No. 7. 



Bone Dust — Phosphate of Lime. 



211 



Upon examination, it was ascertained that 

 what gave the efficacy to bones was the 

 phosphorus contained in them, connected 

 with an acid. It was not ascertained that 

 the animal portion of the bones was of no 

 importance ; but it was slower in its effects, 

 i n ameliorating the soil, than the inorganic 

 portion of the bones ; and that what was 

 mainly important, in the application of bones, 

 was to supply this inorganic portion in a 

 form that it should speedily be taken up. In 

 an ordinary state, this phosphorus was com- 

 bined with lime, in such proportions that it 

 was not easily dissolved : but, Professor 

 Liebig, to whom agricultural science is so 

 greatl}' indebted, discovered that, by the ap- 

 plication of sulphuric acid to the bones, a 

 portion of this lime would be abstracted, and 

 go into another form ; and a salt would be 

 left containing a much larger proportion oi 

 pliosphorus, — and so called the super-phos- 

 phate of lime, — which was soluble in wa- 

 ter, and would be at once taken up by the 

 plant. 



" Phosphate of lime is a substance very 

 difficult of solution : and thus, in a very dry 

 season, the effects of bones are slight and 

 imperfect. Super-phosphate of lime, on the 

 other hand, is extremely soluble, so much so 

 that the vitriolized bones can be entirely 

 dissolved or suspended in water, and thus 

 applied. This at once explains the cause 

 of the valuable properties of the preparation. 

 The bones in their natural state are ex- 

 tremely indigestible; the acid cooks them — 

 converts them into a species of soup, which 

 can readily be eaten and digested by the 

 young turnips. The adamantine fetters, 

 with which the various elements composing 

 bones are bound so compactly together, are 

 by means of this new agent burst asun- 

 der — the compact is broken, and each con- 

 stituent element is left to pursue its own 

 course, arid exercise its own natural affini- 

 ties."* 



The effects of this preparation of the 

 bones has answered every expectation ; and 

 where before sixteen and twenty bushels of 

 bones were applied to an acre, in the growth 

 particularly of turnips, four bushels, pre- 

 pared with sulphuric acid, are found now to 

 be even more effectual. The advantages 

 of such a preparation are very great, — first, 

 in stimulating and forwarding the growth of 

 the plant; next, in the cheapness of the appli- 

 cation; and next, in its so forcing the plant, 

 as soon to place it beyond the reach of the 

 fly, which never attacks it after the third 

 leaf is formed. 



*Spooner'3 Prize Essay. Journal of tlie Royal Ag- 

 ricultural Society, vol. vji. p. 1. 



The best mode of preparing the manure 

 has been matter of various experiments, and 

 deserves inquiry from the acrid nature of 

 the acid employed — the oil of vitriol. Mr. 

 Pusey advises, to erect a heap of fine mould, 

 and, forming a basin or crater in the centre, 

 to place the amount of bones to be dissolved 

 in it, and to apply gradually an amount of 

 sulphuric acid equal to half the weight of 

 the bone.^, which, after a short time, will 

 completely dissolve them; and then, shovel- 

 ling and mixing the mould together, the 

 manure will all be in a condition to be dis- 

 tributed by a machine in the drills prepared 

 for sowing the turnip seed. 



Mr. Tennant, of Shields, one of the best 

 farmers in Scotland, puts twenty-five bush- 

 els of bones into three old iron boilers, and 

 next pours in two bottles of acid, containing 

 one hundred and seventy pounds each, and 

 adds eighteen gallons of water to each 

 boiler. In a day or two they empty the con- 

 tents of the boilers into two cart-loads of 

 light mould, with which it is thoroughly in- 

 termixed ; and, being turned over three or 

 four times, after seVen or eight weeks the 

 compost becomes dry and mealy, and can be 

 spread by the hand. 



Mr. Spooner advises to place the bones in 

 a hogshead, and pour the acid upon them at 

 the rate of one third of the weight of the 

 bones in acid, that is, to one hundred and 

 eighty pounds of bones sixty pounds of 

 acid ; and, after it becomes sufficiently dis- 

 solved, to mix it with ashes, and apply it in 

 that form. He recommends, likewise, that, 

 first of all, the acid should be mixed with 

 one fourth of its weight of water, or perhaps 

 half as much water as acid, which will raise 

 it to the temperature of 300° Fahr., and 

 will much assist the dissolving process. Too 

 much care cannot be taken to guard against 

 the effects of the acid upon the clothes or 

 skin of the operator. 



The beneficial effects of this application 

 are now beyond question. Mr. Spooner cites 

 a case in which two bushels of vitriolized 

 bones, with ashes, gave as good a crop as 

 sixty bushels of bones unprepared. To 

 Swede turnips it seems more congenial and 

 efficient than to white turnips. Where the 

 crop of turnips is of so much importance 

 as here, this discovery is of immense conse- 

 quence. Whether it will be equally benefi- 

 cial to other crops, — to wheat or grain crops, 

 — is to be decided by further trials. The 

 experiments reported by one farmer, in re- 

 ference to a crop of carrots the second year 

 after its application, and to a field sown 

 with barley one year after its application, 

 showed most decidedly, so far, its permanent 

 I beneficial influence. 



