106 Dr. Woods on the Relative Amounts of Heat produced by 



from the truth ; and it is impossible to regard them without 

 feeling how purely the act of absorption is a molecular act, and 

 that when a liquid is a powerful absorber the vapour of that 

 liquid is sure also to be a powerful absorber. 



To experiment with water, it was necessary to saturate it with 

 the salt of which the cell was formed, but the absorptive energy 

 is due solely to the water. We might infer from this alone, were 

 no experiments made on the aqueous vapour of the atmosphere, 

 that that vapour must exert a powerful action upon terrestrial 

 radiation. In fact, in all the statements that I have hitherto 

 made I have underrated its action. 



The deportment of the elements sulphur and iodine, dissolved 

 in bisulphide of carbon, is in striking harmony with all that we 

 have hitherto discovered regarding the action of elementary 

 bodies. The saturation of the bisulphide by sulphur scarcely 

 affects the transmission, while a quantity of iodine sufficient to 

 convert the liquid from one of perfect transparency to one of 

 almost perfect opacity to light, produces a diminution of only 

 two per cent, of the radiation. This shows that the heat really 

 used in these experiments consists almost wholly of the obscure 

 rays of the lamp. It is worth remarking that the obscure rays 

 of a luminous source have a much greater power of penetration 

 in the case of the liquids here examined than the rays from an 

 obscure source, however close to incandescence. The deport- 

 ment of bromine is also very instructive. The liquid is very 

 dense, and so opake as to cut off the luminous rays of the lamp ; 

 still it transmits 77 per cent, of the total radiation. It stands in 

 point of diathermancy above every compoundyiquid in the list, 

 except bisulphide of carbon. This latter substance is the rock- 

 salt of liquids. 



Before a strict comparison can be made between vapours and 

 liquids, they must be examined by heat of the same quality, and 

 I have already made arrangements with which I hope to obtain 

 more complete and accurate results than those above recorded. 



XI. On the relative Amounts of Heat produced by the Chemical 

 Combination of Ordinary and Ozonized Oxygen. By Thomas 

 Woods, M.D* 



THE difference between the physical conditions of ordinary 

 oxygen and oxygen in its more active state, or ozone, does 

 not seem to be known. Clausius considers the atoms of the 

 former to be grouped in a binary arrangement, and those of the 

 latter to be either isolated, or so joined to the molecules of ordi- 



* Communicated by the Author. 



