20 JAMES CLEUK MAXWELL 



then first in mathematics and in English, and nearly 

 first in Latia 



In 1847 ho was working at magnetism and tho 

 polarisation of light. Somo time in that year he was 

 taken by his uncle, Mr. John Cay, to see William 

 Xicol, tho inventor of the polarising prism, who 

 Uhowcd him the colours exhibited by polarised light 

 latter passing through unannealod glass. On his 

 return, he made a polariseopo with a glass reHeetor. 

 The framework of the first instrument was of card- 

 board, but a superior article was afterwards constructed 

 of wood. Small lenses mounted on cardboard wero 

 employed when a conical pencil w;us neoded. By 

 Leans of this instrument he examined the figures 

 ixhibited by pieces of unannealed glass, which ho 

 >repared himself; and, with a camera lucida and box 

 >f colours, he reproduced these figures on paper, 

 taking care to sketch no outlines, but to shade each 

 coloured band imperceptibly into the next, Somo of 

 these coloured drawings ho forwarded to Nicol, and 

 was more than repaid by the receipt shortly after- 

 wards of a pair of prisms prepared by Nicol himself. 

 These prisms were always \'cry highly prixed by 

 Maxwell. Once, when at Trinity, the little box 

 containing them was carried ofV by his bed-maker 

 during a vacation, and destined for destruction. Tho 

 bed-maker died beforo term commenced, and it was 

 only by diligent search among her effects that tho 

 prisms were recovered.* After this they were more 

 carefully guarded, and they are now, together with 

 the wooden polariscope, the bits of unannealed glass, 



* Professor Garnet! in Nature, November 13th, 1879. 



