THE SIMPLE MICROSCOPE. 



63 



previously noticed, there are many very useful forms sold by 

 some of our other opticians in this metropolis, and in the 



Fig. 39. 



provinces ; those of Mr. Pritchard, which are described in his 

 works, require especial mention. The author of a little 

 tract, entitled The Wonders of the Microscope, recommends 

 strongly an instrument invented by Easpail, which can be 

 bought in Paris for thirty francs, or about twenty-five 

 shillings English : it is provided with four lenses, varying in 

 magnifying power from fifty to three hundred diameters. The 

 author was lately shown one of these instnunents, by his 

 friend, Mr. H. W. Diamond, and can speak very favourably 

 of its performance. 



As the single microscope is principally used for dis- 

 section, the most essential part, next to good glasses, is 



