_To make the frame._--If the aquarium is to be 10 x 8 x 5 inches, we shall need two pieces of glass for sides 10 x 5 inches, two for ends 8 x 10, and one for bottom 8 x 5; and two strips of tin 3/4 inch wide, 28 inches long, and four strips 10-3/8 inches long. These should be angled by the tinner, and out of them we shall make the frame. The 28-inch strips should be cut with tinner's snips half way in two at 10-3/8, 5-3/8, 10-3/8 and 5-3/8 inches, cutting off the end at the last mark. This keeps the top and the bottom of the frame each in one piece. Next we bend them into shape. When the corners are well squared they should be soldered. The four 10-3/8 pieces make the vertical corners and we will solder them in place. An easy way to be sure that each angle is square is to hold it in a mechanic's square while soldering it. [Illustration: _Figs. 58, 59. Permanent aquarium made of tin and glass._] _To set the glass._--Lay the aquarium cement (see recipe) on evenly all around the bottom of the frame and press the bottom glass into place. Put in the sides and ends in the same way. Next carefully put a few very limber twigs into the aquarium to hold the glass against the frame till the cement takes hold. Cut off the extra cement with a knife and smooth it nicely. Cover the frame with asphaltum varnish or black lacquer. In a week it will be ready to use. Double thick glass must be used for large aquaria. _Cement._--Shun all resinous cements that require to be put on hot. The following is a recipe for cement used in successful angle tin aquaria, for both salt and fresh water: 10 parts, by measure, fine, dry, white sand, 10 parts plaster of Paris, 10 parts litharge, 1 part powdered resin. Stir well together and, as wanted, mix to consistency of _stiff_ putty with _pure_ boiled linseed oil. The formula given by the U. S. Fish Commission is recommended: 8 parts putty, 1 part red lead, 1 part litharge. Mix, when wanted, to consistency of _stiff_ putty, with raw linseed oil. After reading all these directions and getting the idea of an aquarium, one should think the whole matter out for himself and make it just as he wants it. Directions are useful as suggestions only. The shallow form is better for raising toads, frogs and insect larvæ; the deeper aquaria show water plants and fishes to better advantage. INHABITANTS OF THE AQUARIUM. [Illustration: _Fig. 60. Eel-grass._]