In the four corners of the white-wood board cut a hole with bit and chisel three-quarters of an inch square as shown at Fig. 16. Saw the bottom of each square stick so as to cut away about a quarter of an inch of wood on each side as shown at the lower part of A in Fig. 15. This is made so that the uprights will fit snugly into the holes and the shoulder formed by the saw-cuts will rest on the top of the base board.
With straight rule and pencil mark parallel lines connecting each hole as shown at D D in Fig. 16. These lines should correspond in position with the grooves cut in the posts; then remove the posts and with grooving-plane or chisel and mallet cut the grooves about three-eighths of an inch in depth. The glass sides fit into these grooves, and the top rails made from the long stick cap the upper edges of the glass sides. The ends should be lapped and screwed down to the top of the corner-posts to bind the glass and wood-work in one compact framework.
Before any of the wood-work is put together give it three successive thin coats of black asphaltum varnish, which can be purchased at a paint or hardware store. Each hole and the plug ends of the corner-posts are to be coated with thick asphaltum varnish, and when wet with the varnish the posts are to be driven into the holes. Screws passed in through the sides of the base board will hold them securely in place.
From a glazier or hardware store purchase two panes of double-thick glass ten by fourteen inches, and two measuring ten by twenty-two inches. Give the grooves a thick coat of the asphaltum varnish, slide the glass down into the grooves, and screw the top rails in place. When the glass is in place and before the top rails are put on, the glass should stand a quarter of an inch above the top of the corner-posts. When the rails are laid in place the top edge of the glass should be caught by the groove in the rails, otherwise the glass, having no support at the top, would bow out on account of the pressure of water, and either cause the glass to break or the joints to leak. Press the glass sides against the outer edges of the grooves and lightly insert some wooden wedges into the grooves to hold the glass in place temporarily for a day or two or until the varnish sets. Then fill the open spaces in the grooves with a putty made from whiting and asphaltum varnish. This you will have to make yourself with a putty-knife on a plate of glass, marble, or slate, for you cannot purchase it. Common putty is not hard enough and will not dry for months, while the special putty will set quickly and dry hard in a few days. When all the work is completed about the aquarium allow it to stand for at least a week, in which time the putty and varnish will harden.