770 SEC. 18. BIOLOGY. 



3572k. Holmes' divided Object Glass Binocular Mi- 

 croscope (the object glass being cut in halves and each half 

 forming one of the images). F. Crisp, Notting Hill. 



35721. Tolles' Binocular Eye-piece. 



F. Crisp, Notting Hill. 



3572m. Beck's Binocular Simple Microscope. 



F. Crisp, Notting Hill. 



3572n. Nachet's Triocular Microscope. 



F. Crisp, Notting Hill. 



3572o. Nachet's " Grand Microscope renverse avec 

 miroir argente " (giving very large magnification from the long 

 distance from object glass to ocular). F. Crisp, Notting Hill. 



3572p. Chevalier's Universal Microscope. 



F. Crisp, Notting Hill. 



3572q. Beale's Demonstrating Microscope. 



F. Crisp, Notting Hill. 



3572r. Brown's Pocket Microscope. 



F. Crisp, Notting Hill. 



3573. Microscope for Demonstration. 



Prof. Recklinghausen, Strassburg. 



The instrument is so made that it can be taken up in the hand like a 

 telescope, placed against the window, and the light found by even an un- 

 practised observer in a very short time. By using a condensing lens with 

 the instrument, ample illumination is obtained ; but faint daylight and even 

 lamplight will suffice. The instrument can be quite conveniently used with 

 a magnifying power of 400 diameters, especially as an arrangement (as in 

 Hartnack's immersion systems) is fitted to the lower end of the tube and 

 affords the most accurate adjustment. 



The object is to demonstrate microscopic preparations to a large audience. 

 This demonstration-microscope has this advantage over ordinary microscopes 

 for demonstrations, that it can be passed quickly round a class. As the 

 microscopic object under observation has to be vertical, it follows that the 

 preparation must be mounted and the cover glass fixed, and moreover it must 

 not float in a liquid. 



The tube with adjustment stand is made by Hartnack and Pratzmowski, 

 the apparatus for illumination and the table by Majer of Strassburg. 



3574. Microscope, with a set of objectives and eye-pieces, 

 containing 



a. Objective, No. 5, magnifies 184 to 506 times. 



b. No. 6, 220 612 



c. No. 8, 366 1,012 



d. No. 9, 458 1,266 



E. Winkel, Gottingen. 



