Troughs

These should be made of seasoned timber, one and a half inches thick. They should be six inches deep and about fifteen inches wide, inside measurement. It would be better, perhaps, if the troughs were eight or nine inches deep, because then the water could be raised higher over the the young trout after they are hatched out. The difficulty in making them so deep is that when the sides of the trough are made so wide they are apt to warp or stretch apart at the top, and must be stayed in some way; for instance, by strips nailed across. But the cleaner the trough is of all strips, elbows or grooves the better. The troughs are divided into squares or nests by cross strips set on the bottom at intervals of eighteen inches. The reason for this division into nests and for these cross strips will be seen further on. These strips may be made of half-inch stuff and cut two inches in width. There is no necessity for nailing them to the bottom; fit them in accurately and set them edgeways at intervals of eighteen inches. As they do not need to be removed often, it is better to make them fit tightly. Other strips of the same stuff must be provided, to fit upon these and made wide enough to raise the water within an inch of the top of the trough, as these need to be often moved they must be made loose enough to take out, and yet fit accurately enough to raise the water over them when they are put in. A groove is sometimes made in which to run the strips, or shoulders nailed to the sides against which to set them, but it interferes with the equable flow of the water. New wood under the action of water develops a slimy sap, therefore it is necessary to paint the troughs with hot coal tar mixed with enough turpentine to thin it to about the consistency of paint. Glass has been used to cover them, and the wood has been charred to prevent the growth of fungus, but nothing answers so well as gas tar, which should be used to cover every thing in the troughs or ponds, and where fungus can do harm. The troughs should have an inclination of about one inch in eight feet - just enough to let the water ripple gently over the cross strips. They should not be longer than twenty feet, or the air in the water will be exhausted before the water reaches the end of the trough. There is more danger of this after the eggs are hatched out and the troughs are full of young fish. If possible the hatching house should be so far below the level of the spring from which its supply of water is derived, as to allow the troughs to be raised two or three feet from the floor. Where a large number of eggs are to be hatched, the inconvenience of stooping to care for them is very great.

Water Supply

From the filter the water runs into the distributing trough or pipe, which runs along the head of all the hatching troughs. The water may be let into the hatching troughs by faucets, or through holes cut into the trough. These holes should be covered with netting, or the young fish will run up out of the troughs into the filter, or coarse gravel may be heaped up at the head of the trough through which the water will run, but through which the young fish cannot work their way. The supply of water for one trough should be equal to that coming through a three-fourth-inch hole with three inches head; just enough to make a gentle ripple' over the cross-pieces. Be careful to get the troughs level cross ways, and the strips true, so that when the water is running it will form an equal current over every part of each strip along the whole length of the trough. If the water runs unevenly the eggs will be washed into a heap if they are being hatched on gravel, and many of them spoiled for lack of proper circulation of water around them. This supply of water will be sufficient until the eggs are hatched out, when a somewhat larger supply can be allowed. The water should be brought directly from the spring in a pipe of some kind, in order to preserve the proper temperature and keep the water as free from sediment as possible; and for the same reason the spring should be walled up to its smallest possible dimensions. If any surface water naturally runs into the spring, a ditch should be dug around the spring to lead it off. If the muddy surface water is suffered to run into the spring which supplies the troughs, the screen will very soon be choked up, and the sediment will find its way into the troughs in spite of all precautions and destroy the eggs.

Filter

The filter is a box six feet long by one and a halt feet wide and one and one-half feet deep; in which four or five flannel screens can be placed through which to filter the water before it passes into the troughs. The coarsest and cheapest red flannel is the best. It will rot and must be renewed once or twice in a season. Red flannel will last twice as long as any other. The flannel should be tacked on frames running in grooves set at an angle of forty-five degrees, (the top down stream) so as to expose as much surface as possible to the water. If the hatching house is small, the filter may be placed outside, but is better under cover. If the spring is well protected the screens will not need cleaning very frequently. They should be cleaned as soon as they look dirty, however often that may be, and can be cleaned best by being taken out and washed with a soft brush.

