FISHES OF THE CONNECTICUT LAKES. 67 
depths. The source is in the immediately surrounding timber-covered 
hills or mountains. The prevailing trees are black spruce (P2cea 
mariana), yellow birch (Betula lenta), sugar or rock maple (Acer 
saccharum), and American beech (Fagus americana), with an un- 
dergrowth of speckled alder (Alnus incana) and other shrubs and 
herbs of northern New Hampshire. In the aggregate there is con- 
siderable sphagnum swamp in the drainage basin contiguous to this 
and the neighboring lakes. The water acquires its color, no doubt, 
during its slow seepage through the forest and marsh land by taking 
up considerable organic matter in solution. 
Main Inlet—The Main Inlet for a mile and a half before enter- 
ing First Lake meanders through an extensive meadow, the upper 
part with appreciable current, but the lower half or three-fourths 
mile sluggishly, with much shallow water on each side of the chan- 
nel and many lagoon-like bays indenting the shore. The depth 
varies from 4 feet in the channel to an inch or less on the muddy 
bars. The stream has its temperature lowered from some cause in the 
last mile of its course to the extent of 2° F. Vegetation is abundant, 
especially in the shallower portions. Bur-reed (Sparganium simplex 
and S. simplex angustifolium), pond weed (Potamogeton ampli- 
jolius and P. nuttallii), needle rush (leocharis acicularis), and 
the yellow pond liles (Vymphewa advena and N. hybrida) 
predominate. 
Temperature of the water—The temperature of the sources of 
supply was during the summer season the same for all streams enter- 
ing from wooded land, namely 55° F., or 13° or 14° lower than the 
surface temperature of the lake during the greater part of the 
season and equal to the temperature at a depth of about 25 feet. 
The Main Inlet at its entrance during the mid-season was 64° F., 
after being cooled by the addition of cool water through seepage. 
The water entering from near-by springs was colder, registering 50°. 
The temperature of all springs rising in the mountains registered 
42° at their sources. Contact with the air soon raised their tem- 
perature to 55°. 
The surface temperature of the lake water underwent a change 
of 10° during the period of observation. It was learned that the 
ice broke up and left the lake May 9, 1904; temperature 32° F. On 
June 28 the surface registered 66° F. The maximum temperature 
was registered on July 19 and 20—72.5° F., which fell by Septem- 
ber 10 to 62° F. A fall of rain accompanied by wind usually caused 
a lowering of the surface temperature of 14° to 2°. The original 
temperature was regained, however, in twelve to thirty-six hours 
during the warmest part of the season. In the latter part of the 
season the decline of surface temperature was by these sudden drops, 
from which there seemed to be no recovery. South Bay had a maxi- 
pyro 
mum temperature of 75° F. on July 19. This high temperature is 
