294 Mr George Fownes on the Existence of 



both directions, yet, even in this case, the tendency to arrange itself 

 according to the laws which regulate inert matter might operate too 

 powerfully, were it not diminished by the association, in equal atomic 

 weiglits of the two phosphates, each of which possesses a polarity in 

 some degree differing from the other, and consequently, to a certain 

 extent, counteracts the disposition in the particles of the other to 

 assume a determinate arrangement. 



If there be any truth in these speculations, is it not also conceiv- 

 able, that the interposition of a mineral matter, like fluor-spar, whose 

 particles crystallize in quite another manner, that is in cubes, may 

 co-operate on the same principle, in imparting that freedom of motion 

 to the particles of the prevailing constitutent of bones, by which it 

 is rendered more pliant to the purposes of the animal economy, more 

 obedient to the laws of life, more ready, in short, to insinuate itself 

 into the pores, so as to form the coats of those delicate capillary 

 canals, of which the osseous structure appears to consist ? — Philoso- 

 phical Magazine, vol. xxv. !N"o. 164, p. 122, 



On the Existence of Phosphoric Acid in Rocks of Igneous Ori- 

 gin. By George Fownes, Ph. D., Chemical Lecturer in the 

 Middlesex Hospital Medical School. Communicated by 

 Thomas Graham, Esq., F.R.S., &c.* 



The important, though obscure, functions attributed to the ele- 

 mentary body, phosphorus, both in the vegetable and in the animal 

 kingdoms ; and the well known fact, that rocks of nearly every de- 

 scription afford, on disintegration, soils more or less capable of sup- 

 porting the life of plants, and from which, consequently, phosphoric 

 acid cannot possibly be absent, seemed to render a search for that 

 substance, in rocks of igneous origin, generally very desirable, be- 

 cause if there found, an easy and satisfactory explanation of the 

 origin and first source of the element in question would be given. 

 As I am not aware that any direct researches on this subject have 

 yet been made, or at least placed on record, I venture to submit to 

 the notice of the Royal Society, the results of a ^^yt experiments 

 made by myself, which, so far as they go, resolve the question in 

 the affirmative. 



The first substance tried was the fine white porcelain-clay of Dart- 

 moor, Devon, the result of the disintegration of the felspar of the 

 granite of that district. This is one of the chief components of por- 

 celain, and of the finer kinds of English earthenware, and was found 

 on analysis to correspond very closely in composition with that of 

 the material employed in the manufacture of the Sevres porcelain. 



* Phil. Trans. Royal Soc. London. Year 1844. Part I., page 53. 



