12 Professor Dewar on Liquid Atmospheric Air. [Jan. 20, 



bustion continued active, and for a time could be maintained in the 

 middle of the liquid oxygen. This result suggests that oxygen and 

 sulphur can enter into combination in a perfectly dry condition. 

 Some notion of the temperature of liquid air is given by running 

 on to the surface some absolute alcohol, which, after rolling about 

 in the spheroidal state, suddenly solidifies into a hard transparent ice, 

 which rattles on the sides of the vacuum test-tube like a marble. 

 On lifting the solid alcohol out by means of a looped wire the appli- 

 cation of the flame of a Bunsen burner will not ignite it. After a 

 time the solid melts and falls from the looped wire like a thick 

 syrup. 



It is not the question of the change of state in matter, however 

 interesting, that in our day has special attractions for the chemist, 

 but the means of studying the properties of matter generally under 

 the conditions of such exceptionally low temperatures as are the con- 

 comitants of the transition in the case of substances like oxygen and 

 nitrogen. The work of investigation in this field proceeds slowly but 

 surely, and one need not despair (unless on the grounds of expense) 

 in the future of adding further data to our knowledge of the pro- 

 perties of matter near the zero of absolute temperature. 



At the commencement of the lecture reference was made to the 

 dangers and difficulties of this kind of research, and it becomes a 

 pleasant duty to acknowledge the great services rendered by my 

 assistants. But for the persistency and determination of Mr. Lennox, 

 coupled with his marked engineering ability, the work would 

 not have made such progress, and he has been ably supported by 

 Mr. Heath. 



[J. D.] 



