314 Royal Irish Academy. 



below this temperature liquefaction can always be effected by increased 

 pressure. 



He then points out how it follows as a necessary consequence that 

 the liquid and gaseous states are continuously connected — in other 

 words, that we can so alter by perfectly continuous changes the 

 temperature and volume of the carbonic acid that it shall be at the 

 commencement of the operation an undoubted gas, and at the close an 

 undoubted liquid; and that this can be done in such a way that 

 throughout the process the whole of the substance operated upon 

 shall be in but one physical state. The temperature referred to above 

 is thus seen to be one of the most essential elements, to be determined 

 for any substance, and Andrews gives it the name of the critical tem- 

 perature of the substance. His discoveries in this subject immediately 

 acted as a powerful stimulus on others to make further experiments, 

 and, as is well known, the last few years have been signalized by the 

 most striking achievements in the liquefaction of gases hitherto 

 supposed intractable. 



Dr. Andrews was elected a Fellow of the Royal Society in 1849, 

 and presided over the Glasgow meeting of the British Association in 

 1876. 



List of Papers by Dr. Andrews in the Transactions of the Academy : — 



" On the properties of Yoltaic Cii'cles, in wliicli Concentrated Sulphuric Acid 

 is the Liquid Conductor " (1838). 



" On the Heat developed during the combination of Acids and Bases" (1841). 



" On the Heat developed during the formation of the Metallic Compounds of 

 Chlorine, Bromine, and Iodine" (1842). 



The Eeport was adopted. 



The Secretary stated that the Address voted at the last Meeting of 

 the Academy to His Excellency the Lord Lieutenant had been pre- 

 sented by Dr. Ingram, v. p., and a Deputation, consisting of many 

 Members of the Academy. 



His Excellency delivered the following reply : — 



*' Me. President and Gentlemen, — 



" I receive with great pleasure the expressions of loyalty con- 

 tained in your address with reference to the Queen ; and I thank you 



