THE TECHNOLOGIST, [August 1, 1804. 



18 ON CHEMISTRY APPLIED TO THE ARTS. 



tion by the roots of plants, and of becoming at once available for their 

 growth. These suggestions of Liebig were rapidly carried ont on a 

 practical scale by Messrs. Muspratt, of Lancashire, and J. B. Lawes, of 

 Middlesex ; in consequence of the valuable results obtained by them, 

 the manufacture of artificial manures has gradually grown into an im- 

 portant branch of manufacture in this country. The manufacture of 

 superphosphate of lime is so simple that any farmer possessing a know- 

 ledge of the mere rudiments of chemistry can make it for himself, by 

 which he will not only effect great economy, but also secure genuineness 

 of product. All he requires is a wooden vessel lined with lead, into 

 which can be placed 1,000 lbs. of ground boiled bones, l,00Olbs. of water, 

 and 500 lbs. of sulphuric acid, sp. gr. 1.845 (or concentrated vitriol), 

 mixing the whole, and stirring well for about twelve hours. After two 

 or three days a dry mass remains, which only requires to be taken out 

 and placed on the land by means of the drill, or to be mixed with water 

 and sprinkled on the land. When very large quantities of this manure 

 are required, the plan devised by Mr. Lawes appears to me to be the 

 best. It consists in introducing into the upper end of a slightly- 

 inclined revolving cylinder a quantity of finely-ground boiled bones, 

 together with a known proportion of sulphuric acid of sp. gr. T68. As 

 the materials slowly descend by the revolution of the cylinder they 

 become thoroughly mixed, and leave it in the form of a thick pasty 

 mass, whicb is conducted into a large cistern capable of containing 100 

 tons, or a day's work. This is allowed to remain for twelve hours, when 

 it is removed, and is ready for use. Most manufacturers find it neces- 

 sary to add to the phosphate of lime of bones other sources of phos- 

 phates, such as coprolites, or the fossil dung of antediluvian animals, 

 which have been found in large quantities in Suffolk, Cambridgeshire, 

 and elsewhere, and contain from 36 to 62 per cent, of phosphate of lime, 

 and from 7 to 38 per cent, of organic matter. Others employ a mineral 

 substance called apatite, containing about 92 per cent, of phosphate of 

 lime, and found also in large quantities in Spain, Norway, France, &c. 

 Others, again, employ guanos rich in phosphate of lime, such as those 

 of Kooria Mooria Islands, and Sombrero phosphates. The following is 

 the average composition of the superphosphate of lime of commerce : — 



Soluble Phosphate 22 to 25 per cent. 



Insoluble „ 8 ,, 10 „ 



Water 10 „ 12 „ 



Sulphate of Lime 35 „ 45 „ 



Organic Matter 12 „ 15 „ 



Nitrogen 8'75 to i'5 per cent. 



The valuable and extensive researches of Messrs. Lawes and Gilbert, and 

 Messrs. Boussiugault and Ville, have not only demonstrated the import- 

 ance of phosphates to the growth of cereal and root crops, but also that 

 phosphates determine in a great measure during vegetation the absorp- 



