^1-. -l^ ^ 



THE GENESEE FARMER. 189 ^^' 



above stated, 8 ©z. 7 drs. in urine. These figures indicate that 6 lbs. 2 oz. 6 drs. of 

 carbon escape in the form of carbonic acid from the lungs, less by the small amount 

 that passes off through the skin. As the quantity of carbon taken into the system was 

 12 lbs. 10 oz. 13 drs., it will be seen that one-half of all that enters the stomach is 

 literally burnt up to keep the body warm ; and of that taken up by the lacteals, tliree- 

 fourths are so consumed. To supply eight or ten pounds of soluble organized carbon 

 a day in the food of a cow, ox or horse, demands the best lights of organic chemistry. 

 If different animals give very unlike results, when fed in every respect alike, difterent 

 alimentary substances are still more varient in their nutritive powers and value, and 

 equally deserve close investigation. Anatomy, physiology and chemistry are dry sub- 

 jects to the uninitiated, but become interesting as one advances in them, and sees their 

 direct bearing on skillful husbandry. 



dj' 



SUPERPHOSPHATE OF LIME. 



We had supposed our readers would ere this have been tired of the very name of super- 

 phosphate of lime, but from the many inquiries we have recently received respecting its 

 manufacture, its real value, the crops which it most benefits, and the best manner of 

 application, we perceive that it is engaging the attention of some of our most intelligent 

 farmers, and that much ignorance and uncertainty prevails respecting it. 



Phosphate of lime is composed of phosphoric acid and lime. Phosphoric acid enters 

 into the composition of every plant that is grown for food ; it composes one-half of the 

 ash of wheat, maize, timothy seed, &c., &c. In conjunction with lime, it forms greater 

 part of the bones of men and animals. It will therefore be seen that phosphoric acid is 

 an element of great importance in an agricultural point of view ; and when it is remem- 

 bered that soils, though of the most fertile character, contain but a relatively small pro- 

 portion of phosphoric acid, its manurial value will be clearly understood. 



Phosphate of lime, as it exists in bones or in any of the mineral compounds, is insol- 

 uble in water. As plants take up all their food in solution, it is necessary to convert, 

 by decomposition or otherwise, this insoluble phosphate into a soluble one. Bi-phos- 

 phate of lime is soluble in water. That is to say^ a compound containing two atoms of 

 phosphoric acid united with one of lime, is soluble in water ; while phosphate of lime, 

 or a compound having but one atom of phosphoric acid united with an atom of lime, is 

 insoluble. The question then is, how shall we convert the phosphate into a bi or super- 

 phosphate of lime ? In the laboratory the change can be eflected by adding phosphoric 

 acid to phosphate of lime ; but this is too expensive a process to be applied to agricul- 

 ture. Another method, and the one adopted by the manufacturers of superphosj^hate 

 of lime, is to take away a portion of the lime of the phosphate of lime, setting free the 

 phosphoric acid combined with it. This free phosphoric acid unites with the remaining 

 phosphate of lime, and forms the required bi-posphate of lime. This is accomplished 

 by adding sulphuric acid to burnt bones or any phosphate of lime substance. Sulphuric, 

 being a stronger acid than phosphoric, takes away the lime and sets the phosiihoric 

 acid free, which, as we have said, unites with the remaining phosphate of lime, forming 

 the soluble phosphate required. 



Phosphate of lime is worth about seven mills per pound, as it can be purchased at 

 that price in most of o-ur principal cities in the form of animal charcoal. Bi-phosphate 

 of lime is worth about eight cents per pound. We do not say that farmers can 

 purchase it for that price, but they can manufacture it themselves for a little less 

 than that, and eight cents per pound is the estimated value in England, where it is 

 extensively used. 



dli 



