Messrs. Playfair and Jottle on Atomic Volume, S^c. 4^^ 



ment of phosphorus CKhibiting a very large surface, if coir^^ 

 pared to the volume of air passing at a time over that phosphor 

 rus, it is manifest that under those circumstances, ozone, imme- 

 diately after its having been formed, must have been taken up 

 again by the substance under whose influence it was produced., 

 Ozone disappears also, only a little more slowly, if into a 

 bottle containing ozonized air a common piece of phosphorus 

 is. placed, and that bottle happens to be closed air-tight. In 

 that case ozone is destroyed and re-formed as long as there 

 are free oxygen, water or aqueous vapour and phosphorus in 

 contact with one another. The last trace of oxygen being 

 transformed into ozone, and nothing left but nitrogen and 

 ozone, the latter will soon be entirely absorbed by phospho- 

 rus, and the bottle contain nothing but nitrogen and the phos- 

 phatic acid. , ,, , 



One word or two more, and I shall have done. Mr. Wil- 

 liamson, who is a beginner in chemistry, will not, I am sure, 

 take it ill, if I, being his senior, take the liberty of advising 

 him to- be on future occasions a little more circumspect and 

 reserved before he broadly denies the correctness of state- 

 ments of others, — of statements which have been the result of 

 long, laborious, and I add, of conscientious researches ; of 

 statements, the truth or groundlessness of which can be so 

 easily ascertained if there is no disinclination to do so. 

 ■'■Basle, Aug. 20th, 1845. a, ,)i ^\th. u.juu 



" ^• '' , - — ' ' ■■ .'■ ' ■ '!'"^^;r. "fr-i:)f. i '.-^ ;TT?^-' 



f ^j ^IjXXIV. On Atomic Volume and Specific Gramty. 

 ~r^\By Lyon Playfair, Esq..i Ph.D. and J. P. Joule, Esq."^- 



Section I. 



'I'^HE discovery of Gay-Lussac, that gaseous bodies com- 

 -*• bine in equal or in multiple volumes, and that the result- 

 ing compounds stand in a similar simple relation to their con- 

 stituents, is one of the most important discoveries ever made 

 in physical science. Its utility has been diminished by its 

 supposed inapplicability to liquid and solid bodies, as its own 

 exactitude at different temperatures is entirely owing to the 

 equal expansibility of the same volumes of different gases by 

 ^qual increments of heat. mi\h 



In its most simple form, therefore, it was a priori iinpl*-0- 

 bable that the law of Gay-Lussac should apply to the liquid 

 and solid forms of matter. But, as the larger number of sub- 

 stances are either liquid or solid, and incapable of passing into 



* Communicated by the Chemical Society } having been read Mky 17, 



