 3. Wire 2 S. Wire 3 ... 44 17-9 8-7 86-7 16-4 13 -3 47-4 23 -9 2-0 44 17-9 87 36 7 16-4 13 3 47 '4 23-9 3'0 41-1 18-6 9-3 Products 1, 2, and 8, together. 4. TaUa 6. lUne Sharps or Middhnga 70-6 4-6 8-7 68-3 6 1 11-4 65-4 7-7 10-3 71-5 6-3 8'3 73 8 3-1 4-6 69-3 4-9 10-3 70 '2 6-8 8-7 73 -3 2-1 4-5 70-3 9-3 8-8 6. Coarse Sharps 7. FinePoUard 8. Coarse Pollard 9. Long Bran 3-1 1-8 6-6 4-3 3-8 6-5 2-7 . 2-9 3-6 1-9 7-4 3-3 8-3 1 8 7-1 3-3 3-6 3'6 7-9 S'9 3-5 3-9 4-4 3-6 3-8 1-8 7-3 3-6 8-6 2-B 7-9 6'9 3-4 .B-4 6-5 3-Q Per Cent. Dry Substance (at 212° P.) in each Plour, Bran, &c. 1. Wire 1 2. Wire 2 3. Wire 8 84-4 84-5 84-5 ... 88-8 83-7 83 9 86-4 85 2 86 '3 84-4 84-6 84-6 88-8 83 7 88-9 86-4 85-3 85-2 84-3 84-3 84-4 Products 1, 2, and 3 together. 4. Tails _ ... 5. Pine Sharps or Middlings 84-4 83-1 84-7 86-3 84-9 84 3 84-0 83-8 86-2 84-7 85. S 85-3 84-6 84'8 84 a 83 8 86-0 84-6 85 '3 86 -6 86-3 84-1 85-0 84-5 6. Coarse Sharps 7. line Pollard 8. Coarse Pollard ... 9. Long Bran 86-6 87-3 86-4 86-3 85-1 85-8 81-9 85-6 82-3 83 -a 83-6 83-1 86-3 85-5 86-0 85 6 85-4 8S-7 86-2 83-7 85-7 86-4 85 '5 85 '8 86-3 84-8 85-3 85-1 85-4 86-7 86-2 85-7 85 -4 86 -3 85-4 86-3 Per Cent. Mineral Matter (Afih) in each Flour, Bran, Sec. 1. Wire 1 i.i 2. Wire 3 3. Wires ... iii 0-70 0-71 0-75 ... 0-68 071 0-74 ..i ' 0-70 0-73 0-87 0-70 0-71 0-76 0-68 0-71 0-74 0-70 0-73 0-87 0-69 0-71 0-73, •384 ■133 •067 Products 1, 2, and S, together. 4. Tails ... ..i 5. Pine Sharps cr Middlings 0-93 1-83 0'71 1-01 V88 0-93 1-64 0-70 108 3-48 104 1-88 0-71 0-9? 1'85 0-70 1-06 3-34 0-77 1 04 1-88 0'71 103 2-13 ■483 •054 •186 6. Coarse Sharps 7. Pine Pollard 8. Coarse Pollard 9. Long Bran ... ... t.. Total 3-77 5-86 6-91 7-68 4-35 6-01 6-86 7-37 3-74 6-45 6-41 6-67 4-43 6-65 6 89 7-19 3-64 5 '03 6-84 6-34 4-10 6-94 6-88 7-42 4-38 5-61 6-39 7-08 3 54 6 08 ■6-84 6-34 4-18 5 65 6 47 7 11 •143 •136 ■430 •S13 1-634 28 LAWES AND GILBEET After the remarks already made, little need be said in detail regarding the comparative yield of the various products by 100 parts of the diflferent meals. It was decided by the miller, that pretty uniformly there was too much flour left in the fourth, but particularly in the fifth product ; and this, as an inspection of the Table will show, was obviated in the later experiments, namely, • those on the grain of the harvest 1848. So far, then, the variation of the result is more due to the management of the miUer, than to the intrinsic character of the grain. It is more interesting to observe, that a very careful examination of all the products led to the conclusion, that the grains grown by the more nitrogenous manuring, and consequently in the larger cro^s, provided they were well developed and matured *a]lowe&a,hetter separation of the flour, and less cuttingup and intermixture of branny particles with it ; and hence, yielded a cleaner bran than the grain of the poorer crops. This was not the case, however, unless the highly-manured crops were at the same time well developed. It is consistent with this character of the grain of the more highly- manured crops, that the produce of the heavier and richer wheat- lands is generally admitted to yield a larger proportion of flour.. The fact that the graia of richly-manured crops is frequently coarse, and not the good miller's sample, arises from, the circum- stance, not of the direct effect of rich manuring in depreciating the quality of the grain, but because the larger crops are more subject to injury due to climatic circumstances, and are conse- quently frequently less favourably developed and matured. It will be observed, that the amount of long bran is always more than 3j and in the year of badly-ripened grain (1848), it is nearly 6 per cent, of the total meal. This ninth product, together with the three or four immediately before it in the list, yield us nearly 20 per cent, of the total meal, of such a branny character as seldom to be used for human food. Some of the more recent expe- rimenters, MM. Millon and