A filter can be made with sponges placed in a box with the water introduced at the top and brought out at the bottom, provided there is fall enough. The box should be about thirty inches long and twelve wide, and a board perforated with holes should be placed below the sponges, and leaving a space between them and the outlet pipe. This will answer on a moderate scale where only a small amount of water is used, and only a few hundred thousand fish hatched, and the sponges will remain clean for months. There should be an overflow pipe from the top to make sure that there is a sufficient supply of water and to carry off the surplus.

Sediment falling on the egg keeps the water off and destroys its life as effectually as being buried in the ground would destroy a man's life. If sediment falls upon the eggs it may be removed by gently agitating the eggs with a feather, or better still, by creating a current in the water with a leather, which current the eggs will follow, and as they roll over, the sediment will drop off. But the trout breeder has no business to be troubled in this way. If his apparatus is rightly constructed, and his filter properly attended to, there will not be sediment enough in the troughs to hurt the eggs, from the time they are put in until the fish are hatched out. The pipe which is let into the spring should have wire netting around it where the water comes in, to keep out impurities. This netting should be spread out so as to give a greater surface than the mouth of the pipe. If the netting covers only the mouth of the pipe, every speck of dirt which lodges on the netting diminishes by so much the supply of water; but if the surface of the netting is increased, much of it may be stopped up without lessening the supply of water. The best way is to make a box, say one foot square for each inch of diameter of the pipe, and run the pipe through a hole in the middle of the board, fitting it well; then fit a screen of netting on the front side in grooves so that it can be taken out and cleaned. This should be looked after occasionally, but if the spring is closely walled up, and the netting placed beneath the surface of the water, it will not probably need cleaning through the season.

Gravel For Troughs

The gravel for the troughs should be quite fine - about the size of peas. It is better to use wire screens as will be explained hereafter, but where only a few eggs are to be hatched and it is important to avoid expensive preparations, gravel will answer. It was formerly used altogether but is now almost wholly discarded. It is better to have it of a uniform size. Any kind of gravel is good which is free from iron rust, as that kills the fish. If the gravel is of some dark tint, the dead eggs, which turn milk white, will show very plainly upon it, and may easily be picked out. The gravel should be well washed before use, and we would even recommend boiling it, to destroy any eggs of insects which may be adhering to it. After the nests are prepared the gravel may be put in, one and one-half inches deep, which will bring it within one-half inch of the top of the cross-piece.

Implements

The implements of the fish-culturist are few and simple. A few feathers may be kept on hand to use in spreading the eggs when placing them in the troughs, in collecting them for packing, and moving them in the search after dead eggs. Several plans are in use for removing dead eggs from the trough. Some use a siphon to draw them up ; others bend wire into the shape of a small spoon, or bend an eye upon the wire just large enough to hold the egg. We recommend the use of nippers. These may be made of wire or some elastic wood like red cedar, bent or cut into the shape of the letter U, elongated to about six inches, and with loops of wire at the ends about the eighth of an inch wide. These will hold the egg without trouble. A small homoepathic phial is used to examine the eggs. The manner of its use is to fill it with water, put in the eggs to be examined, cork it, hold it up before the window in a horizontal position, and with your microscope look up through the side of the phial. This brings the egg which lies at the bottom of the glass within the focus of the microscope, and the water does not distort its shape. This seems to be a very simple thing, and hardly worth telling but of the hundreds who have tried to examine eggs in our hatching house, not a half dozen got it right until told how to do it. The microscope need not be very strong; one magnifying eight or ten diameters is amply sufficient. A small net will be of use in removing the young fish and any refuse in the water from the troughs; it should be about 6 inches in diameter, in the shape of the letter D, with the handle on the middle of the bend. It is very easily made by bending a wire in the desired shape, and twisting the two ends together for a handle. Thin gauze of some kind, like bobinet should be spread over the wire so tightly that the middle of the net shall hang only a half inch below the level. An iron spoon, well tinned or silvered, is used to remove the eggs. Some six-quart tin milk-pans will be necessary, for a variety of purposes. Eggs may be counted most easily by measuring them. For this purpose take any small glass, such as a very small tumbler, for instance, count out 500 or a 1,000 eggs, and with a file make a mark upon the glass as high as they reach, and the measure is always ready to your hand.

A watering pot with a fine rose spout is used to wash sediment from the eggs on the seives, and a broom of wig s is used to brush the screens of wire.