The Microscope. A I 



GLASS DISSECTING DISHES. 



PROF CHAS. A. DAVIS. 



Noticing a note in regard to dissecting dishes or trays in a re- 

 cent nuraoer of The Microscope, I have thought that it might in- 

 terest some of the workers to know how I make a very serviceable 

 and cheap form. I bought some of the glass candy trays which 

 are used by grocers and others to display candy. Tlnese cost 

 about the same as tin dishes of the same size and are more dur- 

 able, let the light tlirough the sides and can be cleaned thor- 

 oughly. These can be bought of any grocer, and come in vari- 

 •ous sizes. Instead of cork for the bottom I use wax, a mixture 

 ■of paraffin and beeswax colored with lamp-black. I have never 

 tried either alone, but mixed them because I had both, and 

 thought the beeswax would toughen the paraffin, which it does 

 •admirably. In order to keep the wax from floating I put a layer 

 ■of No. 6 bird shot in the bottom of the dish and turn the hot 

 wax on to it, stiring it in order to cover the shot well and to. keep 

 the lamp-black from separating from the wax. The advantage 

 of wax over cork is great, I think, for it can be renewed when 

 'dirty or full of pinholes, by simply putting the dish on the top 

 of a steam radiator or a moderately warm stove for a short time, 

 •stiring the wax and allowing it to cool again. 



For finer or smaller work I use a glass sauce dish. 1 find 

 that common white porcelain butter-plates make very nice 

 " watch glasses," or rather a subtitute for them, as they furnish 

 a good ground on which to see specimens, particularly at night. 

 I use them almost exclusively and like them very much ; they 

 are also cheap. 



Apparatus for drawing minute OB.tECTs. — An ingenious de- 

 vice for drawing small objects was some time ago invented by 

 Fritsch of Vienna, and has been found of Valuable application 

 in the interests of naturalists. The instrument is intended to 

 throw an enlarged image of the object upon the table to admit 

 of its being copied. It consists of a Concave mirror of about 

 two and one-half inches in diameter, movably attached to the 

 summit of a metal or other kind of upright rod. Below it is a 

 movable stage to bear the object and with a central opening to 

 allow the passage of the light from the mirror. Beneath the 

 ?5tag€ is a movable rod bearing at its extremity a ring to receive 



