1893.] MirROSf'OIUCAL .TOTRXAL. 221 



liand lens to the most coiM|>lex outfit for plioto-iuicro^iraphy 

 and conipk'te sets of aeliroiiiatic anil apoehrornatic objeetives. 

 In the way of stands there is nothinj,' specially new, which has 

 not been exhibited for several years, but there are some novel- 

 ties in accessories. One is a mechanical sta^'e, square in form, 

 attached to the main stem of the instrument and removed by 

 unscrewing a screw and raising a bar. It could be easily at- 

 tached to almost any instrument and ought to off'eragood hint 

 to American makers. The photo-micrographic apparatus is 

 very comj)lete, and has many peculiarities. The tube of the 

 microsco{)e is very wide (50 millimeters) and only three inches 

 long, but has of course a draw tube. The camera is designed to 

 be used with electric li<iht, and a beautilully designed lamj) for 

 the arc light is attached. The whole ajiparatus with achromatic 

 condenser, monochromatic light attachment, centering api)ara- 

 tus, stand, camera, etc., costs S500 in Germany or S7oO with 

 duty and freight paid. There are other interesting .sj)ecimens 

 in the exhibit, such as the micro-spectroscope, the micro-spec- 

 tral ])hotometer for quantitative micro-spectrum analysis, the 

 micro-sjiectral objective for observing and measuring the etiects 

 of the colors of the spectrum on microscopical objects, the spec- 

 tro-polarizer fordetermining the character of double refraction 

 in microscopical specimens for particular wave-lengths and the 

 refractometer for determining the refractive index of glass and 

 liquids. 



F. W. Schieck of Berlin, one of the oldest micro.scope makers 

 in Europe, makes a neat exhibit of cheap instruments, t'vo of 

 them being of an old pattern, rarely seen at present. One of 

 the?e is designed to have the specimens mounted on a large cir- 

 cular glass which are successively seen by revolving the glass. 

 This form is sometimes used for class demonstration. In the 

 other instrument, the objects are mounted in the rim of a brass 

 barrel, w'hich is turned around for each specimen to be sho«rn. 

 F. Leitz of Wetzlar, has a fair exhibit of his stands under the 

 charge of his American agents, Richards & Co. It is located 

 in the south end of the Mines and Mining Building, but the ex- 

 hibit is not in a place where it can be seen to advantage. He 

 has also a few instruments in the German Educational Exhibit, 

 where Hartnack of Potsdam, Siebert of Wetzlar, and a few other 

 minor makers are also represented. The only foreign makers 



