sxviii President's Address for the year 1878. 



gases and vapours. The collation of Davy's remarks 

 appended to Faraday's paper on the liquefaction of chlorine 

 (as already given) with Pictet's method and his theoretical 

 views, is certainly a matter of interest, but as Mr. Barton 

 during the evening will explain the details of M. Pictet's 

 experiments, and as time presses, I need say no more on this 

 highly interesting subject. One word, however, may be 

 added concerning the converse problem of the liquefaction 

 and vaporisation of refractory solids. Carbon uncombined 

 is known only in the solid state ; to melt and vaporise it is 

 a work yet to be accomplished, but with the results recently 

 achieved we are encouraged to hope for further triumphs, 

 and the ultimate confirmation by actual experiment of all 

 that has been premised on theoretical or mathematical 

 grounds concerning the several states of matter ; or should 

 we fail in this, we may yet hope for experimental proof of 

 what is defective in the hypothesis, by means comparable to 

 those by which the almost tenable phlogistic hypothesis of 

 Stahl was overturned on the application of the deep-search- 

 ing experimental method of Lavoisier. 