Peligot for example, have concluded that the amount of actual woody fibre in wheat-grain is seldom more than from 3 to 3 per cent. On this supposition, the nearly 20 per cent, of the grain generally not applied directly as human food would contain but a small proportion of necessarily indigestible woody matter; and it would appear that there was very great room for improvement in the modes of preparation of the grain, if * It would appear that, in a good ripening season, this condition is best attained •R-hen the crop is cut before the grain is perfectly ripe. ON THE COMPOSITION OF WHEAT-GRAIN, &C. 29 it were desirable to separate as human food in the first instance, a larger proportion of its nutritious matters. M. Poggiale, on the other hand, maintains that the quantity of woody fibre refractory to the digestive organs, though not to chemical agents out of the body, is really very considerable.* But, of some points of the composition of the various products, we shall have to speak more in detail presently. In the second or middle division of Table VIII, we have the average percentage of dry matter in the different products. In reference to these results it may be noticed, that, as might be expected, the percentage of dry matter is rather higher in the mill products, than it was in the entire grains which yielded them. This is particularly the case in regard to the two specimens of the harvest 1848, the mill products of which give, on the average, a higher per cent, of dry matter than the samples of either of the other two years, although the dry matter of the entire grain of that season (1848), was very low. The differences are therefore obviously more due to the circumstances of preservation and after- treatment, than to distinctions in the character of the respective grains. The only other remark which need be made regarding the varying percentages of dry matter, is, that the branny, or more external portions of the grain, have pretty uniformly a higher percentage of dry matter than the more farinal internal portions. The widely differing percentages of mineral matter in the several mill-products of the same grain, and the variations in this respect, even between the corresponding products in the different speci- mens, in the same, or in different seasons, are both more striking, and of greater interest. It is seen, that we have about ten times as high a percentage of ash in the ninth product, or bran, as in the first three, or purer flours. The percentage increases rapidly from the fourth to the ninth — that is to say, the greater the proportion of branny par- ticles. A careful examination of the more detailed Tables also showed, that the variations in the percentage of mineral matter in the corresponding products of different specimens of grain, had a direct relation to the percentage, or relative position of the respective products, in the 100 of meal; in other words, to the * Since the above was written, a very favourable report has appeared in the " Comptes Eendua " (January 12, 1857), by MM. Dumas, Pelouze, Payen, Peligot, and Chevreul — the Commission appointed by the Academy of Sciences, to inquire into the matter . — on a new process of M. Mfege Mourifes, which claims to yield a perfectly, white, wholesome, and agreeable broad, employing 86—88 per cent, of the entire grain. 39 LAWES AND GILBERT proportions of flour or of bran whieh tliey respectively contained. Although, however, the percentage of mineral matter is so very much greater in those portions of the grain which are not gene- rally used in the first instance as human food, yet, an inspection of the last column of the Table, showing the distribution of the mineral matter in the several products of 100 of meal, according to the amount of each of these, will show that, even in our first three products, we have nearly one-third of the whole mineral m'atter of the grain ; and adding to these a certain portion of that in the fourth and fifth products, which frequently contribute