184: 



THE MICROSCOPE. 



[August. 



holds the lever arm A tightly against the screw-arm F. The 

 slightest motion, therefore, of the screw F is communicated through 

 the lever A and the rod C to the body of the microscope. 



The great delicacy of this arrangement will be appreciated when 

 it is noticed that the distance from III is double the distance IB, 

 therefore any motion at B is only half that at H. This adjust- 

 ment is one of the most delicate made for use with high powers. 



Gum for Slide Lrabels. — Dissolve 2 grams of aluminum 

 sulphate in 20 of water. Mix the solution with 250 grams of 

 strong mucilage (2 of acacia gum to 5 of water). The alumi- 

 num sulphate greatly increases the adherent properties of the 

 gum. 



PVBLI CATIONS 



Life-history of the Vermillion-spotted Newt. By Prof. S. H. 



Gage. Ithaca, N. Y. 



This is a reprint from the American iV«/?/;'«//^/ of December. 

 Prof. Gage is not only a naturalist and a microscopist, but an 

 artist, as appears in the brilliantly-colored frontispiece. A bibli- 

 ography contains full records of the literature of the subject, while 

 the text would seem to leave little more to be said on the subject. 



Die Botanische Mikrotechnik. By Dr. A. Zimmermann. 

 Tubingen, 1892, pp. 27S. 



This is a handbook of microscopical technique especially as 

 related to botanical w^ork. It is illustrated with 63 engravings in 

 the text and accompanied by a copious bibliography and index. 

 Being in German it is not available to American workers in 

 general, but some of our advanced manipulators who read Ger- 

 man will find it useful. The price is 6 marks. Order it from 

 H. Laupp'schen Buchhandlung in Tubingen or from F. A. 

 Brockhaus in Leipzig. 



