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Professor Johnson in his report (Connecticut Experiment Station 

 1881) gives two methods; the one which he considers best adapted for 

 domestic use of any of the processes involving the use of oil of vitriol 

 is as follows: Take one hundred pounds of ground bone, such as con- 

 tains 20 to 50 per cent, more or less, of material coarser than would pass 

 through a sieve, having a one-half inch mesh, twenty-five pounds of oil 

 of vitriol, and six quarts of water. Separate the bone by sifting into 

 two, or if the proportion of coarse bone is large, into three parts, using 

 sieves of one-sixteenth and one-eighth inch mesh. Mix the coarser part 

 of the bone in a cast-iron or lead-lined vessel with the oil of vitriol. 

 When the bone is thoroughly wet with the strong acid add the water 

 stirring and mixing well. The addition of the water to the acid develops 

 a large amount of heat, which favors the action. Let stand, with occa- 

 sional stirring, for twenty-four hours, or until the coarser fragments of 

 bone are quite soft, then three grades of bone are used. Work in the 

 next coarser bone and let stand another day or two, until the acid has 

 softened all the coarse bone, or has spent its action; finally dry off the 

 mass by mixing well with the finest bone. 



In carrying out this process, the quantity of oil of vitriol can be varied 

 somewhat; increased a few pounds if the bone has a large proportion of 

 coarse fragments, or diminished if it is fine. 



Professor Stockhardt, the celebrated agricultural chemist, recommends 

 the following process: From a mixture of sifted wood or coal ashes and 

 earth thrown upon a barn or shed floor from a circular wall so as to 

 inclose a pit capable of containing one hundred weight of ground bone, 

 then make the surrounding wall of ashes so firm as not to yield by being 

 trodden on; sift off the finer part of the bone and set it aside; throw the 

 coarser part into the cavity and sprinkle it, during continued stirring, 

 with three quarts of water, until the whole is uniformly moistened; add 

 gradually eleven pounds of oil of vitriol of 60 degrees strength, the agi- 

 tation of the shovel being continued. A brisk effervescence of the mass 

 will ensue, which will not, however, rise above the margin of the pit if 

 the acid is poured on in separate small quantities. After twenty-four 

 hours sprinkle again with three quarts of water, add the same quan- 

 tity of sulphuric acid as before, with the same brisk shoveling of the 

 mass, and leave the substance to act for another twenty-four hours upon 

 each other; then intermix the fine bone previously sifted off, and finally 

 shovel the ashes and the earth of the pit into the decomposed bone until 

 they are all uniformly mixed together. 



It will be noticed that the last two processes use half or less than 

 half the usual quantity of acid allowed for a hundred pounds of bone. 

 The phosphoric acid in finely ground bone can also be made available 

 by the caustic action of the potash in unleached wood ashes. 



Professor Nichols recommends the following method: Take one barrel 

 rawbone flour, three barrels dry unleached wood ashes, ninety pounds 

 gypsum, and ten gallons of water; make a heap of the solid materials 

 on the barn floor, and add the water, stirring constantly with a hoe. 

 The result is perfect plant food, containing all the elements plants re-/ 

 quire in about the same proportions. 



Professor Pooling advises a little different method and proportions. 

 He recommends the following: Mix five barrels of finely ground bone 

 with five barrels of unleached hard- wood ashes, and add water sufficient 

 to moisten the mass, and then cover with loam. Leave the heap three 



