SECRETARY'S REPORT. gg 



thirty-five per cent,; of rye, forty-six per cent.; of Indian corn, 

 thirty-nine per cent.; of oats, eighteen per cent., or if the husk be 

 first removed, forty-four per cent ; hence, the necessity of an ade- 

 quate supply in order to secure satisfactory crops. 



There is an obstacle in practice, but not an insurmountable one, to 

 the application of bones in such a way as economically to supply 

 the want, arising from their toughness and solidity in their natural 

 state. To pound them up finely by hand, is a tedious and difficult 

 undertaking. To burn them to ashes, involves the loss of the organic 

 matter; to dissolve them in acid, without first being reduced to 

 powder, is rather too costly, and not a very easy process. 



Various mills and other contrivances have been made for crushinnc 

 bones, and whenever their value is properly appreciated, some appara- 

 tus will be introduced into every section for this purpose. 



The machinery most approved in England for crushing bones, 

 consists of two or more sets of rollei;| or cylinders, with serrated 

 surfaces, fixed in a frame-work, and adapted to the ordinary gearing 

 of horse or steam power, with a hopper for the bones, which, after 

 passing through one set, pass through the next, which have closer 

 teeth, and crush them into smaller pieces. There are also wire 

 cylinders which act as riddles, the meshes of which are adapted for 

 the purpose of retaining the larger particles, while the smaller fall 

 through. I saw at St. John, N. B., a bone mill constructed on this 

 principle, but with only a single pair of rollers or cylinders with 

 serrated surfaces, which answered the purpose, but required that 

 the bones be passed through several times. An apparatus of this 

 sort should be both powerful and weighty, in order successfully to 

 overcome the resistance of the bones, and crush them to a proper 

 degree of fineness. 



By the addition of sulphuric acid, in the proportion of one part 

 by weight of acid (diluted with an equal quantity of water) to two 

 parts of ground bone, we secure the combination of the acid with a 

 portion of the lime, leaving the other combined with a double pro- 

 portion of phosphoric acid. This is called biphosphate or superphos- 

 phate of lime, and differs from the phosphate as existing in bones, 

 in being much more readily soluble, and so producing immediate 

 effect — a very small application thus sufficing for the wants of one 

 crop. If bones be crushed so that the largest pieces will not exceed 



