CHAPTER OF VARIETIES. 



to examine it, when he discovered the mischief to arise from blood 

 worms boring therein. Now as I know that this gentleman is not 

 an entomologist, I suspected that he was mistaken in the identity 

 of the species, for I cannot see what purpose worms of this nature could 

 have in perforating so hard a substance ; and I therefore think it not 

 improbable that, if worms were indeed the real cause, they were of some 

 other species : but I should be inclined to think that instead of worms 

 the real offenders were some animals of similar economy to the Teredines, 

 Lithophagd; and Lithodomi, molluscous animals which excavate gal- 

 leries in Avood and hard solid rocks. SOLITABIUS. 

 May, 1833. 



ON THE RELATIVE WARMTH OF COLOURS. As many occurrences 

 of Nature are only explicable upon the principles of caloric, it is very 

 necessary that the naturalist should be acquainted with them, and 

 therefore the following few lines upon the subject cannot be considered 

 as entirely unconnected with his pursuits. In most works upon caloric 

 the method given for ascertaining the relative warmth of different 

 coloured skins, leaves, &c., (but more frequently cloth) is by laying 

 them side by side upon a smooth and level bed of snow when the sun 

 shines thereon, when the result will be, that the colour which imbibes 

 the most warmth from the sun's rays will sink deep in the snow, while 

 the rest will sink in depth in proportion to the degree of warmth which 

 they contain. Now this plan of experimenting can only be tried in 

 winter when the snow lies upon the ground, but my plan, which is very 

 simple, can be tried in summer. Take as many burning glasses of the 

 same power, as you have objects to experiment upon, and fix them up- 

 right side by side before the sun, and having fastened your objects in a 

 row upon a board, bring them to the exact distance of the foci of the lenses, 

 so that the concentrated rays of the sun may fall upon them, and then 

 by means of a watch held in the hand, the variation of time required to 

 consume the one before the other can be ascertained with exactness. The 

 colour of that one which consumes first will be the warmest, whilst the 

 others will consume according to their relative degrees of warmth. 



SOLITARIUS. 



London, May, 1833. 



ON THE REDBREAST BUILDING WITH OAK-LEAVES. The notion 



which your correspondent entertains of the materials employed by birds 

 jii the construction of their nests differing according to the localities in 