to the bread-flour, we shall have more than one-third of it in the currently edible portion of the grain. Further information as to the composition of the respective mill-products, and of their ashes, will be found in Tables IX, X, XI, and XII. In Table IX are given the individual nitrogen determinations in each of the several miU-products ; those in the first three columns being by one experimenter, and those in the fourth column by another. In Table X is given a collective view of the composition of the same products, in regard to some other consti- tuents, as far as they have been determined ; including also the mean results of Table IX. TABLE IX. Determinations of Nitrogen per Cent, in Mill Products of Wheat-Grain. Harvest 1846; ground 1848. In natural state of dryness. Description of Mill Products. Experiments. Mean. \. 2. 3. 4. :. Wirel 2. „ 2 3. „ 3 1-59 1-64 1-77 1-69 1-73 1-78 1-62 1-69 1-79 •• 1-63 1-69 1-78 4. TaUa 5. Fine Sharps, or Middlings 1-88 2-20 1-86 2-20 1-84 2-22 2'-22 1-86 2-21 6. Coarse Sharps 7. Pine Pollard 8. Coarse Pollard 9. Long Bran . . 2-58 2-43 2-41 2-37 2-52 3 37 2 32 2-37* 2-59 2-48 2-47 2-62 2-48 2 '46 2-42 2-58 2-44 2-42 2-39 By a third experimenter. ON THE COMPOSITJOiT OF AVHEAT-GRAIN, &C. 31 ri ^ O +a cd o Qt) tH ^ ou tw n O '^ . m fc> X o o w 'T3 CB ^ CD ■< S OO H .'T? I-H ^ =*H N o l> S o M o p< s o CJ 1 u i . rH cot* ■ OS t- ■* rH (M W5 o !0 OO O O CO (O lO'*** Oi iO »H O O ■? 9 O O M rH 00 s 1 03 J3 o o o o o O O O O o fi S o . ' ^ 33 (MOO O !M WS rH - 1 .a J 00 rH O O O O rH rH ^ CO O O O O 1-t o '5 j3 ^ 3 CO WS i-l ■?" '!' «0 CO * »o iOlO ,d ^ 03. PL, O O -* CO '^ 00 -"^ -isH -* CO O O 00 ir- rH 3 OO OO »tt «o ; KH VOiOVi tN CO CO O O O • iH CO OS 00 to tH 00-* w o p eo CO ooi>. o ^ \ r-i -^i-l I-H « CO rH CO K5 Oi W5 CT 03 & j_j : : : •s • : : : : \ ■11 i-( (N CO I¥j o 1;: i.aig" EH ^ I-H cq eo -* lO CO r-^ 00 o^ 32 LAWES AND GILBERT The grain to which Tables IX and X refer, was an equal mixture of the produce from four different plots, very variously manured, and grown in the season 1845-6; the harvest of which yielded one of the best-matured grains throughout our series of field experi- ments. The wheat in question was, however, not ground until 1848 ; and we have in the percentage-yield of the respective pro- ducts, confirmation of the general opinion, that other things being equal, old wheat yields up its flour better than new. ,Thus, whilst in the average of the cases already recorded, we have little more than 70 per cent, of flour through the first three wires, we have from this old wheat 77| per cent. The products 4 and 5, from which a further yield of bread-flour is obtained, were correspondingly small; but Nos. 8 and 9 were, on the other^hand, somewhat large. The particulars given in Table X are the percentages of Dry Matter, of Ash, and of Nitrogen, in the respective miU-products of this mixed grain. There are also given the percentages of Matter insoluble in Acid, and oi phosphoric acid in each of the nine ashes; and in the last four columns we have the distribution of the total mineral matter, of the nitrogen, and also of the insoluble matter, and phosphoric acid of the ash, in each of the nine products, according to the proportion of the latter in 100 of the grain or meal. The percentage of Dry Matter in the several products from this old grain is, as would be expected, somewhat higher than the average from the grains of the same year which had not been so long stored. As before, the percentage of Dry Matter shows a tendency to increase as we proceed to the outer portions of the grain. The percentages of ash also show the same relations as already pointed out. Referring to the column of the percentage of nitrogen in each of the nine separated products, we find that it is lowest in the products at the head of the dressing machine — that is, in the flours ; and it is half as high again in the more branny portions. It is seen, however, to be the highest of all in the product No. 6 ; and