THE FARMER'S MAGAZINE. 



381 



exhaustion of previously-accumulated nitrogen in the 

 soil, to direct condensation by the latter of the nitro- 

 genous compounds occurring in the atmosphere, to the 

 formation of ammonia or nitric acid within the soil at 

 the moment of the evolution by chemical changes of 

 certain elements in the nascent state, to the accumula- 

 tion of combined nitrogen from the atmosphere by the 

 plant itself, or to its assimilation of the free nitrogen of 

 the atmosphere — whether, or in what proportion, these 

 several possible sources may take part in the result, is 

 as yet a great problem, open for solution." 



Wiih regard to the important point, of the propor- 

 tion of the nitrogen supplied in the manure, which was 

 recovered in the increase of barley corn and straw ob- 

 tained by its use, the general result, omitting all refer- 

 ence to detail, may be very briefly stated. In the 

 experiments in question, the analyses showed that, even 

 when the nitrogen supplied in manure was the less ex- 

 cessive, scarcely 40 per cent, of it was recovered in the 

 increase of produce, taking the average result of several 

 consecutive years. In some of the individual years, there 

 was nearly, or even over, 50 per cent, recovered — that 

 is, when the tendency to corn was the highest ; in 

 others, there was less than 30 per cent, of the supplied 

 nitrogen recovered in the increase of crop obtained. 



" In thus speaking of the proportion of the supplied 

 nitrogen recovered in the immediate increase of the 

 barley crop, our form of statement must be understood 

 as only representing the practical result, as measured 

 by the difference between the amount of nitrogen in the 

 produce with nitrogenous manures, and in that without 

 them. It must be admitted that we have not the means 

 of deciding whether or not the crop grown by nitro- 

 genous manure has assimilated the same amount of ni- 

 trogen from other sources, as that grown without it. We 

 cannot say, therefore, whether the soil has to render an 

 account of more or less of nitrogen than that indicated 

 by the column of the amounts unrecoveredi:. he increase 

 of crop. The proportion unrecoverod in the imme- 

 diate increase is, however, obviously very large. It may 

 be supposed that this at first unrecovered amount is 

 still available to after-crops. We may as alternatives 



assume, that a portion is locked up in the soil in a piac- 

 tically-unavailable form — that it passes into states of 

 combination in which it can be drained away, or evapo- 

 rated from the soil — or lastly, that in some form or 

 other it is got rid of by the functioual processes of the 

 growing crop. The actual or relative amounts of the 

 several influences, science is not yet able to determine." 



" It is obvious that, at any rate, some of the apparent 

 loss to immediate increase of the supplied nitrogen will 

 be due to the unequal distribution of the manure, in re- 

 lation to the under-ground feeders of the plant. If 

 this were all, however, the unrecovered nitrogen in a first 

 crop should be sooner or later available to those which 

 follow. But one thing is certain, that, even taking 

 together the increase in several immediately succeeding 

 after-years, the proportion then recovered, of the pre- 

 viously unrecovered nitrogen, is very much less than 

 the proportion of the whole supplied, which is recovered, 

 in the year or years of its application. This is even the 

 case when the provision of the necessary mineral con- 

 stituents is very liberal. Indeed, a much less amount 

 of nitrogen newly supplied in the form of salts of am- 

 monia or nitrate of soda alone, will give u greater in- 

 crease of produce than the larger amount of supposed 

 residual nitrogen, with direct mineral manures in ad- 

 dition. It cannot well be supposed, therefore, that the 

 amount of the supplied nitrogen unrecovered is simply 

 due to its greater distribution, or the exhaustion of 

 mineral constituents, though still remaining, so far as 

 state of combination is concerned, available." 



" As a fact in practical agriculture, it must be con- 

 cluded, that the nitrogen supplied in manure for full 

 crops of grain, is not recovered in the increase within 

 any moderate period of time. We hope on an early 

 occasion to add to the statistical results in this and in 

 former papers on other crops, those relating: to the pro- 

 portion of nitrogen recovered in increase, to that sup- 

 plied in manure for grass. But even with all the evi- 

 dence which the facts of the field will be able to 

 provide, the problem will still remain — of the exact 

 explanations to be given by science, of the loss which 

 is experienced by practice." 



THE USE AND ABUSE OF ALUM IN B READ-M A KI NG, 



Every now and then, of late years more especially, 

 we are terrified with some household cry. By some 

 means or another wc are found to be slowly, perhaps, 

 but systematically killing ourselves. We are liviusj; over 

 sewers ; have heavy curtains to our beds ; or arsenic- 

 tinted papering to our rooms. We delight to season 

 oar food with condiments that are little less than rank 

 poison ; and cling to essences and sauces that, like the 

 fox of the Spartan boy, are eating out our vitals. Even 

 the plaino.st fare is not without its alloy. Water itself j 

 is declared to be impure ; the best meat to be diseased ; 

 the fin(st bread "doctored," and the nicest beer 

 drugged. It is not only Damocles in Gi"osvenor-place 

 who sits down to dinner with this drawn sword of dan- 

 ger hanging over him. Tradesmen mutually return 

 the compliment one on the other; while Hodge carves 

 a crust that, if he did not bake it himself may bo as 

 much tampered with as anchovy paste or London 

 porter. 



Indeed, the sins of tlie baker are a very old story. 

 There is scarcely a man but who knows too well how 

 even the best bread is manufactured — how it comes to 

 look so white, and so fine, and so " crummy." Like 

 the state prisoner, who believes his doom is a secret 



death in his dungeon, he swallows every mouthful in 

 fear and trembling. Most probably there is something 

 wrong in it. Only when fir removed from cities docs 

 he brciithe again. Over the home-made heavy brown 

 loaf of his country cousin.s can he eat, drink, and be 

 merry. Ashe cuts the solid slice from off it, lie ejacu- 

 lates mentally, or may-be distinctly enough, "Ah ! this 

 is the thing ; there is no alum here I cin see." When 

 Coleridge's taciturn friend greeted the dumjdings as 

 " Them's the jockies for I !'' ho had, no doubt, been 

 suffering fiotn an attack on baker's bread. 



But after all, is alum this terrible cur.<o wo take it to 

 bo? Are wo really jusiifiid — as happened ere now — 

 on finding its presence in our quartern loaf, in rushing 

 off to the baker's house, and pulling it, oven and all, 

 about his ears ? Or shall we, more reasonably, be content 

 to indict him, and fine him, and ruin him ? Dr. Odling, 

 at a recent meeting of the Society of Arts, actually re- 

 quests us to pause ere we do anything of the sort. In 

 a paper ho read some fortnight since, on the chemistry 

 of bread-making, he discourses in this wise — He is 

 speaking of some secondary varieties : — " But these 

 flours, in proportion to their glucogenic tendencies, do 

 not make good broad, and it becomes an object with 



