42 THE GOLDFISH AND ITS CULTURE, 
fifteen, that are to form the front and rear are now prepared. 
These are best of one-quarter inch new plate glass, or they 
may* be cut out of second-hand polished plate glass (pieces of 
broken show-windows), or where this cannot be had, they 
should be of extra heavy double thick French or so-called 
English twenty-six ounce glass. In every case the lights 
should be as straight and clear as they can be had. Should 
one or the other be slightly bent, the bent (convex side) should 
go towards the outside of the tank. These also, like the bot- 
tom, should fit loosely into the frame, and if one of the long 
edges should be rough or ragged, this should go up in order 
to have the lower edge fit snugly against the bottom. (Fig. d). 
The lights are now cleaned with water and wiped perfectly dry. 
The angles on the bottom and those at the uprights, but not 
the upper horizontal ones, are next filled with cement, as was 
done when the bottom glass was placed, and the lights are 
then set in place, using gentle force to make a uniform fit. 
Two wooden sticks (braces) are then placed across from one 
to the other to hold them in position. Now the surplus cement 
is removed and the glass again wiped clean. 
Our next move is to measure the distance between the 
two lights just set, as the two end lights should fit snugly, 
but without any strain, against them. Double thick French 
glass is best suited for these; the edges that will meet the 
other glass should be clean cut. We then proceed to set 
them as described above for the others. 
It is unnecessary to use waterproof cement on the upper 
ends of the glass, as these, not coming in contact with the 
water, need not be watertight. Common putty will answer 
here if it is desirable, for appearance sake, to imbed the glass 
at these points. For practical purposes it is not necessary to 