somewhat lower in the coarser brans. It may be remarked that the indications of the figures in this respect are at any rate consistent with such observations as have been recorded regarding the structural composition of wheat-grain; it being stated that the greatest concentration of nitrogenous compounds is imme- diately below the pericarp itself; and we should expect that the ON THE COMPOSITION OF WUEAT-GKAIN, &c. 33 longer bran would have less of the more internal matters adherent to it. The higher percentage of nitrogen in bran than in fine flour, has frequently led to the recommendation of the coarser breads as more nutritious than the finer. We have already seen that the more branny portions of the grain, also contain a much larger percentage of mineral matter. And further, it is in the. bran that thelargestproportion of fatty matter — the non-nitrogenous substance of highest respiratory capacity which the wheat contains — is found. It is, however, we think, very questionable whether, upon such data alone, a valid opinion can be formed of the comparative values as food, of bread made from the finer or coarser flours from one and the same grain. The published evidence at command leads to the conclusion, that of the nitrogenous constituents of bran, a much larger proportion is soluble in water, than of those in the finer flours. That is to say, there is in the bran, probably, a larger proportion of the more universal vegetable compound, albumen, and less of those more special to the grain of wheat; and hence we may perhaps conclude, that it exists in a less elaborated, and probably, therefore, less assimilable condition.* It is stated, on the other hand, by Poggiale, that a large proportion of the insoluble nitrogenous constituents of bran, occurs in a form only in an inferior degree digestible. Again, it is an indisputable fact, that branny particles, when admitted into the flour in the degree of imperfect division in which our ordinary milling processes leave them, very considerably increase the peristaltic action ; and hence the alimentary canal is cleared much more rapidly of its contents. It is also well known, that the poorer classes almost invariably prefer the whiter bread ; and among some of them who work the hardest, and who consequently would soonest appreciate a difife- rence in nutritive quality (navvies for example), it is distinctly stated, that their preference for the whiter bread is founded on the fact, that the browner passes through them too rapidly ; con- sequently, before their systems have extracted from it as much nutritious matter as it ought to yield them. * According to M. Mfege MouriSs, before referred to, a portion of the soluble nitrogenous matter of bran exists as a peculiar body, Cerealine, which when dissolved up from bran in water at a given temperature, effects the solution of the adherent starch also. His process of extracting from the bran an additional amount of the bread-material which the grain contains, consists in fermenting, after the addition of some glucose, an infusion of the finer brans, straining off the woody matter, and using the fluid in making up the dough with the finer flour. D 34 LAWES AND GILBERT . It is freely granted, that mucli useful nutritious matter is, in the first instance, lost as human food, in the ahandonment of 15 to 30 per cent, of our wheat-grain to the lower animals. It should be remembered, however, that the amount of food so applied, is by no means entirely wasted. And further, we think it more than doubtful, even admitting that an increased propor- tion of mineral and nitrogenous constituents would be an advan- tage, whether, unless the branny particles could be either excluded, or so reduced as to prevent the clearing action above alluded to, more nutriment would not be lost to the system by this action, than would be gained by the introduction into the body coinci- dentally with it, of a larger actual amount of supposed nutritious matters. In fact, all experience tends