58 FERTILIZERS. 



phate of lime remaining. To make the phosphoric acid 

 in this fully soluble, we must treat it to sulphuric acid ; 

 though the results from burning the bones are, to reduce 

 the particles to so fine a state as to make them more or 

 less available without the use of acid. 



MAKING OUR OWN SUPERPHOSPHATE. 



Dr. Nichols, in his clear, practical " Barn-Floor Lecture," 

 gives, in substance, the following plan : Take a plank box 

 four feet square and one foot deep. This may be simply 

 water-tight ; but, if so, there must be no nails that the acid 

 can reach, for it will eat them out and so make a leak : or 

 it may be lined with lead, as the doctor directs ; all solder- 

 ing to be done with lead solder. The box will be large 

 enough to take a carboy of sulphuric acid, with the neces- 

 sary quantity of phosphate material and water to make 

 about a quarter of a ton of superphosphate. If we take 

 finely ground bone, the result, following the doctor's plan, 

 will be a pasty mass, needing mixing with muck, or 

 other dry material, to get it in good mechanical condition 

 for use. If, instead of bone, we use bone-black, as he ad- 

 vises, we shall have, as a result, a dry mass easily handled. 

 " To make our superphosphate," says Dr. Nichols, " a car- 

 boy of one hundred and sixty pounds of sulphuric acid or 

 oil of vitriol (sixty-six degrees strength), three hundred and 

 eighty pounds of bone-black, and ten gallons of water, 

 are needed. Having first donned old clothes, and having 

 at hand a little saleratus or some alkali, ready to rub on 

 any spot, should, by chance, a drop of the acid spatter on 

 our clothes or boots (for where it touches, if not immedi- 

 ately neutralized, it will char like fire), be sure to first 

 pour in the water, and then the acid ; next, slowly add the 

 bone, stirring it all the while with an old hoe of but little 

 value. There will be a great commotion, a great boil- 



