COLLINS'S STUDENT'S. 97 



in polished mahogany cabinet complete (fig. 51): an ex- 

 ceedingly cheap instrument. 



Fig. 51. Collins' c Student's Binocular Microscope. 



Collinses Lawson Binocular Dissecting Microscope. 

 This instrument is intended to supply a want, often felt 

 in anatomical and botanical investigations, when only a 

 moderate magnifying power is required. 



In consequence of using both eyes it can be worked with 

 for a length of time with great comfort. A large range of 

 field is obtained, and plenty of room for working. It 

 consists of a neat oblong French-polished mahogany box, 

 measuring, when closed, 6J in. by 4 in., fig. 52. The top 

 and front let down by hinges, and on the inside of them 

 are fitted the scissors, needles, and knives necessary for 

 dissecting. The two sides draw out about six inches, 

 and are hollowed out so as to serve as rests for the hands. 

 The magnification is obtained by two lenses mounted in 

 the eye-pieces, as represented in the diagram, and may be 

 adjusted to the focus by a sliding bar. These show the 

 object beautifully in relief. Beneath is a gutta-percha 

 trough or stage, to pin the object down to, which can be 



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