THE FARMERS' REGISTER. 



287 



animal matter. It must not touch them. It 

 spoils them. A layer of earth should be inter- 

 posed ; and then the lime would be highly use- 

 ful in catching and retaining the fertilizing vapor 

 as it rises. 



I believe ihere is no difference of opinion on 

 this subject among chemists. Humphry Davy 

 speaks in the plainest language against mixing 

 quick-lime with common dung as injurious; and 

 other eminent men fully accord with the doc- 

 trine. On the outside of the heap, however, 

 quick-lime in a few weeks would be carbonated ; 

 and after undergoing this change, it might be 

 safely mixed with the compost. A fresh coal 

 mav then be applied. 



But some farmers may not wish to apply their 

 barn yard manure in the spring, or make it into 

 compost — they may prefer using it after harvest, 

 and yet not have it wasting in the mean time. 

 In that case I would advise ihat it be thrown in- 

 ward where it lies ihin, just so far that this work 

 conjointly with the work of covering it, shall a- 

 mount to the least labor. Then cover the whole 

 with straw or earth to protect it from the sun ; 

 and cause it to be trodden down by the cattle as 

 firmly as possible to exclude the air, and prevent 

 fermentation. Some of you may recollect when 

 forking up such matters after harvest, that the 

 straw in spots was bright and unchanged. That 

 was where it was well trodden. All change is 

 attended "with loss ; but as some change may 

 be expected strew lime or marl and plaster plen- 

 tifully over it, to absorb, or arrest the fertilizing 

 vapor. 



The effect of plaster (composed of lime and 

 sulphuric acid) has long been a source of won- 

 der ; for it was a wonder how one bushel could 

 add more than 20 limes its own weight to a 

 crop of clover. Inquiring minds of course have 

 been busy in trying to explain the mystery; but 

 I douht if all the properties of this manure are 

 understood even at this day. Humphry Davy 

 was inclined to think that plaster was a neces- 

 sary part of the woody fit)re of some plants, 

 analogous to the bony matter in animal struc- 

 tures. The plant could not do without it, though 

 it wanted but little ; and hence so small a quan- 

 tity had such a powerful effect. "Plants which 

 seem most benefited by its application," says that 

 eminent chemist, " always afford it on analysis.'' 



When this theory was announced some thirty 

 years ago, it was rejected in this country, where 

 the effects of plaster were much better known 

 than in England, but if he could have shown 

 that it enters into such plants in any definite 

 proportion, some of the arguments against him 

 might have been refuted. It appears, however, 

 that he never pursued the inquiry with much 

 interest. 



Judge Peters of Pennsylvania had done more 

 than any other person to extend the knowledge 

 of this manure, and to lavor its introduction. 

 He had been very diligent and minute in his in- ' 

 quiries; and though not a professed chemist,! 

 became satisfied that sulphuric acid was the ac- j 

 live ingredient in plaster. He showed, from the ' 

 observations of Berard, that lands near Cutanea | 

 in Sicily, abounding in volcanic matter, including, 

 sulphur,* were very fertile ; and from an experi- 



* A late traveller writing from Italy, says of the 



ment by the same person, that brimstone, pound- 

 ed, sifted and mixed with ashes, had a surprising 

 effect on lucerne and clover. Sulphuric acid 

 greatly diluted with water, had a similar effect. 



Asa further confirmation of the effects of sul- 

 phur or sulphuric acid, when Chancellor Liv- 

 ingston was travelling in Flanders he saw the 

 farmers preparing pyrites tor manure. Thia 

 mineral is a combination of sulphur and iron, 

 and when partially burnt is employed in the same 

 manner, and lor the same purpose as we use 

 piaster. Dr. Chapman of Pennsylvania found a 

 similar result from sulphuret of baryies. 



Last summer, a new work called, Organic Chem- 

 istry, by Professor Liebig of Germany, was first 

 published in this country ; and it has been consi- 

 dered by those best qualified to judge, as consti- 

 tuting a new era in agriculture. It is not my in- 

 tention, however, to detain you with any of its 

 details, except his explanation of the effect of 

 plaster on growing plants. 



Ammonia is an essential part of the food of 

 plants. It affords all vegetables, without excep- 

 tion, with the nitrogen (hat enters in'o their com- 

 position. It is very volatile ; but sulphuric acid 

 (furnished by the plaster) can prevent its flight, 

 and fix it in the soil. This can only be done, 

 however, when the plaster is dissolved. The 

 sulphuric acid then unites with the ammonia, and 

 the carbonic acid of the ammonia unites with 

 the lime. 



Such is the purport of Professor Liebig's expla- 

 nation of this great mystery. If he is correct in 

 ascribing all* the effect of plaster to this new 

 combination, its importance in the economy of 

 our farms must be evident. All our fields, pas- 

 tures and meadows, ought to be strewed with it ; 

 and in accordance with his suggestion, it ought 

 to be scattered in all our siables, and over all our 

 barn yards. Tiie quantity required is not great ; 

 and many experiments may be instituted at a 

 trifling expense. 



I ought to say, however, that this theory ap- 

 pears insuflicient (or explaining all the pheno- 

 mena, in connexion with the use of plaster. Why 

 is its effect on clover so extraordinary, and on 

 wheat so insignificant ? Judge Peters, after using 

 it forty years, said he never found it beneficial 

 on winter grain ; and others, after long trials, 

 thought it did little for the natural grasses. All 

 these, however, are powerfully affected by stable 

 manure — by the very ammoniaf which that ma- 

 nure yields. And what do we observe? Clover 

 of luxuriant growth, and close along side of it, 

 wheat without any indication of benefit received, 

 though both have been plastered alike. 



Again — Professor Liebig informs us that every 

 shower of rain, or fall of snow, brings down am- 

 monia to the ground where the plaster ought to 

 arrest it, and the plants that feed on it ought to 

 be more thrifty ; but we have much testimony to 



peasants residing in the neighborhood of Vesuvius — 

 " If their houses are burned, they return, when the 

 lava cools, to build new ones, and cultivate a soil in- 

 exhaustibly fertile." 



* " The evident influence of gypsum upon the 

 growth of grasses depends only upon its fixing in the 

 soil the ammonia of tlie atmosphere." — Liebig, p. 142. 



t "Animal manure acts only by the formation of 

 ammonia."— Liebig, p. 136. 



