Mr. P. Cooper's Notice of a Theory of Molecular Actio7u 355 



All circumstances considered, I fear we can only regard 

 Mr. Marsh's very ingenious test for arsenic as furnishing good 

 collateral evidence, capable indeed, in scientific hands, of giving 

 very correct indications, but wholly unfit to be entrusted to those 

 unaccustomed to careful chemical manipulation. 1 say this 

 with a thorough conviction of the great utility of Mr. Marsh's 

 test, and am only sorry that its evidence is not unequivocal. 



Roebuck Place, Yours, &c., Lewis Thompson, 



Great Dover Road. M.R.C.S. 



LXIX. Notice of a Theory of Molecular Action. 

 By Paul Cooper, Esq, 



To the Editors of the Philosophical Magazine and Journal. 



Gentlemen, 

 ¥ N the Philosophical Magazine for April, p. 320, you have given 

 "■■ a notice of the researches of M. Mossotti relative to the laws 

 of molecular action ; may I beg the favour of your directing 

 the attention of your readers to an equally simple and much 

 more comprehensive theory on the same subject, a sketch of 

 which I published in a small pamphlet* some months since? 



"1. In this theory it is assumed, that bodies are formed of 

 matter, consisting of globular atoms of different sizes, having 

 an attraction for each other in the direct proportion of their 

 bulk, or quantity of matter, and inversely as the square of 

 their distance ; and of light, consisting of globular atoms, 

 constantly separated by a repulsive force, regulated by the 

 same law of distance, uniform in size, and much smaller than 

 the atoms of matter ; for which they have an attraction, also 

 regulated, both with regard to distance and dimensions, by 

 the laws already mentioned. 



" 2. The light under the influence of these laws must sur- 

 round the atoms of matter, forming what we have called an 

 atmosphere about each atom, and this atmosphere will be held 

 in its position by various degrees of force, which will draw the 

 atoms of light nearer to each other as they approach the atom 

 of matter, and thus give it greater intensity (density). The 

 atmosphere, it is supposed, will be divided into strata of dif- 

 ferent intensities, forming concentric spheres ; every atom of 

 light at equal distances from the centre being held in its po- 

 sition by equal forces." 



"^. The point of saturation, under ordinary circumstances, 

 will be when the repulsive force of the light is sufficient to 

 counteract the attraction of the central atom of matter ; when, 

 with the exception of the attraction of the atoms of matter for 



* Abstract of a series of papers, entitled *' Outlines of a theory intended 

 to connect the operations of nature upon general principles." 



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