=Crushed Bone.=--The skulls, jaws and larger bones, are usually crushed before storing so as to get a greater weight in less space. In this condition they are ready for grinding into “raw bone meal,” the name given to ground bone for sale to glue makers for extracting glue. =Grinding Bone.=--Ground bone is usually ground through an attrition mill, of which there are several types. The mill delivers the grindings to a bucket type endless chain elevator, which in turn passes it through a screen--shaking or revolving--preferably the latter. The screen is usually about three feet in diameter by twelve feet long and covered with a screening of No. 16 wire, eight meshes per inch, which screens it to a size that will readily pass through a grain drill. The tailings or over sized bone is returned to the mill for further grinding. =Neatsfoot Oil Storage Tank.=--This is preferably a jacketed tank, one tank within the other, and must be made with a jacket to withstand the pressure that may be applied. Consequently the jacket should be reinforced with stay bolts so as to prevent distortion when pressure is applied. Any and all oil settling vats are best made cylindrical in form with a sharp cone at bottom. The cone is equipped for withdrawing sediment at the bottom and for withdrawing oil for purification sufficiently high in the cone to avoid withdrawing any sediment. =Neatsfoot Oil Purifiers.=--The same type of kettle or tank as described above is required, the latter being sufficient in size to accumulate a week’s work. =Yield Tests.=--The appended tests give the resulting yields from handling skulls and jaws, feet and shanks: TEST YIELD FROM SKULLS AND JAWS OF 1,209 CATTLE =========================+======+=======+====== | | | Per | |Average| Cent | | per | Green Products |Weight| head |Weight -------------------------+------+-------+------ No. 1 Ground Bone | 1972 | 1.63 | 9.48 No. 2 Ground Bone | 282 | .23 | 1.35 Bone Meal | 1381 | 1.14 | 6.64 Butter Stock Tallow | 1353 | 1.12 | 6.51 Bone House Tallow | 585 | .48 | 2.81 Pressed Tankage 50% water| 6512 | 5.37 | 31.32 =========================+======+=======+====== Total weight of feet from 1,209 cattle, 20,790.11 pounds. Average weight green feet per cattle, 17.19 pounds. TEST YIELD FROM FEET OF 1,391 HEAVY CATTLE