CONSTRUCTION OF THE MICROSCOPE. 



67 



Excellent Students' Microscopes are now produced by many other Makers; 

 among whom Messrs. Beck should be particularly mentioned, as having led the 

 way in supplying low-priced but really serviceable instruments, such as could at 

 that time only be obtained on the Continent. Their ' Economic ' Microscope 

 framed on the Continental model, and furnished with good Objectives of 1 inch 

 and l-4th inch, is sold for 5 Guineas; and other Objectives specially constructed 

 for it, ranging to the l-16th inch, with a complete set of Accessories, are supplied 

 at a very moderate cost. The same Makers supply an * Economic ' Wenham 

 Binocular, having two pairs of Eye-pieces, three Objectives, a glass rotating 

 Stage, and a jointed lengthening arm to the Mirror (which allows it to be used 

 above the Stage for the illumination of opaque objects) for 10 Guineas. Mr. 

 Collins also supplies a 10 guinea Wenham Binocular, with Objectives of 1 inch 

 and l-4th inch (80), the latter being specially adapted for use with the Binocular, 

 by a short mount which brings it close to the Wenham prism. Mr. Swift makes 



Baker's Student's Erecting Binocular. 



a 'College' Microscope, in which the Stage is fitted with a revolving diaphragm- 

 plate of ingenious construction, that brings its apertures up to the level of the 

 object-slide. Of Mr. Crouch's and Messrs. Parkes's Students' Microscopes also, 

 the Author can speak with approval, as regards both the mechanical and the 

 optical part of their work. 



65. Second- Class Microscopes. Under this head may be ranked those 

 instruments which combine first-rate workmanship with simplicity in the 

 plan of construction; and which may be consequently designated as ' Supe- 

 rior Students' Microscopes.' Among these the first place should be given 

 to Messrs. Powell and Lealand's Smaller Microscope (Fig. 48), which was 

 long the favorite instrument of British Histologists, and which, though 

 not adapted for objects requiring very oblique light, is still in demand 



