108 CONSTRUCTION 



For those for 50 to 75 gallons, the best thickness is Y\ inch, and for 

 the still larger sizes up to 120 gallons, is }i inch. 



Cutting the Glass. A firm, flat surface, a good straight-edge, a sharp 

 wheel cutter and a steady hand are the essentials in this work. Bear 

 on the cutter firmly but not heavily. First experiment on a worthless 

 piece of glass. If the wheel does not make a continuous scratch, go over 

 the missed portion, but do not again pass wheel over former scratch, as 

 this ruins the wheel. When scratch is complete, break glass with thumbs 

 and fingers by bending upwards at one end of scratch. If glass does not 

 divide easily, tap the under side of scratch with solid part of cutter until 

 small splits occur along the line. It will then be safe to break. Large 

 plate glass is best broken by placing the scratch line over the straight 

 edge of a table and bearing down on glass. 



Setting the Glass. The edges of the glass should be carefully cleaned 

 with whiting, ammonia or alcohol to remove any grease. It is well to 

 first coat with gold size the edges which are to come into contact with the 

 cement, allowing this to set for a day or two. This is more particularly 

 needed with large plate-glass aquaria. Apply a liberal coating of aquarium 

 cement to the inside of frame, and a thin but well-covered coat to the 

 contact edges of the glass. Press into place slowly but firmly, cleaning 

 away at once all surplus cement. Light sticks cut of a length to brace 

 across inside of aquarium should be used to maintain an outward pressure 

 on the glass for several days until it is fairly set. After the glass is well 

 set, it is advisable, especially with the larger sizes, to run a line of 

 aquarium cement up the inside corners and along the bottom edges, cover- 

 ing with a narrow strip of glass, or, better, embedding a round glass rod 

 of from %- to f£-inch diameter in it, pressing in as far as possible and 

 wiping away the surplus cement. After about two weeks, fill slowly and 

 allow water to stand a week. Re-fill at least once again before introduc- 

 ing fishes. 



Stopping Leaks. Large aquaria nearly always leak a little at first, 

 or after moving them, or even after emptying without moving. This 

 usually corrects itself within a few days, but, as elsewhere directed, it 

 can nearly always be stopped by making the water very muddy. The 

 particles of dirt get into the leak and choke it up. This may require 

 several days. The water should be stirred occasionally. 



If an aquarium is quite old and fails to respond to the muddy water 

 treatment it should be thoroughly dried for not less than two weeks. 

 Tip the aquarium at a suitable angle and pour enough spar varnish 

 into each (inside) edge to saturate the cement and fill any cracks. Let 

 each edge stand until "set." Dry for a few days before re-filling. Re- 

 pairs on the outside are useless. 



