THE SIMPLE MICROSCOPE 7 



Now, a dissecting microscope need not be ela- 

 borate or costly ; indeed, the student may extem- 

 porize one at any moment. All that is required is 

 a block of wood, say 6 inches square by an inch or an 

 inch and a half thick, for the foot ; a straight, stout 

 piece of wire about 6 or 8 inches long for the up- 

 right ; a cork ; and another piece of thumer but stiff 

 wire for the arm. The stout wire is to be fixed 

 firmly in the block of wood, so as to be perpendicular 

 to it. The wire for the arm is at one end bent at 

 a right angle ; the other end is twisted securely 

 round the cork. The bent end is shghtly sharpened 

 with a file, so that it may be inserted in a hole 

 bored through the handle of a pocket lens. A hole 

 must be bored through the centre of the cork, which 

 can now be made to shde up or down the upright 

 wire, in order that the lens, held by the arm parallel 

 to the foot-board, may be accurately fooussed. The 

 object, fixed on a piece of sheet cork pinned to the 

 wooden foot or otherwise secured, according to its 

 nature, can now be examined through the lens, and 

 the hands are free to use the dissecting tools, of 

 which more anon. If greater illumination of the 

 object is desired, hght from a lamp may be concen- 

 trated upon it by means of a buU's-eye condenser, 

 or be reflected upon it by a carefully arranged 

 mirror. 



An ingenious worker will easily improve upon a 

 dissecting microscope of such a rough-and-ready 

 order. For instance, it will be discovered that hght 

 transmitted through the object will prove advan- 

 tageous in some dissections. In Fig. 3 we have an 

 illustration of an excellent dissecting microscope 



