MICROSCOPIC OBJECTS. 37 



be mounted when fresh and uninjured. The Oak Cur- 

 culio in many respects surpasses in brilliancy the Bra- 

 zilian Diamond Beetle. A magnifying power of 30 dia- 

 meters is amply sufficient. The light of an Argand 

 burner strongly condensed is essential to exhibit them 

 with effect. Mirrors are better than lenses for condens- 

 ing the light on these objects. 



Egg-shell. — If a small piece of egg-shell be ground 

 thin upon a hone, the inner side being left, the form of 

 the fibrin, on which the earthy matter of the shell is 

 deposited, may be readily observed. It resembles short 

 fibres matted together. It sometimes happens that eggs 

 are produced without the deposit of carbonate of lime ; 

 the envelope of these exhibits the fibrin to advantage. 



Eggs. — The eggs of birds are oval, but those of insects 

 assume a vast variety of forms ; some are furnished with 

 covers ; the surfaces of many are elegantly embossed and 

 fluted, whilst others, as those of the Bed Bug, have their 

 surface curiously granulated. Those given in the Cata- 

 logue win be found among the most interesting for the 

 microscope. They require in most cases to be viewed as 

 opaque objects under a power of 30 to 60 diameters. 



About seven years ago a gentleman in Norfolk dis- 

 covered, on a small piece of red sandstone, a few white 

 spots about the -joth of an inch in diameter". On examin- 

 ing these as opaque objects with a power of 30 diameters, 

 each appeared to have a white convex centre, with a 

 sculptured margin ; they were of a snow-white colour. 

 Since then they have been mentioned by various observers, 



