1870.] BROOME— ON CANADIAN PHOSPHATES. 249 



be shown in the increased jDroductiveness of many fields and 

 gardens upon the confines of London. 



With regard to bones, their employment as fertilizers cer- 

 tainly dates as far back as 1770 ;* and the supplies at present 

 required in England are chiefly derived from Germany, 

 Prussia, and the Baltic coasts. f The catacombs of Egypt 

 have actually been ransacked for their supplies of bones ; 

 and the mummies of her kings and warriors, scrupulously 

 preserved for a thousand years, have at length been sold by 

 their descendants, to aid in the nourishment of far off lands. $ 



Of the enormous importations of guano, nothing need here 

 be said, except that their annual amount is said to be 200,000 

 tons, with a value of about $12,500,000. 



The attention of Eno-lish merchants was first turned to 

 purely mineral sources of manures by the statement, made 

 by Liebig, in 1810, that, by treatment with sulphuric acid in 

 certain proportions, they could be converted into soluble com- 

 pounds ;§ and, two years later, J. JB. Lawes obtained a patent 

 for the preparation of superphosphates from the mineral 

 apatite, instead of from bones, which had even then reached 

 a high price. II The supply of mineral phosphates was at first 

 drawn from the great deposits of Estramadura, in Spain, 

 (^Vide table vi., for analysis of the phosphates from that 

 locality) ; but the better kinds of the mineral were soon, to 

 a great extent, exhausted, and the attention of manufacturers 

 was then directed to the coprohthic phosphates — or fossilized 

 exuviae of the tertiary strata of Sufiblk, and the older rocks of 

 Cambridgeshire and North Wales, all of which are compara- 

 tively poor in phosphates, containing only from 30 to 50 per 

 cent, of phosphate of lime. In 1854, the value of the " super- 

 phosphates^^ manufactured from mineral sources in England 



* See the works of Arthur Young, published about 1770. 



t Vide Richardson and Watt's Chemical Technology, vol. ii., article 

 " Soluble Phosphates." 



X Had Shakespeare lived in the nineteenth century, there would have 

 been an awful significance in the words — " Cursed he he that moves my 

 hones .'" 



$ Vide Liebig's Lectures on Agricultural Chemistry. 



II Vide Specifications for British Patents, 1842. (N"o. 9,253, May 23rd) 



