92 Dr Stark on the Influence of Colour on Odours. 



1. The next set of experiments were intended to ascertain 

 the comparative attraction of animal and vegetable substances. 

 The first of these was upon equal weights of black wool and 

 black silk, ten grains of each exposed to the vapour of camphor 

 in the manner already stated. The black wool gained 1 /^ grains, 

 the black silk 1^^ grains. From this experiment, it would ap- 

 pear, that of these two animal substances, silk possesses the 

 greater attraction for odours. 



2. In equal weights of white wool and white cotton, the cotton 

 gained ,-« of a grain ; the wool ^^. 



3. In another experiment with white silk, white wool, and 

 white cotton, ten grains of each, the result was, 



Silk had gained 3/g grains in weight. 

 Wool .... 2/g 

 Cotton .... 2^% 



4. In a similar experiment, with the usual weights of the 

 same articles, 



Silk had gained I y*o grains in weight. 

 Wool . . . . T o <jf a grain. 

 Cotton . . . . j% 



5. Another experiment, in which black silk, black wool, and 

 black cotton, were exposed in equal quantities of the usual 

 weight to the vapour of camphor, as before described, gave this 



result. 



Black silk gained j2_ of a grain. 



Black wool • • I'o 



Black cotton . . ^'^ 



6. In an experiment with white silk, white wool, white cottmi, 

 and white card, each weighing ten grains, and exhibited as be- 

 fore, the following were the results : 



White silk had gained 1 /jj grains in weight. 



White wool ... 1 ,^'5 



White cotton ... 1 



White card ... jS of a grain 



These last experiments tend to shew, that different substances 

 attract odours in different proportions, and this independent 



