514 



SUMMARY OF CURRENT RESEARCHES RELATING TO 



of the box. The lens may at any time be unscrewed and carried 

 in the pocket. The dissecting stage is a cork slide, plain on one side 

 for general work, but provided wifch a shallow cell on the other, for 



Fig. 116. 



the dissection of such objects as small glossy seeds which "fly" under 

 the needles. A pitted glass slide, to be used when the object is best 

 dissected under water, is also provided. 



Jaubert's Microscope. — Fig. 117 shows a Microscope of somewhat 

 unusual form, made by M. Jaubert of Paris as long ago as 1866. 



Besides the ordinary movement of inclination from the vertical to 

 the horizontal position, the stand is provided with a lateral inclining 

 movement at right angles to the former, by which the optical body 

 and stage can be completely inverted on an axis running through the 

 trunnion bar. M. Jaubert claims that this facility for inverting the 

 Microscope may be of use in chemical experiments. 



The attachment of the mirror can also be slid round the edge of 

 the stage from side to side, and sundry articulations give a great 

 range of motion to the mirror either above or below the stage. 



The fine adjustment is by means of a differential screw attached to 

 the nose-piece of the optical body. This system appears to have been 

 experimented with at various intervals since the days of Pritchard, 

 but has not met with permanent favour. In the ' Quarterly Journal 

 of Microscopical Science,' iv. (1856) p. 92, is a paper " On a New Form 

 of Microscope," by Mr. E. Warington, with a figure of the fine adjust- 

 ment, which was stated to be " constructed on the principle of a 

 common union-joint, the outer half of which works in a male screw at 

 the extremity of the body-tube, and acts against a spring in order to 



maintain a constant bearing " Mr. James Swift also some 



years ago devoted attention to working out a somewhat similar plan, 

 and in fact exhibited a Microscope embodying the fine adjustment at 

 the International Exhibition of 18i32. It may also be noted that a 

 Microscope of amateur construction (by Mr. W. A. Bevington) having 

 a fine adjustment of this kind at the nose-piece of the body-tube, has 

 been exhibited several times at the Society since 1875 when it was 

 made. 



The fine focussing by means of a difierential screw, together with 

 an analogous system for the coarse adjustment, and several other 

 curious mechanical movements as applied to Microscopes, &c., formed 