to show, that the state, as well as the chemical composition of our food, must be consi- dered; in other words, that its digestibility, and aptitude for assimilation, are not less important qualities, than its ultimate composition. Observation also tends to show, that elaboratioQ, or maturation, have their influence in determining the digestibility or the assimUability of our food — both the vegetable and animal. But to this point we shall refer again presently. Returning to the experimental results in Table X, the next point of remark is as to the amount of matter insoluble in acid, in the ash of the respective mill-products. It is seen, that the percentage of such matter is very much greater — indeed in this particular case, ten times greater — in the ash of the finest flour, than in that of the coarsest bran. It was. at first thought that this must be an error. Some repetitions were therefore made, and the products of the steel-hand-mill were also examined ; when it was found that the result in question was fully confirmed. It would be interesting to examine the series, to determine what proportion of this insoluble matter is really proper mineral consti- tuent of the respective products, and how much adven,titious merely. On consideration, it wiU however be clear, that the process of dressing the meal would tend to shake and clean the bran, from all adherent matters ; which, if silicious, as well as the particles arising from the abrasion of the mill-stones, would natu- rally be found among the heavier products at the head of the machine. That is to say, they would be found in larger propor- tion in the flour, whilst the bran, by the mechanical methods of its separation, would be almost entirely freed from them. Accord- ing to published analyses, it would appear, however, that silica^ aa ON THE COMPOSITION OF WHEAX-GEAIN, &C. 35 distinguished from merely insoluble sandy matter, does exist to a considerable, though variable extent, in the ash of entire wheat- grain. And from the results now given, it may perhaps be concluded, that this constituent found to exist so constantly in some animal substances, does really occur in larger amount in those portions of wheat-grain which are best adapted as food ? Phosphoric acid, on the other hand, is seen to be in smallest proportion in the ash of the flour at the head of the dressing machine; and the percentage pretty gradually augments as we proceed from the finer to the coarser and more branny portions, the ash of the latter being far the richest in this essential acid.* It may further be remarked in reference to the varying compo- sition of the ash of the different mill-products, that in several series we have found the magnesia greatly to increase as we pro- ceed from that of the finer to that of the coarser products. The percentage of lime is, on the other hand, greatest in the ash of the flours, and less in that of the brans. This latter point is consistent with a tendency discernible, to an increase in the percentage of lime in the ash of those grains most matured in one and the same season, or in the ash of the grains grown in a season of higher maturing character. We may further conclude, from the great increase in the percentages both of the phosphoric acid, and of the magnesia, as we proceed from the ash of the flours to that of the brans, and also from the very slight compensation from the decrease in that of the lime (the total amount of Ume being relatively small), that the chief complementary constituent of wheat-grain ash — namely, potash — will occur in larger proportion in the ash of the flours than in that of the brans ; hence, its larger amount will be coincident with the larger amount of silica. In the last Division of Table X is shown the distribution in the respective products from 100 of grain, or its meal — of the nitrogen, of the total mineral matter, and of the insoluble substance and phosphoric acid of the latter — which the entire grain contained. It will be seen, that