THE GOLDFISH AND ITS CULTURE, 41 
even” in order to have a smooth bed for the glass. The 
upright pieces may also be fastened to the top and bottom 
frames without corner plates. In this case the uprights go 
inside of the upper and lower frames, being held in position 
by two small screws or rivets at each junction. (The water- 
proof cement used to set the lower ends of the glass must be 
mixed rather stiff in this case, in order to increase its resist- 
ance.) 
This frame is painted with one coat of red lead. After this 
is perfectly dry, a straight piece of one-quarter inch thick 
rough plate glass, such as is used for large skylights, is cut 
to fit loosely, leaving about one-eighth of an inch play all 
round, in the lower part of the frame. This glass is to be the 
bottom of the tank. It forms, so to speak, the foundation, and 
great care is therefore to be exercised in placing it properly. 
To this effect all of the entire lower angles are covered lib- 
erally with rather stiff aquarium cement (my water-proof cement 
is made for the purpose), being especially particular that the 
corners are well supplied with it. Now take a dry rag and 
wipe the corners of the glass plate perfectly clean and lay it 
gently and evenly on the cement bed. If the frame stands 
where it should, on a perfect level, the weight of the glass 
will tend to sink it into position; if, however, the cement is 
not very pliable, it will be necessary to assist by pressing it 
down with the hands; in this case the pressure should be 
gentle, uniform, and only in the middle of the plate. The sur- 
plus cement is now removed, both below and above, with a 
putty knife, followed by a dry rag. If examination shows that 
the cement has taken hold of the glass at every point, it is 
left to stand quiet for at least twenty-four hours. The two 
lights (technical terms for plates of glass), twenty-four by 
