How to Make an Incubator.

[From Scientific American Supplement.]

FIG. 1.—THE HOT-WATER INCUBATOR.
FIG. 2.—THE TANK. Observe that the tubes on the top and the spigot are quite long, in order that they may extend through the packing of sawdust which is to surround it. This tank is to have a close-fitting covering (top and sides) of wood, to resist pressure of water. The bottom is not to be covered.
FIG. 3.—DRAWER OPENING. Shows the thick packing, which is noticed at the opening. This extends all around. The front of the egg drawer (Fig. 4) fits in its place in order to complete the surrounding packing, when the incubator is closed, as at Fig. 1.
FIG. 4.—THE EGG DRAWER. The space just in front of the eggs is the portion partitioned off to fit in the opening at Fig. 3. The egg drawer is therefore LONGER than the tank and ventilator.
FIG. 5.—THE VENTILATOR. The tubes admit air from below, which passes into the egg drawer above through the muslin bottom of the egg drawer to the eggs. The eggs rest upon the muslin, which is tightly drawn over narrow slats running lengthwise the bottom of the drawer.
FIG. 6. Here we remove the front of the incubator in order to show the positions of the ventilator, egg drawer, and tank. First the ventilator, then the egg drawer (which of course should be longer than the others in order to fit in the opening shown at Fig. 3, but which we did not do here in order to mark the places), and on the top is the tank. When the front is completed the incubator is seen at Fig. 1.

Experiments with the incubator here given have been made all over the country. It is one that is in actual use, and has always given satisfaction. Having secured permission from the originator, we here illustrate it for the benefit of our readers.

To make this incubator get your tinner to make you a tank 15 inches wide, 30 inches long, and 12 inches deep, of galvanized iron or zinc, the iron being preferable. On the top should be a tube 1 inch in diameter and 8 inches high. In front should be another tube, 9 inches long, to which should be attached a spigot, as illustrated in Fig. 2. Having made your tank, have what is called the ventilator made, which is a box with a bottom but no top. The ventilator should be 8 inches deep, and 1 inch smaller all round than the tank, as the tank must rest on inch boards. In the ventilator should be four or six tin tubes  1/2 inch in diameter and 6 inches long. They should extend through the bottom, so as to admit air from below, and to within 2 inches of the top or a little less. Now make an egg drawer, which is a frame of wood 3 inches deep having no top or bottom, except that the front should be boxed off and filled with sawdust, which is covered over afterward with a piece of muslin to keep the sawdust from spilling. This box in front of the drawer exactly fits the opening in Fig. 3, when the drawer is in its place. Of course the egg drawer must be made longer than the tank and ventilator, in order to allow for this space which it fills in the opening, which is the packing all around the incubator. The bottom of the egg drawer should be made by nailing a few slats lengthwise to the under side, or rather, fitting them in nicely, and over the slats in the inside of the drawer a piece of thick, strong muslin should be tightly drawn. On this muslin the eggs are placed, in the same position as if laid in a hen’s nest, and it allows the air to pass through to the eggs for ventilation. The eggs can be turned by hand, marked for designation, or an egg turner may be made by fastening slats crosswise to one on each side running lengthwise, something like a window lattice, and when the eggs are placed between these slots by merely pushing the frame the eggs will turn over, exactly on the same principle that an egg will roll when it is pushed by a block, a book, or anything else; but we believe the method is patented, and do not advise infringement.

Having prepared the tank, let it be covered with a box, but the box must not have any bottom. This is to protect the tank against pressure of water on the sides, and to assist in retaining heat. Such being done, place your ventilator first, egg drawer next, and tank last. Now place a support under the tank and the box, or have them rest on rods, and as the weight of water will be great in the center, the iron rods should be placed crosswise under the tank every 6 inches. Now fasten the three apartments (ventilator, egg drawer, and tank) together, with boards nailed to the sides and back and front (of course leaving the opening for the egg drawer), care being taken to drive no nails in the egg drawer, as it must move in and out, and should have a strong strip to rest on for that purpose. Having completed these preparations make a larger box to go over all three, so that there will be a space on the sides, back, front, and on top; but as the ventilator must be filled with sawdust to within 1 inch of the top of the tubes, it serves for the bottom packing. Make the outer box so that there will be room for filling all around the inside box with sawdust, and also on top, being careful to let the tube for pouring in the water come through, as also the spigot in front. About 4 inches or so thickness of sawdust is sufficient, according to preference. The front of the incubator must be packed also, but an idea of how it should be done may be learned by observing the opening in Fig. 3, which is so constructed that the box in front of the egg drawer (Fig. 4) exactly fits into it, and completes the packing when the drawer is shut. The incubator should be raised from the floor about an inch, when completed, to allow the air to pass under and thence into the ventilator tubes.

The incubator being complete, the tank is filled with boiling water. It must remain untouched for twenty-four hours, as it requires time during which to heat completely through. As it will heat slowly, it will also cool slowly. Let it cool down to 120 deg., and then put in the eggs, or, what is better, run it without eggs for a day or two in order to learn it and notice its variation. When the eggs are put in, the drawer will cool down some. All that is required then is to add about a bucket or so of water once or twice a day, but be careful about endeavoring to get up heat suddenly, as the heat does not rise for five hours after the additional bucket of water is added. The tank radiates the heat down on the eggs, there being nothing between the iron bottom of the tank and the eggs, for the wood over and around the tank does not extend across the bottom of the tank. The cool air comes from below in the ventilator pipes, passing through the muslin bottom of the egg drawer to the eggs. The 15×30-inch tank incubator holds 100 eggs if turned by hand, but less if the eggs are placed between slats. Lay the eggs in the same [way] as in a nest—promiscuously.

DIRECTIONS.

Keep the heat inside the egg drawer as near 103 deg. as possible; the third week at 104 deg. Avoid opening the egg drawer frequently, as it allows too much escape of heat. Be sure your thermometer records correctly, as half the failures are due to incorrect thermometers, and not one in twenty is correct. Place the bulb of the thermometer even with the top of the eggs, that is, when the thermometer is lying down in the drawer. The upper end should be slightly raised, so as to allow the mercury to rise, but the bulb and eggs should be of the same heat, as the figures record the heat in the bulb and not in the tube. Keep a pie pan filled with water in the ventilator for moisture and keep two or three moist sponges in the egg drawer, displacing a few eggs for the purpose. Turn the eggs half way round twice a day at regular intervals. Let the eggs cool down for fifteen minutes once every day, but do not let them cool lower than 70 deg. No sprinkling is required if the sponges are kept moist. If the heat gets up to 110 deg. or as low as 60 deg. for a little while it is not necessarily fatal. Too much heat is more prevalent than too little. A week’s practice in operating the incubator will surprise one how simple the work is. The tank will be troublesome to fill at first, but the matter will be easy after it is done, as it can be kept hot. Heat the water in two or more boilers, as a large quantity will be required, and pour it in through the tube on top of the incubator boiling hot, using a funnel in the tube for the purpose. Just at the time of hatching out do not be tempted to frequently open the drawer. Cold draughts are fatal. Patience must be exercised.