THE AMERICAN 



MONTHLY 



MICROSCOPICAL JOURNAL. 



Vol. XI. FEBRUARY, 1890. No. 2. 



All comviufitcations for this Journal, whether relating to business or to editorial 

 matters, and all books, pamplilcts, exchanges, etc., should be addressed to Ameri- 

 can Monthly Microscopical Journal, Box 6jo, Washington, D. C. 



Europeajt subscriptions may be sent directly to the above address accompanied 

 by International Postal Order for $1.13 per annum, or they may be sent to Messrs. 

 Trilbner &^ Co., S7 Ludgate Hill, Londoti, or to Mr. W. P. Collins, ij/ Great 

 Portland street, Londo)i, accompanied by the yearly price of five shilli^igs. 



Some Recent Microscopical Apparatus. 



By BAUSCH & LOME, 



ROCHESTER, N. Y. 



In the microscope shown in the frontispiece, the construction of the 

 Continental model developed by Hartnack, and now generally adopted 

 by Leitz, Zeiss, and others, has been followed. There are embodied 

 in it some improvements which have been considered important. 



It is made of brass throughout, highly polished and lacquered. The 

 base is of large dimensions, and, therefore, more firm, particularly when 

 the body is inclined. The stage also is of large dimensions, thus allow- 

 ing the use of culture slides without the danger of tilting. A groove is 

 provided on its lower surface for the slide with cylinder diaphragms. 

 This slide may be replaced by another, carrying a standard size sub- 

 stage, arranged to be centered, and provided with revolving diaphragm. 

 To this may also be fitted any of the regular substage accessories. The 

 main tube is provided with a draw-tube sliding in a special sheath, and 

 when extended gives a total tube length of 170.0 millimeters. The bio- 

 logical series of objectives, especially computed for this instrument, are 

 corrected for this tube length, and the medium and high power should 

 be used with no other. In case it is desired to use the English standard 

 tube length and Bausch & Lomb's regular objectives, the tubes may be 

 extended by unscrewing the sheath and removing the screw-stop. The 

 fine adjustment is by micrometer screw, and works on the triangular 

 bearing of the arm. 



The instrument is made in two forms : with solid pillar and arm, and 

 with joint for inclination. These instruments are supplied with Conti- 

 nental eye-pieces, which, with the objectives | and /, , give a magnify- 

 ing power from 45 to 485 diameters. 



Condenser Mounting. — In the frontispiece is also shown a con- 

 denser mounting with iris diaphragm. This mounting provides a move- 

 ment for the diajDhragm by rack and pinion. It has in addition a recess 



Copyright, 1890, by C. W. Smiley. 



