216 IDEAL HOME LIFE
and temperature does not especially affect the aeration of the well-balanced aquarium.
The Aquarium Tank
Undoubtedly the best kind of a receptacle for the beginner is the oblong, straight-sided aquarium with metal frame, glass sides, and slate or soap-stone bottom. The medium sizes holding from eight to ten gallons, up to twenty gallons, will be the best for the beginner. The smaller sizes are more difficult to balance and the larger ones are more expensive. For aquaria holding ten gallons and upward, the only type that can be used to advantage is that with metal frame.
When well set up such a tank will last for years without leaking, and is easily reset, or can often be readily mended by running a little asphaltum, red lead, or an aquarium cement in the joints.
The rectangular, straight-sided, all-glass jars, holding up to eight or ten gallons, are excellent; better in some respects than those with metal frames, for they are not likely to spring a leak. The glass jars, however, are more likely to crack and so prove an extra expense, but in the hands of the experienced aquarist they are perhaps the most satisfactory kind for sizes under five gallons. Care should be taken to see that such jars rest firmly and evenly upon their bases, and that they are not subject to sudden changes of temperature. It is well to place an asbestos mat, or a pad composed of a few layers of blotting paper, under the jar to act as a shock absorber and to distribute the weight more evenly.
The cylindrical jar with straight vertical sides is satisfactory to maintain, but the inmates appear somewhat distorted through the curved sides. For smaller aquaria the ordinary battery jar is as good as anything, except for the distortion, and has the advantage of being cheap. Very beautiful and well-balanced aquaria can often be made with the two-quart size, but these are suitable only for very small animals and few of them.
On no account should the ordinary globe be used. This is