Water-beetles and water-spiders also thrive well, and their habits are most interesting to watch; but water-beetles fly by night, and unless you are careful to cover your tank you are likely to discover some morning that a number of your tenants have taken French leave.
You must be careful not to overstock your aquarium, for your fish will not thrive if they are overcrowded. Remember, also, that heat and dust are fatal to your pets. The water must be kept clean and cool at all times, and all foreign matter and every particle of decaying vegetation should be removed immediately.
To manage an aquarium successfully, no matter on how small a scale, requires a good deal of care and time, but you will find it time well spent, and the pleasure and knowledge the study of your pets will give you will be an ample return for the time you spend on them.
A Merry-go-round
A great deal of fun may be had with a merry-go-round in the rear yard, and while it may not be run by an engine or its motion accompanied by an organ, hand power will turn the table and music can be made with an old accordion or concertina. The only difficult thing about the whole affair is the bevelled gear, the shaft and crank; but if an old reaper can be found at a blacksmith-shop the difficulty is solved, for a pair of bevelled gears are on every reaping-machine. Of course a machine-shop or foundry would contain gearing of various sizes, and a five and twelve inch gear wheel will answer the purpose very well.
In the practical back-yard merry-go-round shown in Fig. 23 the revolving post is four inches square and may be of spruce or white-wood planed on all sides and provided with a ferrule at both ends. These may be taken from old buggy-wheels, and will prevent the wood from splitting when the pins are driven in. The lower cross-beams a a in Fig. 24 are of spruce, eight feet long and two by three inches. The beams b b are six feet and six inches long, and on these four the cross-plates are made fast that hold the top or deck planks. The six cross-timbers are of spruce, one by four inches, and are from two to eight feet in length, according to their location. The beam plan (Fig. 24) shows quite clearly how these supporting beams are arranged. They are held together with steel wire-nails driven down from the upper beams diagonally into the lower ones.
A MERRY-GO-ROUND
The longest beams are securely spiked to the revolving shaft, and in securing them in place take care to see that they are perfectly true, so that the outer edge of the platform will not dip and rise as it revolves. Drive a three-quarter-inch rod in the top of the shaft and another one in the bottom having a bevelled point as shown at Fig. 25. At the lower end of the shaft arrange the larger gear wheel and pin it fast so that it is fixed to the shaft and will not move.
An iron base-plate with an upright arm welded to it will hold the shaft and the smaller gear, which is to be arranged the right height to lock in with the teeth of the large gear. This plate is shown in Fig. 26; and through the four holes at the corners long screws are passed to bolt the plate securely to a wooden base, which last is set in the ground as shown at A in Fig. 27. The shaft B, to the end of which the small gear wheel is made fast, extends out beyond one of the upright posts, and at the outer end a crank and handle C are made fast, so that by hand-power the platform and shaft may be revolved.