318 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 
ings on opposite sides—one at the bottom for admitting the water, which passes 
upward through the eggs and out through the second opening, which is situated at 
the top. Height, 12 inches; diameter, 8 inches. For economy of water, the outflow 
opening of one jar is connected with the inflow pipe of the next by means of rubber 
tubing. By this means the water passes through an entire series of jars before it 
finally escapes. The jar is used chiefly for hatching éggs of the Salmonide. It holds 
about 4,000 salmon eggs or 6,000 trout eggs. 
Invented by T. B. Ferguson, 1876. 
Atkins’s hatching-crate: 
A frame of metal and wood, with hinged cover, which incloses a nest of 9 egg- 
trays. Length, 12 inches; width, 12 inches; depth, 7 inches. This crate is used 
chiefly for hatching eggs of the Salmonidee. The trays are provided with corner 
strips of wood, which separate them slightly from each other to allow free circula- 
tion of water, though the spaces are not large enough to allow the escape of eggs. 
These crates can be placed either in the open stream or in ordinary troughs. 
Designed by Charles G. Atkins, Bucksport, Me.; presented by Mr. Atkins. 
McDonald hatching-jar, old style: 
Similar to improved jar now in use; but, instead of a metal cap, cork was used for 
the stopple. Invented in 1881; superseded in 1883 by ‘‘improved McDonald jar.”’ 
Chase hatching-jar: 
A cylindrical jar of glass, with a metal rim notched at one side and provided with 
a wire screen for retaining the fish. The water is introduced through a glass tube 
at the bottom and passes upward through the eggs. Height, 16 inches; diameter, 
6 inches. This jar is extensively used for hatching eggs of the white-fish. When 
the embryos are developing the outflow gate remains open, and through it any dead 
eggs are carried upward by the current and escape, thus preventing the injurious 
effects which arise trom fungus and dead eggs. 
Invented by Oren M. Chase, Detroit, Mich. 
Clark hatching-jar : 
A eylindrical jar of glass, with a metal rim, having a spout at one side, from which 
the surplus water escapes. The bottom of the jar is provided with a metal cone 
corresponding with the funnel-shaped end of the supply tube, which is prevented 
from coming in contact with it by means of slight projections on its inner surface. 
Height, 18 inches; diameter, 6 inches. This jar is coming into favor for hatching 
eggs of the white-fish, and is used extensively at the Northville hatchery. 
Designed by Frank N. Clark, Northville, Mich. 
McDonald white-fish jar: 
This is the same as the jar used for hatching shad, known as the McDonald uni- 
versal hatching-jar, with the exception that the closed top is removed and an open 
top with a tin funnel 33 inches long substituted in its place, through which the water 
escapes. The tube supplying the water is suspended from above to within one-eighth 
of an inch of the bottom of the jar, and is made of either glass, tin, or iron. 
McDonald's universal hatching-jar: 
A glass jar with metal cap, containing two circular openings. Through one of 
these, which is situated in the center, a glass tube for the introduction of water passes 
to within a short distance of the bottom of the jar. The other, situated near one 
side, contains a shorter glass tube, which serves as an outflow pipe. Height, 15 
inches; diameter, 6 inches; capacity, 5 quarts. Tle McDonald jar is successfully 
employed in the hatching of various species of heavy eggs. The water in entering 
is thrown against the bottom with considerable force, and is deflected upward around 
the sides of the jar. The eggs, which tend to settle to the bottom, are carried upward 
along the sides, thence inward toward the center, from which point they again sink 
to the bottom. The current is regulated to give the desired motion to the eggs. 
With heavy eggs like those of the salmon there is no motion, but the water coming 
from beneath tends to buoy the eggs upward, thus preventing any injurious pressure 
on the lower ones by the mass above. The outflow pipe is movable, and can be 
lowered to a point where the dead eggs, which are lighter than the good ones, come 
in contact with it and are carried off. By this means the eggs are kept compara- 
tively free from the injurious effects of fungus growth or decaying eggs. The jar 
can be filled two-thirds full of eggs with very satisfactory results, 75,000 shad eggs 
being considered a fair quantity. 
Patented by Marshall McDonald, Washington, D, C., in 1882, 
