PISHES OF THE CONNECTICUT LAKES. 67 



depths. The source is in the immediately surrounding timber-covered 

 hills or mountains. The prevailing trees are black spruce {Picea 

 mariana), yellow birch {Betida lenta), sugar or rock maple {Acer 

 sacchamim), 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. si?nplex angustifoUum) , pond weed (Pofamogeton ampJl- 

 f alius and P. nuttallii)^ needle rush {Eleocharis acicularis), and 

 the yellow pond lilies {Nymphcea advena and N. hyhriddS 

 predominate. 



T empevature of the water. — The temperature of the sources of 

 supply was during the summer season the same for all streams enter- 

 ing from w^ooded 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 1|° 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- 

 mum temperature of 75° F. on July 19. This high temperature is 



