XXII 



arseniuretted hydrogen, chlorine, sulphurous acid had been liquefied before 

 his own experiments in 1823. He joined Mr. Brande in the delivery of the 

 morning course of chemical lectures at the Institution. In July he went 

 to the Isle of Wight with Mrs. Faraday, and returned again in August to 

 bring her home. He was elected an Honorary Member of the Cambrian 

 Society of Swansea, and a Fellow of the Geological Society. This year 

 the President and Council of the Royal Society appointed a committee for 

 the improvement of glass for optical purposes, consisting of Fellows of the 

 Royal Society and members of the then Board of Longitude. 



Mt. 33 (1825). 



Faraday was made Director of the Laboratory of the Royal Institution, 

 and therein he had three or four evening meetings of the members of the 

 Institution, from which came the Friday evening meetings of the members. 

 He was elected a Member of the Royal Institution, and a Corresponding 

 Member of the Society of Medical Chemists, Paris. He had a paper on 

 new compounds of carbon and hydrogen, and on certain other products 

 obtained during the decomposition of oil by heat, read to the Royal Society, 

 and printed in the Transactions ; one of these substances was benzol. He 

 had a paper in the Quarterly Journal on some cases of the formation of 

 ammonia, and on the means of testing the presence of minute portions of 

 nitrogen in certain states. 



In May a subcommittee, consisting of Mr. Herschel, Mr. Dollond, and 

 Mr. Faraday, was appointed to have the direct superintendence and per- 

 formance of experiments on the manufacture of optical glass. " It was my 

 business to investigate particularly the chemical part of the inquiry. Mr. 

 Dollond was to work and try the glass, and ascertain practically its good 

 or bad qualities, whilst Mr. Herschel was to examine its physical proper- 

 ties, reason respecting their influence and utility, and make his competent 

 mind bear upon every part of the inquiry. In March 1829 the committee 

 was reduced to two by the retirement of Mr. Herschel, who about that 

 period went to the Continent. ,, 



In July he left London by steamboat for Scotland. After visiting the 

 damask works, he went to Leith to see the glass works. He minutely de- 

 scribes the geology of Salisbury Craig, Arthur's Seat, and Craigleith 

 quarries, and then went to Rubislaw (Bleaching Liquor Works), Aberdeen. 

 Here he made many experiments for the proprietors, with whom he stayed. 



Mt. 34 (1826). 



He had a paper on the Mutual Action of Sulphuric Acid and Naphthaline 

 printed in the Philosophical Transactions, and another on the existence of 

 a limit to Vaporization, and in the Quarterly Journal of Science four papers — 

 on Pure Caoutchouc and the Substances by which it is accompanied in the 

 state of Sap or Juice, on the Fluidity of Sulphur at common temperatures, 

 on a peculiar perspective appearance of aerial light and shade, and on the 

 confinement of Dry Gases over Mercury. 



