336 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
cold floor all day in a chilly, drafty room, at work requiring deftness of touch and 
close attention, considerable endurance is needed physically, and it is by no means 
unusual at hatcheries to have to call in new help while the regular hatching-house 
force are suffering from colds, rheumatic attacks, etc. In a dry, well-lighted hatchery 
the interest of the fish-culturist does not wane from physical causes, and the eggs and 
fry consequently receive the benefit of these comforting features. Nearly anyone 
will hurry through with his allotted number of baskets in a sloppy, cheerless, and 
chilly barn, slighting the work in spite of himself, and yet the same person would 
almost always give intelligent attention to a task which he finds extremely interesting 
under physically comfortable conditions. 
Besides the superintendent the permanent force of the station numbers 6, 
including a cook. All the regular work of fish-culture is done by this force, and a 
large part of the building and permanent improvements is executed by the same 
persons. When additional labor is necessary a request is made upon the superin- 
tendent of the association’s canneries at Karluk Spit. 
A furnace in the basement of the main building, directly under the hatching- 
house, heats the water for a system of piping used solely for artificial heating. A 
set of coils is arranged directly under each section of troughs, and there is also a 
system of piping on the bottom of the reservoir pond. When artificial heat is 
employed in forcing the hatching of the eggs the steam boiler is placed in use to 
drive the pumps. The latter draw the water from the reservoir pond, where it has 
been warmed, discharging it into the filter upstairs. It will be remembered that the 
waste of the hatching-house troughs escapes to the reservoir pond, but before using 
this warm water again filtering and aerating are necessary. Just enough new water 
is added to freshen the supply without much reducing the temperature, and very 
little is needed. If the water were not used over and over again in this manner it 
would be almost impossible and entirely impracticable to heat it sufficiently during 
the cold winter months, but the system of aerating and freshening is so well con- 
trolled that the feed water remains perfectly good after repeated use. 
The feed water of the hatching-house, whether received from the flume or pipe 
line, is thoroughly filtered before passing into the troughs. Much of the coarser 
debris, such as straws, twigs, leaves, etc., is cleared from the water at the settling- 
pond and tank-house, and coarse-mesh wire screens in the lower end of the flume are 
also employed. Referring to the sketch it will be seen that the filter is simply a set 
of screens of varying degrees of fineness, arranged in a long wooden trough. The 
water falls from the flume or pipe upon the upper end of the top screen, which is a 
long board pierced with numerous auger holes. These holes increase in diameter as 
the farther end is approached, and the board is given sufficient pitch to cause the water 
to run down and cover it all, the function of the board being primarily to distribute 
and incidentally to aerate. 
Falling next through a fine-mesh screen of wire netting the water is received 
in very fine spray-like condition by the last and lowest tra}^ or screen. This is made 
of burlap, tightly stretched over a strong, light wooden frame, and has proven a 
most excellent filtering material. After it has become thoroughly soaked the jute 
or hemp of which it is composed swells closely and tightly, efficient^ cleansing the 
