744 Prof. H. E. Armstrong on Low-Temperature Research 



ings ; both were noticed, however, in the " Illustrated London Xews."' 

 In those days one of the most interesting items to not a few readers 

 of this weekly journal was the column fairly regularly devoted to an 

 account of the lectures delivered at the Royal Institution ; these 

 were written by the then librarian Mr. Yincent. Unfortunately 

 science went out of fashion in the paper soon after this date. 



The Rev. John Barlow had lectured at the Institution, on March 

 14, 1856, on Deville's discoveries relating to aluminium; and 

 Faraday, on February 22, 1861, had dealt with his work on platinum. 

 Professor Dewar, in his lecture, illustrated Deville's method of pre- 

 paring aluminium from aluminium chloride by heating this with 

 sodium and so withdrawing the chlorine ; and spoke of his having- 

 produced both metals in large quantities. But in those days the 

 two substances were still chemical curiosities : now they are manu- 

 factured on a huge scale, with the aid of water-power, by electrolysis. 

 Sodium, it will be remembered, was one of Davy's greatest and most 

 fundamental discoveries ; and Faraday not only opened up the sub- 

 ject of electrolysis but is also to be counted as the father of the 

 dynamo now used in generating electric cttrrents. 



Deville's methods of preparing boron and silicon were also illus- 

 trated in the lecture, as well as the improvements he had effected in 

 the oxy-hydrogen blowpipe and in using this in melting platinum, 

 on the large scale, in conjunction with Messrs. Johnson and Matthey. 



Lastly, a fully illustrated demonstration was given of his Researches- 

 on Dissociation, to which, more than to any other part of his work,, 

 the great reputation of the French philosophical chemist is due. 



The lecture was clearly an act of piety on the part of Professor 

 Dewar, who may be reckoned as Deville's most devoted follower, the 

 French chemist's influence being clearly traceable almost everywhere 

 in his work. 



The account given of the following lecttire, in 1883, in the 

 " Illustrated London News," may be reproduced almost verbally as 

 showing how carefully the public were instructed by Mr. Yincent in 

 the past ; it is much to be wished that similar accounts could again 

 be published. Excepting the " Engineer " no paper is now at the 

 trouble to notice the lectures regularly. 



" The lecturer began by exhibiting a brilliant electric arc produced 

 by a new powerful gas engine and dynamo-electric machine. He 

 pointed out the distinction between the positive and negative poles 

 in the cliaracter of their light and their action upon the vapours of 

 copper and silver, the effect of the reversal of the current resembHng 

 those of the voltaic battery. The distinctive action of different 

 parts of the arc was shown by the spectroscope. The effect of the 

 different temperatures of gases upon the electric charge was illus- 

 trated. The brilliant lines in the spectrum of iron were obliterated 



