Minutes of Proceedings. 313 



In 1845 tlift Government selected Dr. Andrews as the Yice-Presi- 

 dent and Professor of Chemistry in Queen's College, Belfast, in 

 consequence of which he gave up his medical practice. In the small 

 laboratory adjoining his lecture-room, with singularly simple appara- 

 tus and with comparatively little aid from any hand but his own, all 

 his original work was done. 



It will be observed, on examining the long list of his published 

 Papers, that nearly all his investigations belonged rather to the domain 

 of Physics than to that of Chemistry proper. They were far-reaching 

 in their scope, and of a character which required extreme nicety of 

 manipulation and the most careful j)recautions. One of these investi- 

 gations has been already alluded to. Of two others we shall speak 

 very briefly. 



In 1855 he communicated to the Eoyal Society the first of several 

 Papers on Ozone. Much discussion had arisen on the constitution of 

 this strange substance, and doubts had even been expressed whether 

 all the substances known as Ozone, prepared by different processes, 

 were really the same. By the series of experiments recounted in this 

 Paper he proves " that Ozone, from whatever source derived, is one 

 xmd the same body, having identical properties and the same constitu- 

 tion, and is not a compound body, but oxygen in an altered or allo- 

 tropic condition." 



His last work, however, was unquestionably his greatest, and has 

 been universally accepted as a discovery of the first importance, viz., 

 that on the connexion of the liquid and gaseous states of matter. It 

 formed the subject of the Bakerian lectures delivered by him in the 

 Royal Society, in the years 1869 and 1876. 



In these researches carbonic acid was the material experimented 

 upon, and he employed a beautiful apparatus designed by himself, and 

 executed under his own superintendence. This apparatus admitted of 

 the pressure and temperature being altered independently, while the 

 substance operated on was in glass tubes and completely under inspec- 

 tion. 



It had long been known that the liquefaction of carbonic acid and 

 other gases, by pressure, was greatly facilitated by reducing the tem- 

 perature ; but now Andrews, for the first time, proves that if the 

 temperature of the gas be above a certain point (for carbonic acid 

 31° C), no pressure, however great, will produce liquefaction: that 