notwithstanding the percentage of nitrogen is so much greater in the branny products, yet owing to the smaller amount of these, by far the larger proportion of the total nitrogen of the grain is accumulated in the flours. In fact, in the case * Probably a portion of the phosphoric acid existing in wheatgrain-ash is due to the oxidation, during incineration, of phosphorus, found by Professor Voelcker to exist in such large amount, associated with the nitrogenous bodies. See also Professor B- Kose 09 this subject— Poggendorff's Annalen, vol. Ixxvi. p. 305. " ' D 2 36 LAWES AND GILBERT before us about three-fourths of the nitrogen would be accumu- lated in those of the products which would be ordinarily used for bread, or for human food in other forms. On the other hand, only about two-fifths of the total mineral matter would be found with this three-fourths of the nitrogen. Of the phosphoric add again, the larger amount is distributed in the branny portions; only about one-third of it being obtained in the bread flours. At the foot of these columns of the distribution of the constituents, the percentage in the entire grain or meal of the items as determined by analysis in each separate product, is given by the addition of these items so obtained ; and the percentage so calculated agrees very closely with that which the analysis of the entire wheat-grain or its ash would indicate. Thus we may mention, that according to the sum of the phosphoric acid distributed in the different products, we have 50*7 per cent, of it in the ash of 100 of grain or meal ; whilst the average percentage obtained in the analyses of the six ashes of the produce of the same season, was 49*8, an approxima- tion sufficiently near to give some confidence, at least in the relative accuracy of the numerous analytical results involved in such an estimate. Before leaving the question of the comparative chemical compo- sition of the different products obtained by means of mechanical separation from wheat-grain, attention may be called to some results of this kind, in connection Jwith the products of the Colonial steel-hand-mill, which was first employed in these experiments. As will be seen, the results now to be recorded agree in general tendency with those abeady given; yet they have some special and curious points of interest. The individual nitrogen determinations are given in Table XI, and the collected results of the examination of the various products in Table XII. ox THE COMPOSITION OF WHEAT-GBAIJT, &C, 37 TABLE XI. Nitrogen per Cent, in the Products of Wheat-Grain, from the Colonial Steel-hand-mill. (In natural State of Dryness.) Wheat-Grain, Harvest 1846. TJnmanured. Manured. Products from Experiments. Mean. Experiments. Mean. 1., 2. 1. 2. First Grinding : — Wirel .. Wire 2 .. 1-94 1-57 1>89 1-59 1-91 1'58 1-69 1-44 1-60 1-49 l,-59 1-47 Second Grinding : — Wirel .. Wire 2 . . Wire 3 . . 1-89 1-73 1-78 1-90 1-78 1-76 1-89 1'76 1-77 1-60 1-53 1'68 1-61 1-65 1-49 . 1-60 1-59 1-54 Bran 2-07 2 09 2-08 1-69 1'79 1-74 38 LAWES AND GILBERT a I o "o (-1 *« o o O ■s o o 1-H a "O lO 00 «■* r-l o _d ^^ <>l (N O t- ■s| o o i^rH (N la a- l. 03 £« OOS^ la 10Tj« ^lOlO ^ J 2 i r-iW iH iH i-t rH "d Ph ■g g^ £ J M QO 0> ^ 1 oi, cq o o cq »o |- 1 to CO 0> OS 1-1 CO -A "S .s g3 s ■ •So o pq o Fh Cm c^ O • i-i s i "^ a -I a *^ ." m ^ «^ o d o o g^ o O o PI ■$ o m .a 1 Is? ^.° si" ■Si II if sS i2 ^* P4 k m ■A* io'^ 00<»CpW>*«)Cqi-HrH00100t-'©«OW3 OOOO, COCO00CX>00Q0CO00J>'l>-t-t-J>.i:* OOOt^US-^COrHOOli^COirSCOCMrHO So.S £gg "7- ft iOir5COCOi-HrHOOiCOOO«3eO*OUi-«*iCO OOOOCOOOCOOOQO^^i>.l>Jt-A*^l>i>. 15 " ill Hog M(Mi-IOasOOOO£-«31fll>fi'^OOCqr-lrH (Mi-iosoo«m5-*coi-ioa)OO^W'<*-a3»0»O'*iNCqrHi-lO0S0i ooir-i>.J:^l>Jr*t^ir*J>i>JC-ir*l>-i><0<0 C0C0>n-^C0MO0100i>-»0-*C0{Mj-IO 1 1 1 3 S3 1 1 o 1 ■Jl ^s1 COCO^O«DtOJ:^OOOOOS010r-(rH«0e0 Equal to Bread for 100 (r)0-^OOCQ±*iH<»0"iH«)0 1' °5 Oi-lC^«i'*Wi(Ot-COOSOi-l(MCO^U5 a30»aaO)030)oaaoiO>oooooo i-H rH T-H l-H rH t-t 'im .. v^^--^- ■v,-H. -• ^^'^ -«:»•<