THE FARMERS' REGISTER. 



105 



ing its slow decay to yield about 30 lbs. of ammo- 

 nia to the soil. I'have not taken this into account, 

 because the special and immediate aciion of guano 

 seems to depend upon its containing, like tarm- 

 yard manure, ammonia ready Ibrnied, and thus 

 prepared to act without delay on the plant lo 

 which it is applied. That growth which the 

 ammonia of the sal ammoniac m our mixture is 

 fitted to hasten and provoke, the ammonia which 

 is afterwards slowly evolved from the decaying 

 animal matter will carry forward and help on to 

 maturity. The few pounds of potash in the mix- 

 ture have been added, not because this substauce 

 is always present in the guano, but because it is 

 known ihatnearly ail plants require a certain small 

 quantity of this alkali lor the perfect developemeiit 

 of their several parts. Another advantage which 

 will be possessed by the artificial mixture will be, 

 that its constitution will be constant, and may 

 always be calculated upon. 



From these theoretical considerations, therefore, 

 we should say that until its virtues are proved to 

 be greater, beyond dispute, than those of the 

 above or similar mixtures, the practical larmer 

 ought not to purcnase guano at a higher price 

 ihan 20s. per cwt., a price which in the opinion 

 of Mr. Pusey the farmer may probably aftbrd to 

 pay — which according to Mr. VVinterfeldt would 

 more than remunerate the importer — and below 

 which, according to the chemist, an artificial 

 guano of equal efficacy may be prepared in If^ng- 

 land, af\dfro7n the superabundant produce of our 

 own manufactories. 



Of comparative experiments with guano and 

 other manures. — But the absolute value of guano 

 Itself, as well as its relative value compared with 

 other manures, can only be placed beyond dispute 

 by actual and comparative trials of its efficacy in 

 ditferent soils and upon difJerent crops. To be 

 really uselul and satielactory these trials must be 

 made according to some well-digested method, 

 and the comparison must be made with known 

 weights of other substances, the action and money 

 value of which are known, and which from their 

 constitution may be supposed to act on vegetation 

 in a similar way. As 1 have elsewhere endeavor- 

 ed to draw the attention of practical men to the 

 importance of well-devised and carefLilly executed 

 experiments in practical agriculture* — not only to 

 the general economy of the art of culture, but also 

 to the establishment of a true theory of its various 

 processes — I shall take the liberty ol introducing a 

 few suggestions in regard to the kind of experi- 

 ments which appear to me most likely to yield 

 results at once economically and theoretically 

 useful. 



Among those substances which owe one main 

 part of their beneficial agency on vegetable life 

 to the ammonia they contain or evolve, may be 

 reckoned farm-yard manure, crushed bones, and 

 rape-dust. As the nitrates also act upon plants 

 in a way so liar similar to ammonia as to yield 

 nitrogen to them, the nitrates of potash and soda 

 may be included in the list of substances with 

 which it would be desirable to compare the aciion 

 of the guano. The cost of all these substances 

 is known,— they are all to a certain extent m 



* See a small tract published by Blackwood, under 

 the title of " Suggestions for experiments in practical 

 agnculture." 



Voh. X.-14 



general use, — and while comparative experimenla 

 accurately made by weight and measure would 

 throw light on many obscure points in regard to 

 the action of each of these manures, — the results 

 obtained from every separate plot of ground would 

 serve as so many points of comparison by means 

 of which the absolute and relative value of the 

 guano might be determined. 



In the present state of our practical knov\ ledge 

 respecting this substance, it will be pronounced 

 by every one to be desirable that its effect should 

 be tried upon every kind of crop ; but the pro- 

 priety of this course is increased by our know- 

 ledge of its chemical constitution. It contains 

 the greater part ot' the ingredients which are ne- 

 cessary to the growth of almost every variety of 

 crop. It will doubtless prove as efficacious there- 

 fore to old pasture-land as to the rye-grass in Mr. 

 Skirving's nursery, and to crops of corn as to 

 Mr. Pusey's turnips ; but experience alone can 

 tell us to which it may be applied with profit to 

 the larmer, and fi"om what crops it will afford 

 him the greatest return on a given soil. 



1 would propose therefore that it should be 

 tried during an entire rotation to replace farm- 

 yard manure and the other substances named, 

 as well as against the mixture above described, 

 which I shall distinguish by the name of arti- 

 ficial guano. The mode of making the experi- 

 ments may be varied at the wish of the practical 

 farmer, but they might be made in a way simi- 

 lar to that represented beneath, each square be- 

 ing a half or quarter acre or other accurately 

 measured plot of land. 



The practical farmer need not be deterred by 

 the formidable array of experiments above sug- 

 gested. He may try any two or three of them, 

 and his results will be valuable in proportion to 



