254 THE AMERICAN MONTHLY [Sep 



usual focussing substage. The top lens is also remova- 

 ble. The price of the optical part is only $13 ; of the 

 mount, with iris diaphragm and carrier for stop, $5 ; tha 

 stops and colored glasses in brass box, $3. Total, $21. 



New Catalogues. — We have received catalogues of mi- 

 croscopes and apparatus from Mr. J. H. Steward, of 406 

 and 407 Strand and 7 Grracechurch Street, and from 

 Messrs. A. Clarkson & Co., of Holborn Circus. The former 

 contains several microscopes of excellent design, aud a 

 full list of accessories, but is cumbered, as is too often 

 the case, with types of microscopes of antiquated patterns 

 long since superseded, which, we think, would be better 

 deleted, as they do not enhance the reputation of the 

 maker, and are likely to mislead beginners. Messrs. Clark- 

 son's catalogue is almost entirely devoted to second-hand 

 instruments, all offered at moderate prices, and nearly 

 all are of good and recent models. 



Formalin as a Preservative. — A 3 per cent solution 

 of formalin is preferable to spirits of wine for preserving 

 certain species of insects, as it does not affect the colors. 

 I find, however, that specimens so preserved and after- 

 wards dried deposit an oily dew, or in some cases crys- 

 tals, on the slide and cover-glass if mounted as dry ob- 

 jects for the microscope. Washing appears to have little 

 or no effect. Can anyone tell me how to obviate this with- 

 out discoloring the species ? — E. G. Wheler, Swansfield 

 House. Alnwick. 



Manchester Microscopical Society. — The transac- 

 tions for 1899 show that it is the most enterprising and 

 successful of any microscopical society in the provinces, 

 and well deserves its success. The membership during 

 the year appears to have been well maintained. The Coun- 

 cil speak of the attendance and the interest in the meet- 

 ings as being in every sense satisfactory. The Extension 

 Section appears to have delivered thirty-seven lectures in 

 the neighbourhood of Manchester during the winter : by 



