Aug-ust 1, 1864.] THE TECHNOLOGIST. 



ON CHEMISTRY APPLIED TO THE ARTS. 17 



Berzelius was the first to establish the fact that phosphate of lime was 

 the only substance possessing the properties necessary for the formation 

 of bone, owing to the extremely simple chemical reactions which cause 

 the soluble phosphates to become insoluble. Let us trace shortly the 

 sources from whence we derive the large proportion of phosphate of 

 lime which exists in our frames. Several of our most eminent chemists 

 have proved the existence of phosphorus in sedimentary and igneous 

 rocks, and the important part played by phosphorus in nature cannot 

 be better conveyed to your minds than by this extract from Dr. Hof- 

 mann's learned and valuable ' Report on the Chemical Products in the 

 Exhibition of 1862 :' — " Large masses of phosphorus are, in the course 

 of geological revolutions, extending over vast periods of time, restored 

 from the organic reigns of nature to the mineral kingdom by the slow 

 process of fossilization ; whereby vegetable tissues are gradually trans- 

 formed into peat, lignite, and coal, and animal tissues are petrified into 

 coprolites, which, in course of time, yield crystalline apatite. After 

 lying locked up and motionless in these forms for indefinite periods, 

 phosphorus, by further geological movements, becomes again exposed 

 to the action of its natural solvents, water and carbonic acid, and is 

 thus restored to active service in the organisms of plants and lower 

 animals, through which it passes, to complete the mighty cycle of its 

 movements into the blood and tissues of the human frame. While 

 circulating thus, age after age, through the three kingdoms of nature, 

 phosphorus is never for a moment free. It is throughout retained 

 in combination with oxygen, and with the earthy or alkaline metals, 

 for which its attraction is intense." After these eminently philosophical 

 views by Dr. Hofmann, I will proceed to call your attention to the appli- 

 cation of bones to agriculture. Bones are generally used for manuring 

 in one of these three forms : — 1st. As ground green bones ; 2nd. As 

 ground boiled bones (that is, bones nearly deprived of their osseine by 

 boiling under pressure, as I shall describe in my next lecture) ; 3rd. 

 Superphosphate of lime. 



Green or raw bones have been used on grass land for a long period, 

 but their action is exceedingly slow and progressive, owing to the 

 resistance of the organic matter to decomposition and the consequently 

 slow solubility of the phosphate of lime in carbonic acid dissolved in 

 water. What substantiates this view is, that boiled bones are far more 

 active than the above. It is found that from 30 to 35 cwts. per acre of 

 these will increase the crops on pasture land from 10 to 20 per cent, in 

 the second year of their application. But the great advantage which 

 agriculture has derived from the application of bones as a manure has 

 arisen from their transformation into superphosphate of lime, especially 

 applicable to root and cereal crops. To Baron Liebig is due the honour 

 of having first called the attention of farmers (in 1840) to the import- 

 ance of transforming the insoluble phosphate of lime of bones into the 

 soluble superphosphate, rendering it susceptible of immediate absorp- 



VOL. V. D 



