FINGER LAKES OF NEW YORK. 



231 



radiation from the sun is sure to be variable; the approach to the sun of a white cloud 

 momentarily raises the radiation and unnoticed wisps of cloud may reduce it. In 

 the series it is clear that the mean of the readings at 200 cm. is too low as compared 

 with all of the others, since the transmission in the i to 2 m. stratum should be about 

 the same as below. The value of 12.8 per cent has been assumed, therefore, for the 200 

 cm. level and a mean transmission of about 66 per cent per meter. Under these condi- 

 tions about 99 per cent of the sun's energy would be delivered to the upper 8 m. of 

 water, somewhat more than 80 per cent going to the first meter, or with mean sun about 

 82 per cent. 



It will be noted that corresponding with the smaller transparency of the water, as 

 compared with Seneca Lake, the transmission of radiation is decidedly lower. 



Table 14. — Transmission of Sun's Energy by Water of Canand.^igua L-\ke, Jixy 27, 1918, 11.37 



A. M. TO 12.03 P- M., GOVER.NTMENT TiME. (See fig. 5.)' 

 [Note. — Sky hazy. Transparency of water 4.4 m. Transmission per meter about 60 per cent.] 



B 250 



Fig. 5. — Work curves for Canandaigua Lake. (See explanation, fig. i.) 



The observations on Canandaigua Lake were also somewhat irregular, not on 

 account of clouds, but haze. The sky was cloudless, but the hills a few miles up the 

 lake were nearly invisible in the haze which filled the valley. Under such conditions 

 the value of the sun's radiation is much reduced, and it was found to be about 0.95 

 cal./cm.ymin. as compared with 1.30 cal. in the case of the two other lakes. The read- 

 ings of the sun at the beginning and end of the observations in the lake were in close 

 agreement. The readings of the first series taken in the water — those taken while 

 the receiver was going down — were also in close agreement and indicate that 18 to 

 19 per cent of the radiation in air was present at 100 cm. depth and that each meter 

 below that depth transmitted about 60 per cent of the radiation received by its upper 



