00^ CHAPTER OF VARIETIES. 



I should not like to risk a fine or rare specimen, such as the diadem 

 spider, (A. diadema) or brown water spider (A. aquatica), on the 

 efficacy of either method. If any of your readers would answer this as 

 to the best manner of " setting " them, many scarce specimens would 

 no doubt be saved. 



B. B. CORNEY. 



London, July, 1833. 



ON THE COLOURS EXHIBITED BY THE CHAMELEON. It frequently 



occurs that an individual can suggest to others a clue to the solution 

 of a mystery, although he himself is unable to prosecute "his own views. 

 In the present case, this is my situation; I state that which I conceive 

 to be very probable, but yet not possessing one of the animals to which 

 it relates, I am unable to pursue the inquiry which, I strongly con- 

 ceive would, in the end, answer my expectations. The sudden varia- 

 tion of colour exhibited by the chameleon, has, since that period in 

 which it was first observed, been regarded as a wonderful phenomenon, 

 and has employed numerous naturalists and philosophers in attempting 

 to explain it, and, as yet, they have not succeeded. The light, which 

 I conceive I am throwing upon the subject, embraces optical principles, 

 while it discards the belief of the variation in colour being voluntary, 

 or under controul of the animal itself. Some years since, I saw the 

 chameleons in the Tower of London, and it was then I first noticed 

 the similarity of shape, existing between the three-sided form of its 

 body, and that of a prism ; and the idea immediately presented itself, 

 to my mind, that this was probably the principal cause of its possessing 

 the extraordinary power of reflecting all the prismatic colours like that 

 instrument ; for although the fluids of its body may be rather opaque, 

 yet they may be sufficiently adapted to reflect various colours when 

 the light falls upon it. But, whatever may hereafter be discovered to 

 be the cause, I premise that the peculiar shape of its body will be one, 

 if not the principal explanatory point of it. If, however, my idea 

 should in the end prove nothing more than fanciful, the singular coin- 

 cidence of the shape of the body so strongly, although somewhat 

 irregularly, resembling an optical instrument, possessing similar quali- 

 ties, will, I trust, be considered sufficient to warrant me in having 

 entertained it ; and the publishing it under the belief that it mav afford 

 to others, who may have opportunities of experimenting upon the 

 animal, a clue to the discovery, will, I hope, secure me from the 

 attacks of those who may differ in opinion. SOLITARIUS. 



