554 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [2] 
be placed in each box to obtain the best possible results. A description 
of the “Clark” hatching-box is given in Report of United States Com- 
missioner of Fish and Fisheries for 1872~’73, pages 583 and 584. 
The hatchery is located at the foot of a gentle slope of land, and 
ascending this declivity about 200 feet we find issuing forth within a 
circle of a hundred feet numberless little springs which furnish in the 
aggregrate about 175 gallons of water per minute. <A public highway 
running directly in front of the hatchery and between it and the spring, 
by intercepting the flow of water from the latter, serves incidentally as 
a dam, thereby creating a pond having an area of one-eighth acre, aver- 
aging 4 feet in depth and extending back.a few feet beyond the spring 
area, thus incorporating the whole of the latter. The surface of this 
spring pond is 7 feet above the level of the hatchery floor, which gives 
an ample fall of water. This spring, called the upper spring to distin- 
guish it from a second one underneath the hatchery, is the sole feeder 
of the spring pond, and not only furnishes all the water used in the 
hatchery, but a considerable excess for which other avenues of escape 
have been provided; but the demand for water to develop eggs of the 
whitefish in the hatchery is not supplied directly from the spring pond, 
as the temperature of the latter during the hatching season is suffi- 
ciently warm to bring forth the fry earlier than is usually deemed de- 
sirable. The temperature of the water at its immediate source is 479, 
never fluctuating more than a small fraction of a degree, while in the 
spring pond it is variable, depending, of course, on the temperature of 
the atmosphere; but, owing to the constant and abundant influx of 
spring water, is kept warmer than is desirable for incubating eggs of 
the whitefish, except during brief periods of extremely severe weather. 
The average temperature of the spring pond, then, through the winter 
season will approximate 43°, which would bring forth the fry in from 
80 to 90 days, or about the 1st of February. Aside from the considera- 
tion of the existence of food for the young fishes at the period indi- 
cated, about which there may be no uncertainty, the advisability of 
allowing a too rapid development of the embryos may be considered 
questionable from the fact that when brought forward in this manner 
they suggest prematurity, shown by their vague and shadowy outlines, 
which present a decided contrast as compared with the fruit of 120 to 
150 days’ incubation, the latter having black and fully developed forms, 
evidently better fitted to survive or escape the vicissitudes necessarily 
attending their infantile period. 
At the time of the construction of the hatchery no information con- 
cerning the temperature of the spring pond during the winters season 
could be obtained, no record having been made; however, as it was 
known to contain but little ice even in the most severe winters, steps 
were taken with a view to aid in securing the desired reduction in tem- 
perature. The water must be exposed still further to the influence of 
cold winter air; an artificial pond must be arranged, and into this must 
