THE FARMER'S MAGAZINE. 



109 



composition, are ready-formed ammonia; substances contain- 

 ing nitrogen; and alkaline matters, more especially potash, 

 are tlie most universally efficient manures. These are also the 

 more expensive raauurinj; constituents, so that to some extent 

 the practical and commercial value of artificial manure go hand 

 in-!iaud; but, on the other hand, it would be wrong always to 

 determine what you should pay for artificial manure hy the 

 effect which it produces. lu some cases he had seen super- 

 phosphates applied upon lands which contained in themselves 

 a large quantity of phosphates, and tlierefore the extra supply 

 did no pood whatever. Tnese, however, were exceptional cases, 

 ar.d did not often occur. The question— and a very important 

 oi;e it was — then aros'e: what description of manure o ght 

 you to use ? and secondly, what ought you to pay for a ma- 

 nure of a certain character ! No person should understand so 

 well as the farmer himself what is really required for his par- 

 ticular farm ; and in practical matters no fixed rule can be 

 laid down. Some general hints may be thrown out which 

 have been collected from a number of experieu';e3 in various 

 districts, which are useful as a basis ; and it is from the expe- 

 rience of farmers living in many counties in England and Scot- 

 land we know that, generally speakmg, ammoi.iacal or nitro- 

 genous matters are peculiarly beueficial to corn crops. In 

 making th s statement, he kfc entirely untouched the ques- 

 tion whether miaeral substances are not an advantage in some 

 instances for corn. He knew that they were. But, on the 

 whole, substances rich in nitrogen arc applied with great benefit 

 to corn crops. Hence good rotten dung was better than fresh 

 manure, because weight for weight it contained a larger 

 amount of nitrogen. He wished them to understand that he 

 did not recommend well-rotted dung under all circumstances; 

 because it was genera ly better to take the manure as fresh as 

 possible, and get all that was valuable out of it upon the land. 

 But because rotten mauure contained a larger amount of nitro- 

 gen in the shape of ammoniacal salt, it generally produced 

 greater effects than the fresh. So with guano— a small quan- 

 tity of this produced such extraordinary result-, because it 

 contained in one cwt. as much ammonia as a ton of well- 

 rotted farmyard msnure. The effect of manures did not depend 

 upon anything mysterious. Manure from half-starved animals 

 would never be very good, no matter how much it was turned, 

 and it was not the mere rotting that made it good. In good Peru- 

 vian guano there was from 16 to 17 per cent, of ammonia. 

