286 The Microscope. 



useful in gouty and rheumatic cases. This great warmth of the 

 byssus, hke the similar quality in silk, results probably from both 

 being imperfect conductors of heat as well as of electricity. 



' It is not probable that this material will ever be obtained in 

 much abundance, or that it will cease to be a rarity, except in the 

 places of its production. It is never seen in England save in the 

 cabinets of the curious. 



' The appearance and general characteristics of the produce of 

 the pinna, the spider, and the silkworm, are so similar, as to have 

 acquired for them one generic name. If all their constituent 

 parts be alike, it forms another among the numerous subjects for 

 surprise and admiration, excited by contemplating the wonderful 

 works of nature, that the same silky principle can be alike elab- 

 orated from the fish, the fly, and the mulberry leaf.' 



THE MICROSCOPE. 



NO. III. 

 ACTIVE MOLECULES, CONTINUED. 



BuTTEUFLiES AND MoTHs. We cannot enumerate all the 

 different sorts of these beautiful insects, and it is impossible to 

 describe the variety and splendor of their plumages, surpassing all 

 the magnificence of the richest and most costly dress. All the 

 butterfly and moth tribes are bred from caterpillars. The num- 

 ber of these insects is very great ; LinnEeus reckoned eight or nine 

 hundred different kinds, some of which are extremely rare, and 

 only found in particular places. The legs, antennae, the eyes, in 

 fact every part, when examined, afford the highest entertainment. 



Dust of the Feathers of a Butterfly's Wing. The 

 wings in themselves are, like the common fly's, transparent, but 

 owe their opacity to the beautiful minute feathers which cover 

 them ; and, examined by the microscope, nothing can exceed 

 the beautiful and regular arrangement of these little substances, 

 which, by their different colors, serve to paint the wing, and by 

 their regular layers, resembles the tiles of a house-top. Careful- 

 ly brush some of the dust off" on your slide, between two pieces 

 of laic, place it under the microscope, and you will be richly re- 

 warded for the trouble taken. With a high power and strong light, 

 beautiful prismatic colors and lines may be discovered. 



