26 Chemical Notices : — M. Soret on the Density of Ozone. 



independent of i for other surfaces besides the sphere, impossible 

 though it be to see through the labyrinth of such a function. 

 (In the paper dated March 23, the quantities cf> Y . . . are all func- 

 tions of i } and it is only the «th that is equal to zero.) 



J. H. Pratt. 



Calcutta, May 18, 1867. 



IV. Chemical Notices from Foreign Journals. 

 By E. Atkinson, Ph.D., F.C.S. 



[Continued from vol. xxxiii. p. 454.] 



M SORET, as the result of some experiments on ozone*, 

 * assigned to this substance a density once and a half 

 that of oxygen. He has endeavouredf to control this result 

 by a determination based on the unequal diffusion of gases of 

 different densities. 



Imagine two vessels superposed, separated by a diaphragm 

 perforated by a hole which can be opened or closed at pleasure, 

 and suppose at starting that the lower vessel contains a definite 

 mixture of oxygen and chlorine, while the upper one contains pure 

 oxygen. If communication be established, some of the chlorine 

 will diffuse through, and after a certain time its quantity may be 

 determined. If now the experiment is made with a mixture of 

 oxvgen and ozone in the same proportions, a certain quantity of 

 ozone will diffuse into the upper vessel ; if this quantity be less 

 than the quantity of chlorine, it may be concluded that the ozone 

 is less dense. If the duration of the experiment were very short, 

 the quantities diffused would be inversely as the square roots of 

 the densities of these gases. 



The construction of an apparatus for this experiment presents 

 several difficulties, owing to the circumstance that neither mer- 

 cury nor water among liquids, nor any organic substances or me- 

 tals among solids, could be used. 



For diffusion-vessels, two large glass tubes about 45 millims. 

 internal diameter were used, the ends of which were closed by 

 glass plates. Their capacity was about 250 cubic, centims. 

 The glass plates were long and rectangular in shape, and perfo- 

 rated by a hole of suitable size and dimensions. The ends of 

 the apparatus could thus be closed ; or by sliding the plate so 

 that the hole coincided with the interior of the vessel the closing 

 was only partial, and by these holes gas could be allowed either 



* Phil. Mag. S. 4. vol. xxxi. p. 82. 

 t Comptes Rendus, May 6, 1867. 



