156 The Microscope. 



WAYS • 

 AND PAEANS 



A MINIATURE TANK FOR MICROSCOPICAL PURPOSES. 



DR THOMAS S. STEVENS. 



Any collector from ponds and ditches, who has searched over 

 the contents of a round bottle with a lens, knows how difficult 

 it is to see and capture the interesting objects it may contain, on 

 account of the distortion produced by the convex sides of the 

 bottle. At a trifling cost a small flat aquarium, or large zoophyte 

 trough, may be made that will obviate this difficulty. 



Take two pieces of thin plate glass about six inches square, 

 and from a dealer in rubber goods obtain a strip of pure rubber 

 packing about f inch square, and so long that when bent into a 

 horse shoe or U shape, the ends will just come to the top edge 

 of the glass sides, while the curve shall not quite reach the bot- 

 tom. If the rubber is flush with the lower edge, or a trifle be- 

 low, the tank will not stand firm when finished. This rubber strip, 

 bent into proper form, is to be cemented between the two glass 

 sides. This may be easiest done by marking on a soft pine 

 board a square exactly the size of the glass, and on this square 

 bending the rubber strip into a U shape ; keep it in position by 

 placing pins or tacks, not through but at the sides of this pack- 

 ing, at various points, so as to hold it in shape. Smear tlie up- 

 per side of the packing thoroughly with cement, lay on one of 

 the glass sides, being careful to have it in position, press it firmly 

 -on the cement and place a weight above it to hold it down, and 

 leave it over night for the cement to harden. Smear the other 

 side of the rubber strip with cement and place the other glass 

 ripon it, being careful to have the edges of both sides parallel. 

 Weight it down, leave to harden as before, and the tank is done. 

 The cement that I have used is Van Stain's Stratena. No doubt 

 there are others that would answer the purpose as well. Marine 

 glue would probably be better. The rubber packing comes in 

 ■different sizes, from ^ to 1 1^ inch in thickness. The aquarium 

 may therefore be varied both in size and transverse depth to 

 fiuit the needs and taste of the maker. 



