442 Golden Wedding Presentation [June 17, 



spectroscopic researches which has made both their names so justly 

 famous. 



A few years later — in 1888 — he was appointed a member of the 

 Committee on Explosives, and with the late Sir Frederick Abel 

 invented the explosive cordite which the British army and navy have 

 used ever since, and which they used in the greatest war in history,, 

 and to which our victory in that war was largely due. 



But perhaps Sir James Dewar's greatest service has been the 

 preparation and handling of liquid air in large quantities, thus 

 making it available for experiment. For this purpose, in 1892 he 

 devised the vacuum-jacketed vessel, which was afterwards known as 

 the thermos flask, and has proved so very useful to all of us. Then 

 in 1898 came the further great step of obtaining liquid hydrogen in 

 large volumes. On one occasion 5 litres was carried from this Institu- 

 tion to the Royal Society at Burlington House. AVhat this meant 

 may be imagined if we bear in mind that the boiling point of 

 hydrogen is 422" below zero Fahrenheit. 



The result of these great researches has been an immense benefit, 

 as I say, to civilisation. Liquid oxygen is now a commercial article, 

 and to prove its value we have only to look at the attempt which is 

 now being made to ascend Mount Everest, an attempt which would 

 be absolutely impossible if it were not for that invention. If that 

 attempt succeeds it will be due, not only to the skill, experience and 

 intrepidity of the explorers, but to the inventive genius of Sir James 

 Dewar. 



But perhaps his labours can best be judged by my giving you a 

 few figures. In the course of the last forty-four years he has 

 delivered more than fifty Friday evening discourses ; he has de- 

 livered more than thirty sets of lectures covering the whole range 

 of chemistry and chemico-physics ; he has delivered nine sets of 

 Christmas lectures to juveniles, and has thus firmly established in 

 the minds of the rising generation a foundation of scientific study. 



I am sure you will agree that he has not only very worthily 

 maintained the traditions of this Institution, but has enhanced them 

 and has followed worthily in the footsteps of those great men that 

 we all honour so much — Davy, Young. Faraday, and a host of others. 

 It is all very well for Englishmen to praise our great scientists, but 

 when praise comes from foreigners it is doubly valuable, and I should 

 like to read what Dr. George E. Hale of America has said about 

 Sir James Dewar, because it puts in the smallest possible compass 

 and in the neatest possible way what I would like to say myself, but 

 can never hope to express so happily. In a letter received two 

 months ago, Dr. Hale, who is Director of the Mount Wilson 

 Solar Observatory, says : " For many years I have been an ardent 

 admirer of the Royal Institution, to which I return on every possible 

 occasion. In some mysterious way, which the conservators of other 

 scientific establishments might envy, the managers and the pro- 



