224 THE MICROSCOPE. [November, 



EDITORS 



^^ DEPARTMENT 



QUERIES AND ANSWERS. 



Questions of all sorts relating to microscopy will be received by the publisher and re/erred 

 to Dr. S. G. Shanks, of Albany, N. Y.,wliose replies ivill be givenin this departvtent. Each 

 question is nuvibered for ftiture reference. 



95. What books give the distinguishing points of marine 

 and fresh-wafer diatoms^ and the forms comrnon to both? — F. 



W. Taylor. 

 Can any reader give the desired information? 



96. Do casts in Bright'' s disease polarize? 

 They do not polarize. 



97. Please explain iron-rust and oxidation. 



Ordinary iron-rast is a chemical compound of 2 parts of iron 

 and 3 parts of oxygen. Consult a chemistry for further informa- 

 tion. A clear description of oxidation would fill a page or two. 



98. Wotild the honey-bee and the bufnble-bee produce pre- 

 cisely si77iilar honey from si77iilar fowers ? 



Similar flowers produce similar nectar, but authorities differ as 

 to v/hether the nectar undergoes any alteration in the honey-crop 

 of the bee. The honey-bee, long and carefully bred, with a view 

 to improve quality and quantity, would probably store a better 

 honey from the same flower. 



99. Is the beetle the only insect " at home " iiz the air., upon 

 land., a77d i7i water? 



The beetle is probably the only insect sub-order so represented, 

 but no one species of beetle is equally at home in all those situa- 

 tions. The aquatic beetles fly in the air at night during the breed- 

 ing season, but they are practically helpless on dry land. They 

 find their food in the water, and the adult beetles must come to 

 the surface for the air they breathe. 



100. Is the Zoophyte trough 7iot practically convenient for 

 exa77iinatio7Z of urine? 



The Zoophyte trough is fragile, not easy to clean, and clumsy 

 for the above purpose. Use a plain slip, a small drop of urinary 

 sediment, and a large cover-glass ; if the cover slides about, use a 

 slip of blotting-paper to absorb the excess of fluid. The cover 

 will then remain in place in any position of the microscope stage. 



