at the Royal Institution, 1908-1916 761 



influence through the walls of a quartz vacuum vessel but even when 

 solid oxygen surrounded by liquid hydrogen is subjected to their 

 impact. 



In the Friday evening lecture on January 20, 1911, on " Chemical 

 and Physical Change at Low Temperatures," the production of ozone 

 by the impact of ultra-violet rays on solid oxygen at the temperature 

 of boiling hydrogen was rightly referred to as " perhaps the most 

 remarkable of all low-temperature reactions observed." 



The solidification of oxygen was first demonstrated, on this 

 occasion. The main subject of the lecture, however, was the remark- 

 able gas, carbon monosulphide, CS, discovered as the outcome of 

 experiments made in conjunction with the late Dr. H. 0. Jones. 



The " Heat Problems," brought under consideration in the Friday 

 evening on January 19, 1912, were, as usual, cold problems. On this 

 occasion a very remarkable demonstration was given of the persistence 

 of drops of liquid hydrogen falling a considerable distance through 

 the air. 



Owing to Sir James De war's state of health he did -not lecture 

 in 1913. 



In 1914, on January 23, the discourse delivered was on " The 

 Coming of Age of the Vacuum Flask ;" but the real subject was an 

 account of a detailed inquiry into the specific heat of the elements 

 between the boiling-point of liquid nitrogen and hydrogen, by means 

 of an improved form of liquid-hydrogen-calorimeter. The amount 

 of hydrogen present in the atmosphere and respired air was also 

 brought under notice. 



On January 22, 1915, this last subject was still further developed. 

 The preferential condensation of gases by charcoal was next dis- 

 cussed ; then illustrations were given of the diffusion of hydrogen 

 through heated platinum and of helium and neon through quartz. 

 The method followed in an inquiry into diffusion through india- 

 rubber was also referred to. 



SuEFACE Tension Phenomena. 



Thus far, since 1883, low-temperature research had occupied Sir 

 James Dewar's attention almost exclusively. But the beginning of a 

 new septennate has been marked by his entry upon a new line of 

 inquiry. Having done his best, in the past, to still intermolecular 

 forces, he has now passed to the study of their freest interplay in 

 A¥ater-soap films. His ingenuity and dexterity of hand have never 



