INTRODUCTION. 



XXX111 



examined a microscope which is manufactured at 

 that price by Messrs. Home, of Newgate-street, 

 which he calls the " medical microscope." The me- 

 chanical part is strong and steady, and the rack-work 

 excellent. It possesses a good achromatic object- 

 glass, which can be used of three powers, and is am- 

 ply sufficient to examine the structure of the potatoe, 

 the various fungi, and the form of the insect. When 

 circumstances will admit, he may extend the cost of 

 the apparatus to 100 guineas ; but the five guinea 

 instrument, except for very difficult cases of original 

 research, will answer all or most purposes. 



This instrument is 

 represented in the 

 engraving set up 

 ready for use ; and 

 consists of a firm 

 brass foot (A), into 

 which is screwed 

 the pillar (B), having 

 *at the upper part a 

 fine rack-work for 

 adjusting the focus. 

 At the top of the 

 .pillar is a brass arm 

 (C), holding the body 

 of the microscope 

 (D), consisting of a 

 brass tube, in the 

 upper part of which slides the eye-piece, so that it 



