198 Lord Rayleigh, On a new form of gas battery. [March 6, 



There seems to be no doubt that the explanation is to be sought 

 within the domain of physiological optics. It has occurred to me 

 as possible that -with the large aperture of the pupil called into 

 play in a dark place, the focussing maybe very defective on account 

 of aberration. The illumination on the retina might then be realty 

 less in the image of a small than in the image of a large object of 

 equal ' apparent brightness.' 



(2) On a new form of gas battery. By Lord Kayleigh. 



In Grove's well-known gas battery it would seem that the only 

 efficient part of the platinum surface is where it meets both the 

 gas and the liquid, or at any rate meets the liquid and is very near 

 the gas. In order to render a larger area effective I have substi- 

 tuted for the usual platinum plates platinum gauze resting upon 

 the surface of the liquid in a large trough in such a manner that 

 the upper surface is damp but not immersed. One piece is ex- 

 posed to the oxygen of the air; the other forms the bottom of an 

 enclosed space into which hydrogen is caused to flow. The area of 

 each piece is about 20 square inches. 



To test the efficiency, the current was passed through an ex- 

 ternal resistance of about 6 Ohms, including a galvanometer. 

 Under these circumstances the permanent current was about one- 

 fourth of that obtained when a large Daniell cell was substituted 

 for the gas element. An inferior, but still considerable, current 

 was observed when coal gas was used instead of hydrogen prepared 

 from zinc. 



(3) Further observations on the transformation of alcohol and 

 on the formation of alcohol and urea in the living body. By P. W. 

 Latham, M.D., Downing Professor of Medicine, Physician to Ad- 

 denbrooke's Hospital. 



In a previous paper (Feb. 6, 1882) I endeavoured to show that 

 albumen is a compound of cyanhydrins, that these may be obtained 

 from the various alcohols and ketones, and be further transformed 

 into glycocine, leucine and other bodies which are derived from 

 the animal organism, and last of all I suggested as a reasonable 

 hypothesis that glycocine, leucine and other amido-bodies when 

 introduced into the living organism undergo a molecular trans- 

 formation into the metameric urethanes or alcoholic carbamates, 

 which are then decomposed in the recognised manner into urea 

 and the corresponding alcohol. 



