912 SEC. 18. BIOLOGY. 



3572m. Beck's Binocular Simple Microscope. 



F. Crisp. 



3572n. Nachet's Triocular Microscope. F. Crisp. 



3572o. Bracket's " Grand Microscope renverse avec 

 miroir argente " (giving very large magnification from the long 

 distance from object glass to ocular). F. Crisp. 



357 2p. Chevalier's Universal Microscope. F. Crisp. 

 3572q. Beale's Demonstrating Microscope. F. Crisp. 

 3572r. Brown's Pocket Microscope. F. Crisp. 



3573. Microscope for Demonstration. 



Prof. Recklinghausen, Strassbarg. 



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 conveniently used with a 

 magnifying pOAver 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 eyepieces, 

 consisting of 



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 



R. Winkel, Gottingen. 



3575. Microscope constructed specially for the examination 

 of microscopic sections. R. JFuess, Berlin . 



3576. Immersion Lens, with special contrivance for in- 

 creasing the magnifying power from 300 to 1 >000 times with the 

 low eyepiece. R> Winkel, Gottingen. 



3577. Microscope (small model), commonly used. 



Dr. Hartnack, Potsdam. 



3578. Small Microscope, specially suited for mineralogical 

 researches. Dr. Hartnack) Potsdam. 