 It was important that they should recollect that there was 

 a great difference between good Peruvian guano and that 

 which had been brought over since the best layers had been 

 cleared away. In good guano there was also a large propor- 

 tion of phosphates or bone earth. The solid part of bones 

 consists of phosphoric acid and lime, and this would explain 

 why it IS that good guano produces a good effect upon tur- 

 nips. Experience had likewise shown that phosphoric ma- 

 ntirej were especially beneficial to root crops — bone dust 

 and some inferior kinds of guano, having phosphate of lime 

 as their characteristic constituents, were the manures best 

 adapted to turnips, mangolds, et cetera. Alkaline salts was 

 a very gotd mauure for root crops. It would be admitted by 

 all who had any experien"e in the application of artificial 

 manures, that guano and superphosphate were the two most 

 valuable, in a commercial point of view, that could possibly 

 be used in agriculture. Guano, it was well known, was the 

 most successful agency they could apply to wheat or grain 

 and grass lands, while superphosphate was most applicable to 

 roots. Saliianha guano, widch was cheaper than the best 

 Peruvian, produced a belter result when applied to roots, 

 because it contained more phosphate. If they depended en- 

 tirely upon guano they would have too much leaf and not 

 sufficient bulk. A series of experiments which he had con- 

 tinued for four years convinced him that they could not dis- 

 pense entirely with ammonia for root crops, but it produced 

 frequently more harm than good. To spend, therefore, a 

 large sum in buying ammonia (which is a very expensive 

 material) for root crops was to make a great practical blun- 

 der ; for pliosphate was one-seventh the cost, and produced 

 infinitely better results when applied to roots. Commercially 

 speaking, ammonia is the most expensive ingredient used in 

 superphosphates. Alkaline salts, which are occasionally 

 found in artificial manures, are hkewiso expensive materials 

 — too expensive, in fact, to be used with advantage in agri- 

 culture. For this reason most artificial manures do not con- 

 tain any appreciable quantity of these expensive salts — the 

 effect they produce upon the land is not commensurate with 



their cost. Bearing in mind, then, that the value of artifi- 

 cial manures is to be estimated by the amount of nitrogen 

 (ammonia) and phosphates which they contain, there wo'.ld 

 be no difficulty in applying this test to the different manures sold 

 to farmers. The Economic Manure, to winch he had referred, 

 contained very little of these ingredients. A satnp'e of Mexican 

 guano (as would be seen from tlie diagram) contained only 18 

 per cent, of phosphate of lime (unc-third of that contained in 

 bone dust) and a mere trace of ammouia. Another manure, 

 advertised as the very esbence of Peruvian guano, consisted 

 chiefly of burnt clay, carbonate of lime, and a little sheep's 

 dung. (Laughter.) The learned professor tlien directed 

 attention to the diagrams showing the compos tion of the 

 best guano (for corn) and the best superplioaphaies for root 

 crops. These manures varied considerably in llieir cuiupo- 

 nent parts, and their effect when applied to the land iiiust 

 also be vastly different In one of the samples it would be 

 seen that there was not more than a fourth as much phos- 

 phate as that contained in another sample. In the highest 

 there was no less than 40 per cent, of soluble and insoluble 

 phosphates, and this could not be sold for less than X12 per 

 ton. With this exception the other manures — though vary- 

 ing so much in quality — were about the same price, from £6 

 to £7 10s. How could you ascertain which really was the 

 most valuable article ? To take it up, and smell it, in order 

 to discover its quality, was simply ridiculous. In the course 

 of the year he examined some huudred specimens of super- 

 phosphates ; yet he had not yet attained to that practical 

 acquaintance with it to be able by looking at it to ascertain 

 whether it was good or bad. They all looked very much alike, 

 and smelled more or less disagreeable. lu nine cases out of 

 ten, as he had said, the farmer wants either guano or super- 

 phosphate, and he should confine himself to these manures. 

 As to guano, when farmers buy this they ought to receise in 

 writing a guarantee that it really is genuine Peruvian with 

 which they are supplied. But if there is any suspicion, a very 

 simple test would pruve whether it is well groundeii or not. 

 A trustworthy opinion of its genuineness could he obtained at 

 the moderate expense of seven or eight shillings. Without 

 this, however, good Peruvian guano has such marked qualities, 

 and varies so little in its composition, that any one may for 

 himself ascertain its quality. When burned it should leave 

 one-third of itself a perfectly white ash — adulterated guano 

 produces more ash, and is coloured ; this ash, on being dis- 

 solved in acid, should leave no perceptible amount of sand. 

 At any rate, it would be easy to obtain in writing from the 

 dealer a guarantee that what he supplied is genuine. Super- 

 phosphate is a manure that can be produced in a variety of 

 ways, its efficacy depending, unlike thut of guauo, on the 

 amount of phosphates it contains ; and not only upon the 

 amount of material, but upou the state of preparation it has 

 undergone. Between soluble and insoluble phosphates there 

 was a great difference, not only in their efficacy, but in 

 the expense to which the manufacturer is at to produce 

 them. Manuring constituents to enter into plants must be- 

 come soluble ; phosphates, when in a condition to be readily 

 taken up by plants, must be far more efficacious than the same 

 constituents in a state in which they cannot be absorbed by 

 the rootlets. To illustrate this, a valuable raw material was 

 coprolife, or fossil remains, which had been not altogetlier cor- 

 rectly termed coprolites. That term signified the petrified ex- 

 crement of animals ; but the substances known as roprolitea 

 were in reality the fossil bones of those animals which in dis- 

 tant ages inhabited the regions where they were found. 

 They were also more correctly known by the name of pseudo- 

 croprolites, and were in reality nothing more than fossil bones. 

 With regard to their composition he might observe that they 

 did not contain any organic matter ; they contained only 

 mineral substances, and amongst others plio ph-ite of lime. In 

 its crude state, however, this phosphate was of no use what- 

 ever ; it produced no effect, no matter how finely it was pow- 

 dered. He had tried it repeatedly, some eight years ago; and 

 although finely powdered, it remained insoluble, even when 

 attacked by acetic arid. Hence there was always some risk of 

 having a portion of insoluble and useless material in aupcr- 

 phospnatcs. Bones were rendered only soluble by expending 

 large sums of money in buying expensive acids; hence soluble 

 bone earth is worth at least three times as much as it is in its 

 crii'le state as insoluble phosphate. It may be asked if, when 

 these acids came into contact with the tender fibre of the 

 plant, would they not be injurious to it? There wap, however, 



