A LIMNOLOGICAL RECONNAISSANCE 



21 



each number. In Col. D, 0.00 is omitted at the left of each number; 

 the significant figures only being employed in each case. 



2. Multiplication is done by Crelle's tables, using three significant 

 figures. The difference in the total of direct and distributed work is 

 due to omitting some of the final figures in multiplying. 



3. The direct work in the 10 m.-15 m. and 15 m.-20 m. strata is 

 the sum of the work of the single meters, as is the case in the strata 

 above. It is therefore not exactly the product of the numbers in 

 Cols. C and D. 



4. Col. C, Factor, gives the product RT • Dm for each stratum. 

 Col. D, 1-D, gives the significant figures showing the loss of density. 

 1.000,000 — D. Col. E gives the amount of work per square centimeter 

 of surface of the lake, necessary to raise the stratum from 4° to the 

 temperature stated by mixture of warm water from the surface. 



Fig. 3. Curves showing the direct work, the distributed work, and the effect of direct 

 insolation. See pp. 19-26. The curves extend to the depth of 20 meters. The entire 

 area enclosed by the curve of distributed work, ABDEH, is equal to that of the direct 

 work, AGGH. The area, ACDB, gives the direct effect of the sun, and the area, 

 ACDEH, that of the wind. 



The table shows that about 1600 g. cm. of v/ork per sq. 

 cm. of surface of the lake were needed to distribute 21,000 

 cal. per sq. cm. through the water of the lake. The upper 

 and warmer strata of the lake required most of this work. 

 The deeper strata needed very little. The reasons for this 

 are found partly in the small volume of the lower strata, 

 partly in their lower temperature, and partly in the fact 



