896 



SUMMARY OF CURRENT RESEARCHES RELATING TO 



necessary, and the top lens may be taken off when a less convergent 

 cone of light is required for low-power work." 



Chevalier's Microscopes. — The Microscope figured at p. 699 (fig. 

 125) should, we understand, have been described as by the firm of 

 Chevalier, who have no connection with that of Chevallier, the con- 

 structors of the instrument fig. 122. 



Swift and Son's Pocket Microscope. — Messrs. Swift and Son have 

 added a stand to their (Brown's) Pocket Microscope (figs. 158 and 

 159), which is one of the smallest Microscopes made having any 

 pretensions to be a serviceable instrument and not a mere toy. As 

 now modified, it appears to be the most complete really " Pocket " 

 instrument yet issued. It is furnished with 1 in., l-4th, and l-8th in. 

 dry objectives, and 1-1 6th in. immersion, three eye-pieces, achromatic 



Fig. 158. 



condenser with rotating disk having three diaphragms, central stop, 

 and radial slots, together with polarizer, analyser, adjustable concave 

 mirror in gimbal fitting, the whole (with glass slips) packing in a 

 mahogany box 4^ X 3| X l^- 



The standard consists of a conical pillar, to the lower end of 

 which three rods are screwed radially, having milled heads at the 

 outer ends and forming a tripod foot; the upper end has a cradle- 

 joint carrying a dovetail slide-socket, in which fits a corresponding 

 slide at the back of the body-tube. The Microscope can be inclined 

 on the cradle-joint as required. The slides, which can be of the usual 



