279 



by the acid, and thus some of the phosphate escapes decomposition, and 

 remains in the mass as insoluble phosphate; hence in the mass there 

 are always three constituents, the amount of which it is desirable the 

 farmer should know, viz: the soluble phosphate, (mono-calcic phosphate,) 

 the insoluble phosphate of lime, (undissolved bone earth,) and the sul- 

 phate of lime. These are the three important substances in a super- 

 phosphate, for although ammonia may be potentially present if raw 

 bones have been used, yet a superphosphate is not made or used for the 

 sake of the ammonia ; and when bone ash or burnt bone is used no am- 

 monia is required. 



If calcined bones, or the bone ash of the sugar-house, be the material 

 used, every 100 pounds will require 87^ pounds of vitriol ; when these 

 have fully acted on each other the mass would give : superphosphate of 

 ime, 2(j pounds; gypsum, 0(3 pounds; sulphate of maguesia, IJ pounds; 

 soda, 2f pounds, and the balance of the 187i pounds would be water and 

 undissolved bone earth. If the farmer uses steamed bones, a quantity 

 of vitriol intermediate between the two proportions named will be 

 needed, say GG pounds. 



The usual mode of making the fertilizer is to select a good wooden 

 floor of a barn, well covered overhead, or to make a box floor of thick 

 plank, laid tight. On this first throw the bones. If not in dust, it 

 would be well to sift the bones, and place the coarser part on this floor, 

 putting the finer portion aside for mixing in afterwards. By this means 

 the lough bone will come in contact with the strong acid first and be 

 more eflectually divided, while the finer parts can then be added to 

 dry up. 



No metal (except lead) should be used on the floor, or where the acid 

 can reach. Water equal to one-fourth or one-sixth the weight of bone 

 is then to be i)oured on the bone, well stirred in with a spade, and left 

 for two or three days to heat and ferment ; it would be well to use the 

 water boiling. Then add the sulphuric acid, mixing well with a wooden 

 spade or board ; the mass eflervesces, or boils ; stir twice a day well for 

 two days, so as to turn the whole mass over ; let it stand for two or 

 three days to dry ; add the fine bone and mix well. If not dry, use 

 some absorbing substance, as sawdust, dry peat, or dry earth, in small . 

 ciuautities, and mix well. Do not use for this purpose lime, ashes, or marl, 

 as they would destroy the superphosphate and spoil the whole work. 

 Made in this way from bone ash, this fertilizer will yield 30 per cent, 

 of soluble salts, of which 2G i)er cent, is superphosphate of lime. The 

 manufacturer will say that there is 35 to 37 per cent, of superphosphate 

 present, but he always over-estimates ; indeed, 20 per cent, of soluble 

 superphosphates is more than any farmer wants ; it is too soluble, and 

 will pass out of his ground too soon, especially in wet weather ; 12 to 

 15 per cent, is a better proportion for the farmer, for then he has a pro- 

 portionally larger amount of insoluble bone phosphate in store for fu- 

 ture use in the soil. On this account it is better for the farmer to use 

 raw or steamed bones than bone ash ; he has a sufiicient, though a 

 smaller, quantity of superphosphate present. 



This fertilizer will not sufler from exposure to air, but it must be i^ro- 

 tected from rain or wet ; it ought to be barreled up when not used im- 

 mediately. This fertilizer, made as directed, will be of a whitish color 

 if made from raw or steamed bone, and gray black if made from bone- 

 black of the refinery ; but the color of a sui>erphosphate is of no con- 

 sequence, and no test of its quality ; neither is its smell ; it ought to 

 have no smell, or a faint acid odor, if any. One ton of a manure made 

 by the farmer as directed is worth two purchased in the market. 



