1 64 



PRACTICAL MICROSCOPY. 



2 inches deep, and is so constructed that, by using a divided 

 sliding lid (acting as a support for the dissecting stage), a 

 rest for the wrists is secured while the hands are employed 

 in dissecting. 



The duplex lens, giving three powers, 4, 6, and 10 dia- 

 meters, is screwed to the end of a brass focussing tube 

 moving upon a brass pillar attached to a sliding bar at the 

 bottom of the box. The lens may at any time be un- 

 screwed and carried in the pocket. 



FIG. 150. 



The dissecting stage is a cork slide, plain on one side for 

 general work, but provided with a shallow cell on the other, 

 for the dissection of such objects as small glossy seeds, which 

 " fly " under the needles. A pitted glass slide, to be used 

 when the object is best dissected under water, is also pro- 

 vided. A cutting needle, two dissecting needles, and a 

 pair of small forceps are also included, and the whole is 

 sold at the moderate price of 6s. 6d. 



Fig. 1 50 is a representation of Lawson's dissecting micro- 

 scope as made by Mr. Collins a very handy and compact 

 instrument, containing, as it does, in the unfolded case the 

 knives, needles, and scissors for the operator's immediate use. 



