1823.] ^ Mr, Rentes Experiments %vkh the Prism, H'S" 



Statement shoiving the Fall of Rain at Bombay in the last Sij; 

 Years, measured with Id oivarcrs Pluviometer, 



Article V. 



An Account of some Experiments with the Prism, 

 By S. L. Kent, Esq. MGS. 



(To the Editor of the Annals of Philosophy,) 



DEAR SIR, Carpenter's Hall, July 16, 1823. 



In offering to you the following details of a few simple expe- 

 riments with the prism, I am not impelled by the belief that they 

 may prove of any practical utility, or serve to throw any new 

 light on the doctrines relating to colours, to which I have given 

 little or no attention myself; they will, however, evince that this 

 instrument aifords the means of passing a few hoars very agree- 

 ably. Leaving to others more conversant with such pursuits to 

 look into them for any instruction they may possibly afford, I 

 cannot however refrain from noticing tne following experiment 

 made by Dr. Wollaston, Phil. Trans. 1802, vol. 92^ p. 2 :— 



" If a beam of dayhght be admitted into a dark room by a 

 crevice l-20th of an inch brostd, and received by the eye at the 

 distance of 10 or 12 feet, through a prism of flint glass, free 

 from veins, held near the eye, the beam is seen to be separated 

 into the four following colours only : red, yellowish-green, blue, 

 and violet." 



My seventh experiment, however, tends to the reduction of 

 the prismatic colours into three primary ones, wanting the blue 

 one observed by Dr. Wollaston. I beg to add that 1 am not 

 aware that any one of these seven experiments have hitherto 

 been made, or described by any other person, and am. Sir, 



Your humble servant, 



S.L.Kent. 



P. S. I should add that the prism used in these experiments 

 is five inches long, and the side planes one inch broad ; the lens 



