1900] MICROSCOPICAL JOURNAL. • 81 



or separated by sliding the tubes. For the purpose in- 

 tended, the magnifying power necessary is only 10 to 15 

 diameters. Besides servingfor^watching insects moving 

 on the ground, the instrument, it is stated, is admirably 

 adapted for use as a field glass. 



Standards. — Microscopists. both at home and abroad, 

 will hail with satisfaction the resolutions that have re- 

 cently been adopted by the Council of the Royal Micro- 

 scopical Society to standardize the various parts of the 

 microscope and its accessories. A beginning has already 

 been made, for the details of which we are indebted to 

 the courtesy of the Council. The standards adopted in 

 1882 have been withdrawn, and the size for the inside di- 

 ameter of the sub-stage fitting has been fixed at 1*527 

 inches (38-786mm). The gauges for standardizing eye- 

 pieces will, in future, be the internal diameter of the 

 draw-tubes ; the tightness of the fit being left to the dis- 

 cretion of the manufacturers. Four sizes of the internal 

 diameters of the draw-tubes have been fixed as follows : 

 No. 1, 9-173 inch (23-300 mm.). This is the Continental 

 gauge. No. 2, 1-04 inches (26-416 mm.), is the mean of 

 the sizes used by the English trade for students and small 

 microscopes. No. 3, 1-27 inches (32-258 mm.), is the 

 mean of the sizes used for medium-sized binoculars and 

 other microscopes of a similar class. No. 4, 1-41 inches 

 (35*814 mm.), is the maximum size for long-tube binocu- 

 lars. The sub-stage gauge is that which has been used 

 by the English trade for many years past, the variation 

 among different makers being not more than a few thous- 

 andths of an inch. We hope to be able shortly to give 

 the standard gauges of the eye-piece cap and of other 

 apparatus. The plugs and ring gauges of all of the above 

 may be inspected by the public at the Society's rooms. 



Fungi. — : With all the diversity of interesting lines of 

 research that are offered to the student of botany to-day, 



