70(J 



APPENDIX. 



Fig. 427. 



and yet very efficient working ones, with objectives as high as 

 ith, the price of which does not exceed $75.^ 



Mr. Jas. W. Queen, of Philadelphia, has prepared one of the 

 most convenient and portable microscopes for the use of students 

 that has been made. It is all contained in a mahogany box, six 

 inches square and eleven inches high, with' a small drawer within 

 for objects, forceps, &c. The stand is of cast iron, with two up- 

 rights supporting the stage and body of the instrument; between 

 the uprights is an axis upon which the whole upper part of the 

 instrument turns, enabling it to take a horizontal or vertical 

 position, or any intermediate angle most convenient for observa- 

 tion. The movable part, consisting of the stage, the body, and 

 bar containing the adjustment, is fixed to the axis, on which it 

 readily turns. There is an inner tube for increasing power by 

 extending the distance between the eye and object-glass. "Within 

 the quadrangular bar, to the top of which is attached the body of 

 the instrument, is the fine adjustment for foci ; the milled head on 

 the top of the bar operates upon the spring within, and carries the 

 body and object-glass from, or to, the object being observed, with 



the greatest facility. The 

 stage upon which objects are 

 placed to be viewed is made 

 double, the upper portion be- 

 ing movable by a small lever 

 which produces rectilinear or 

 eccentric motion, thus giving 

 greatfacilitiesto the microsco- 

 pist for viewing any portion 

 of the object he may desire; 

 the slide containing the ob- 

 ject is kept in place by two 

 spring clips attached to the 

 stage ; the under portion of the 

 stage carries a revolving plate 

 to which the polarizing prism 

 is attached when in use; a 

 diaphragm with various aper- 

 tures is beneath the stage; 

 the mirror is made to slide 

 up and down on the tube 

 that supports it, and can be turned to any angle for light that 

 may be desired; a condensing lens for opaque objects, mounted 

 with a jointed arm, is attached to the collar through which the 

 body passes. Two eye-pieces and two object-glasses are fur- 

 nished with the instrument, also the polarizing prisms. The 

 lowest power is about 50 diameters, and that can be increased to 

 400 or 500. A drawing-prism can also be furnished when de- 

 sired. (Fig. 427. ) 

 Messrs. J. &'W". Grtjnow, of New Haven, Connecticut, havein- 



' See Hassall's Microscopic Anatomy, editeil by H. Vanarsdale, M.D. 



J. W. Queen's Microscope. 



