ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 



01 



pillar under the stage pulled out and clamped, the tuhe drawn out to 

 graduation 17, aud the jointed mirror arm arranged. The coarse adjust- 

 ment is by rack-and-pinion, and the fine by micrometer screw. The 

 movement and the illumination are of such a nature that oil-immersions 

 can be used and the instrument applied to bacteriology. 



Seibert's New Dissection Microscope. — The foot and object-stage 

 of this instrument are both of large size, the latter being 10 by 10 cm. 

 The adjustment is by means of rackwork. The lens-carrier is movable, 

 as is also the mirror. The support for the operator's arms can be dis- 

 connected and removed. The instrument can be fitted with a drawing 

 apparatus (fig. 22), formed of a pillar erected on the horseshoe foot, and 



Fig. 22. 



carrying a jointed arm with a camera lucida. A suitable loup and con- 

 cave leuses are also supplied for drawing larger objects slightly magnified 

 or minified. 



Seibert's Large Model Microscope, No. 3. — This instrument is 

 chiefly distinguished from the No. 2 stand by somewhat smaller dimen- 

 sions, and is remarkable for its low price. It corresponds to the Zeiss 

 ii A. It has a horse-shoe foot and no clamp for inclination. 



Seibert's Laboratory Microscope. — This instrument is remarkable 

 for its low price. As will be seen from fig. 23, the construction is of 

 the simplest character. The body is focussed by rack-and-pinion, aud 

 the careful workmanship of the arrangement renders the instrument 

 available for use with high-power objectives. The stage is of large size 

 (100 by 120 mm.). The movable mirror is plane and concave. The 

 makers recommend it fur the detection of trichinae and as a very useful 

 laboratory adjunct. 



