262 SUPERFHOSPHATE OF LIME. 



like a boiling pot. Stir away till the mass thickens too 

 stiff to move easily. Cover over with an old blanket and 

 wooden cover, and let all stand 24 hours, with occasional 

 stirring. 



On opening the tub after that time, a stiff, gray mortar, 

 moderately dry, will be found, which may be shovelled out 

 and spread thin in a warm dry place. In two or three weeks 

 it will dry so as to break down under a mullet or post-setter. 

 The finer dust may be sifted out and used for drilling in with 

 seed ; or the whole, before drying, may be softened and 

 broken down to an impalpable paste, in its weight of cold 

 water, and then mixed with the compost heap, at the rate of 

 100 lbs. of the dry mass to one cord of compost. Ordina- 

 rily, there is obtained from 100 lbs. of bone ash and 87| lbs. 

 of oil of vitriol, about 183 to 185 lbs. of superphosphate dry 

 enough to grind. It may be ground, after being cracked 

 small, in a grist mill, or still better, in a Bogardus mill, such 

 as is used for grinding ores. 



The drying of the crude mass may be hastened, and the 

 ease with which it may be pulverized promoted, by adding 

 to it, before removal from the tub, absorbent substances. 

 The best material is perfectly dry powdered peat or muck ; 

 or if obtainable, the charcoal cinders from locomotives at 

 railway stations. Fine dry spent tan will answer, or the 

 finest sifted parts of anthracite coal ashes. In lack of these, 

 bone ash itself may be used. Any of these, added and stir- 

 red well in till the mass dries and granulates, speedily puts 

 it into a state in which with slight drying, the mass will 

 easily pulverize. 



Supposing 183 lbs. have been obtained by thorough dry- 

 ing, the cost to the farmer who collects bones, or buys them 

 of the bone boiler at $6 per ton, will be as follows : 



