Chemistry and Physics. 145 



mixture contained 54-8 volumes of chlorine, 42'3 volumes of 

 hydrogen and 2*6 volumes of air, the union was complete after 

 an exposure of 31 hours to the albo-carbon light; while if the 

 gases were mixed in equal volumes 250 or more hours were re- 

 quired under similar conditions. If the hydrogen be in excess 

 the effect is similar though less strongly marked. 



Berthelot expresses the opinion that it is necessary to take 

 into the account in all experiments made on the combination of 

 mixed gases, the possible reactions which may take place between 

 the gases themselves or the products of their reaction, and the 

 walls of the containing vessel. This action in some cases may be 

 simultaneous and not successive, chemical stresses between the 

 gases and the material of the walls, which together constitute a 

 heterogeneous system, determining the occurrence of any change 

 at all. This local action on the walls will occasion local thermal 

 disturbances which may alter the nature or the rate of the change 

 at the point, and which may even lower the initial temperature at 

 which these changes will take place. Moreover, the reaction may 

 be influenced by the condensation of a gas film on the surface of 

 the walls of the tubes. In fact, the action of surfaces more than 

 the action of masses is here to be taken into the account, these 

 surface actions determining the equilibrium of the system. 



Gautier, in reply, calls attention to the fact, that Berthelot's 

 criticisms refer rather to his early experiments on the combination 

 of heated gases than to the action of light on gases, now under dis- 

 cussion. The function performed by the walls of the vessel, 

 which in his investigations were kept constant in temperature 

 and were not permitted to become heated by the reaction, is, as 

 he believes, to regulate the speed of the combination and not to 

 limit it. Again, carbon monoxide and oxygen show similar phe- 

 nomena, to those given by hydrogen and oxygen ; but in the for- 

 mer case there can be no hydrate formed. The same results are 

 obtained with vessels of glass, silvered glass, porcelain or quartz, 

 and they are independent of the mode of cleaning the surfaces to 

 which the gas is exposed. — C. B., cxxiv, 1267-1273; 1273-1276; 

 1276-1278, June, 1897. g. f. b. 



3. On the Series Spectra of Oxygen, Sulphur and Selenium. — 

 In continuing their researches, Runge and Paschen have now 

 examined the oxygen compound line spectrum and have given in 

 tabular form the wave-lengths of the observed lines. Besides 

 the six triplets which were noticed by Piazzi-Smyth, the authors 

 have found seven other triplets in the spectrum, similar in charac- 

 ter, the whole thirteen taken together forming two distinct series. 

 As far as can be determined, the differences between the rates of 

 vibration of the three component lines of each triplet, are the 

 same. All the triplets are distributed regularly over the spec- 

 trum, the two series which they form being similar to those which 

 have been already observed in the case of magnesium, calcium, 

 strontium, zinc, cadmium and mercury. Moreover, there are in the 

 oxygen spectrum two other series of lines in addition to the triple 



Am. Jour. Scl— Fourth Series, Vol. V, No. 26.— February, 1898. 

 10 



