J>Jo. 1. 



Essays on Agriculture. 



21 



in for the use of a crop* In this dase, though 

 it would decompose much more slowly, and 

 produce less effect at first, yet its influence 

 would be much more lasting'. 



Manures from animal substances, in jrene- 

 ral, require no chemical preparation to fit 

 them for the soil. The great object of the 

 farmer is to blend them with the earthy 

 constituents in a proper state of division, and 

 to prevent their too rapid decomposition. 



By covering dead animals with five or six 

 times their bulk of soil, mixed with one part 

 of lime, and suffering them to remain for a 

 few months, their decomposition would im- 

 pregnate the soil with soluble matters, so as 

 to render it an excellent manure, and by 

 mixing a little fresh quick lime with it at the 

 time of its removal, the disagreeable effluvia 

 would be in a great measure destroyed ; and 

 it might be applied in the same way as any 

 other manure to crops. 



The refuse of the different manufactures 

 of skin and leather form very useful ma- 

 nures; such as the shavings of the currier, 

 furrier's chippings, and the offals of the tan- 

 yard and of the glue-maker. The gelatine 

 contained in every kind of skin is in a state 

 fitted for its gradual solution or decomposi- 

 tion ; and when buried in the soil, it lasts for 

 a considerable time, and constantly affords a 

 supply of nutritive matter to the plants in its 

 neighborhood. 



[To be continued.] 



For the Farmers' Cabinet. 



Essay§ on Asriciilture.— Wo. VI. 



BY JOSEPH CLOUD. 



As the object of the use of calcium in ag- 

 riculture is that of obtaining an increase in 

 quantity and perfection of vegetation, which 

 the result of long practical experience and 

 extensive use seems to justify — the impor- 

 tant question naturally presents itself — how 

 does it operate to produce that effect. If this 

 was better understood, it would reflect mucli 

 light on the subject of the most judicious use 

 as to quantity and mode of application. It 

 has been suggested that it is probably in it- 

 self one of the essentials of the food of plants, 

 and that by its union with carbon and other 

 important materia! of vegetation they are in 

 a state of preparation to be received as nour- 

 ishment. Tliese views of the subject will be 

 particularly noticed in the consideration of 

 the food and growth of plants. It is also 

 probable that it may act as a septic and pro- 

 mote putrefaction. The hydrate in a state of 

 solution, being absorbed by the putrescent 

 matter and consequent exposure to the in- 

 fluence of carbonic acid, it necessarily becomes 

 coacrete particles of carbonate, which be- 



ing interposed between particles of the pu- 

 trescent matter, in some degree destroys 

 their attraction of aggragation, thereby pre- 

 senting the unprotected particles to tho 

 more direct influence of oxygen, the great 

 agent in promoting putrefaction. An excess, 

 however, of calcium, would prove an anti 

 septic and prevent decomposition by an accu- 

 mulation of the particles of insoluble carbonate 

 of calcium, a protection would be formed pre- 

 venting the access of oxygen to the putres- 

 cent matter and preventing decomposition 

 similar to the effect produced by white wash- 

 ing. Calcium may also produce a considera- 

 ble mechanical effect in changing the texture 

 of soils, rendering them more or less retentive 

 of moisture, the particles becoming carbo- 

 nates and interposing between the particles 

 of silex and alumine; in the first case lessen- 

 ing the distance, and in the other increasing 

 it — the eff'ect produced is necessarily the re- 

 sult. No chemical union taking place, the 

 particles of carbonate remaining distinct and 

 separate bodies possessing the power of ab- 

 sorbing carbonic acid until they become su- 

 per carbonate. Thus, after having served to 

 qualify the texture of the soil and treasured 

 up a quantity of the food of plants, they be- 

 come soluble in water, and in common with 

 the other essentials of their necessary food to 

 be taken up by the absorbing roots and con- 

 ducted into the general circulation, where 

 they are appropriated to their respective uses 

 by the operation of the laws that govern ve- 

 getable organization. 



The diversity of opinion prevailing respect- 

 ing the quantity of calcium that may judi- 

 ciously be used per acre, and the best mode 

 of application renders it a subject meriting 

 consideration. Not presuming to direct or 

 prescribe rules for the government of others, 

 it is however, suggested, that thirty to thirty- 

 five bushels may probably be found sufficient 

 for a single application. That quantity would 

 doubtless be sufficient to receive and retain 

 all the carbonic acid that could be presented 

 from every source during the usual period of 

 rotation of crops. It is believed to be desira- 

 ble to retain it as much on or near the surface 

 as possible, thereby promoting its facility in 

 combining with carbonic acid presented by 

 the atmo-phere, and also that produced by the 

 decomposition of the putrescent matter in the 

 earth, which could not be so extensively ef- 

 fected if buried deeper than the putrescent 

 matter, the carbonic acid by its elasticity and 

 consequent ascension would escape the action 

 of the calcium and be lost. Another import- 

 ant reason in favor of the surface is, that 

 when it arrives at the state of soluble super 

 carbonate, it is more directly exposed to the 

 influence of moisture, and in closer connec- 

 1 tion with the absorbent roots of vegetables. 



