FERTILIZERS. 59 



ing and frothing and foaming and thro wing-off of heat 

 with a suffocating vapor, which will make you think for a 

 moment that you have drawn your last breath. But have 

 courage : there have been a few millions of tons made be- 

 fore your day, and the men who made them yet survive. 

 Because of the suffocating vapor, it is well to do the work 

 in the open air or in an open shed. 



In the report of the Connecticut experimental station 

 (1881), Professor Johnson gives two methods. That pro- 

 posed by Dr. Alexander Miiller, Professor Johnson thinks 

 the one best adapted for domestic use of any of the pro- 

 cesses involving the use of oil of vitriol : " Take one hun- 

 dred pounds of ground bone, such as contains twenty 

 to fifty 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 thor- 

 oughly 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 occasional stirring, for twenty-four hours, 

 or until the coarser fragments of bone are quite soft; 

 then, if 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 frag- 

 ments, or diminished if it is fine." 



