Mr. C. Tomlinson on the "inactive" Condition of Solids. 229 



ganic compound, including oxygen. The method for determin- 

 ing hydrogen and oxygen in an organic compound consists in 

 heating it to redness in a current of chlorine, when the oxygen 

 unites with the carbon in the substance, or that which has been 

 added to it, while the hydrogen combines with the chlorine to 

 form hydrochloric acid. The hydrogen is obtained by weighing 

 the latter, while the oxygen is found from the carbonic oxide 

 and carbonic acid formed. 



He also describes a method for determining carbon, chlorine, 

 bromine, iodine, sulphur, and nitrogen — a method for which 

 he claims far greater accuracy and ease of execution. The de- 

 terminations of chlorine, bromine, iodine, and sulphur are effected 

 by the new method simultaneously with the determination of 

 carbon and of nitrogen by a single analysis. 



The principle of the method consists in volatilizing the bodies 

 examined in a current of hydrogen, and burning the hydrogen 

 along with the substances volatilized in it in pure oxygen in a spe- 

 cial apparatus. The water formed is removed, and the other pro- 

 ducts (with the exception of nitrogen, which is determined by 

 volume) are collected separately in weighed apparatus. 



The author claims for his method, which he describes in detail, 

 the advantages of being easy, certain, and rapid, and having the 

 advantage over other methods of requiring little substance, and 

 of being free from the sources of error to which they are liable. 



XXX. On the so-called cc Inactive" Condition of Solids, 



Bij Charles Tomlinson, F.R.S. 



[Continued from p. 143.] 



SINCE the date of my paper on the above subject in the 

 Philosophical Magazine for this month, I have read some 

 remarks in the Comptes Rendus on M. Gernez's theory of the 

 disengagement of gases from their solutions, by those distin- 

 guished observers Messrs. Chevreul, Deville, and Matteucci. 

 They not only assent to this theory, but refer to various pheno- 

 mena on which, according to them, it throws light. M. Chevreul 

 remarked that a large number of experiments had led him to 

 admit the existence of a layer of air adhering to solid bodies ex- 

 posed to the atmosphere ; and he cites the experiment in which 

 gas-bubbles are disengaged from the surface of a solid, plunged 

 into a liquid, and exposed to an atmosphere that is being gradu- 

 ally rarefied by the air-pump. M. Deville considered the phe- 

 nomena to be further illustrations of the theory of dissociation. 

 Premising that I do not consider the phenomena in question 

 to fall under this beautiful theory, so far as T understand it, I 

 beg to submit to the above-named leading European savants my 

 theory, in a more precise form, and with some modifications. 



