Contents xlv 



PAGE 



which (litter from each other in their maximum depth. 



The lines separating them are shown >n the chart, p. 339 3 1 3 

 Prevailing winds blow at right angles to the axis of 



the 1, 



Dates on which extended observations \\ere made. 

 Description of thermometers used. 



iphic methods used to show the character of the 



thermal distribution . . . . . . 31 j 



( 'har.u trusties of vernal and autumnal distributions 315 

 Table I gives observations made on i8th August. 



1885 . ... .... 316 



Table II gives those made on 5th September . . 317 

 Both tables show autumnal characteristics . . 318 

 Temperature on steepest gradient determined at 



fathom ........ 319 



Table III Observations on 22nd September . . 320 

 Thr autumnal character is more accentuated . . 321 

 Table IV Observations on 1 5th October . . ^jj 

 ( 'in vs of temperature observed I5th October . 323 

 ; mal influence of streams entering the lake . 324 

 Table VI. Temperature on steepest gradients on 



i')th October ... ... 325 



The isothermal surfaces in the lake are not planes; 



they are tortuous surfaces which exhibit considerable 



and irequent variations of curvature. 



Table VII. Observations on 14th November . 326 



it cooling had taken place since I5th October . 327 

 Curves ot temperature in the different basins . . 328 

 1 >i- n^sion of observations in the Luss basin . . 329 

 The water contains a maximum of heat in the third 



weekofSeptembercoinciding with theautumnal equinox 

 Table IX. Dimensionsnf thermal exchanges in the 



basin ......... 330 



In u>m^ the curves as a means of discussing the- heat 



exchanges in the body of the water it is convenu -nt to 



i linr.ti he.it unit, and lor this JMIIJ>OM- the tathom 



Fahrenheit has been 1. As the British 



<|ual to i -.S ^ metres. and the Centigrade degree 



is equal to 1-8 Fahrenheit degrees, it is obvious th.it 



idelltu al I .\a> tlv 

 10, n Fahr Cent. . 



\iinum trm]> ... 



d2 



