224 



BULLETIN OP THE BUREAU OF FISHERIES. 



Table 9.— Transmission of Sun's Energy by the Water of Seneca Lake Off Hector Point, 



N. Y., Aug. i, 1918. 



[Note. — 1.50 to 2.23 p. m., Government time=i2.4o to i.ii sun time. Transparency 6.8 m.] 



Hour, p. m. 



1.50 

 i-SS 

 1-57 

 1.38 

 1-59 

 2.00 

 a. 01 

 a. 03 

 a. OS 



Depth ! 



in 

 centi- I 

 meters. 



Read- 

 ing. 



127.8 

 126. 7 

 83.0 

 84.0 

 77.0 

 77. o 

 59- S 

 50.0 

 SO. S 

 Sl-5 

 45-8 

 45- S 

 40.6 

 40. 2 

 3S-8 

 36.5 

 32-3 

 32.1 



Deflec- 

 tion. 



} ' 



117. o 

 0-3 

 64.0 

 47-3 



38. S 



33-2 

 28.3 

 24.1 



Hour. p. m. 



2.07 

 2.09 

 2.12 

 2.14 

 2.17 

 2.18 



223 



Depth 



centi- 

 meters. 



700 

 800 



Zero. 



12. 1 

 12. 1 

 12. 2 

 12. 2 

 12. 1 

 12. 1 

 12. 2 

 12. 2 

 12. a 



12. 2 



12. 1 

 12.3 

 12. 2 

 12. 2 

 12.2 



12.2 

 12.4 

 12.3 



Read- 

 ing. 



29. 2 

 29. 2 

 24. 2 

 24.0 

 20.3 

 20. 5 

 18. 1 

 18. 1 

 16. 2 

 16. 1 

 IS- I 



15. 1 



IS-O 

 14. s 



14.4 



14. 6 

 14.6 



Deflec- 

 tion. 



17. 1 

 II. 9 



8.3 

 5-9 

 4.0 



2.9 



NOTES ON ABOVE TABLE. 



1. Sky perfectly clear and sun's radiation steady; no clouds; practically no haze. Light south 

 air, causing ripples on surface. Some swell from wind of yesterday and of early morning. The 

 swell caused irregularities of reading in upper water, as it raised and lowered the boat. At 100 cm. 

 the scale moved over 4 to 5 divisions, and reading had to be estimated under these conditions. This 

 effect became less as depth increased. Ripples cause a quivering of the reading in the galvanometer 

 but are too small to cause swings of the scale. 



2. In reading the direct sun a shunt coil is included in the circuit in order to keep the reading 

 within the limits of the scale. This coil is cut out by a switch when the receiver is used in water. The 

 reading in air must be multiplied by 1.89 to reduce it to the same scale as those in the water. Its value, 

 therefore, on this occasion is 221 divisions. One division equals 0.059 cal./cm.-/min., so that the sun 

 was delivering about 1.30 cal./cm.^/min. 



3. The observations not reported included a repetition of several of the readings, and a second 

 reading in the air, which gave a value of 116.2 divisions, or substantially the same as the first reading. 



4. The numbers in the columns headed zero, reading, deflection, indicate divisions of the scale of 

 the galvanometer. 



From these readings may be computed the value of the energ}' delivered by the 

 sun at different depths of the lake, as is shown in the following table: 



Table 10. — Calories per Square Centimeter per Minute Found at Various Depths of Seneca 



Lake, Aug. i, 1918. 



Depth in centi- 

 meters. 



In air 



2S-.. 



JO... 

 100. . . 

 150.. . 

 200.. . 



Per cent. 



100. o 

 31.8 

 29. o 

 ai. 4. 

 17-4 

 150 



Cal./cm.V 

 min. 



I- 30 

 .41 

 .38 

 .28 

 . 23 



Depth in centi- 

 meters. 



2SO. , 



300., 

 3SO-. 

 400. . 

 SOO.. 

 600.. 



Depth in centi- 

 meters. 



700 



800 



900 



1,000 



Per cent. 



2.7 

 1.8 

 1.3 



I. o 



Cal./cm.V 

 min. 



o. 0.15 

 ■Oi3 

 .017 

 .013 



