158 Prof. Bischoff'o/i the Teinperatiire of 



The soil near Tnterlacken towards the lake of Brienz, . . 03.05 © 



50.30 Sh. 



Mean 59.0? 



40 paces from the lake of Brienz, . . . 58.55 



. — 8 paces from the lake of Brienz, . . . 55.40 Sh. 



Mean 50.97 



Thus, the temperature of the surface of the earth decreased 

 2°.92 from Untcrsecn towards the lake of Thtin, as well as to- 

 wards the lake of Brie7irj. But where the observations were made 

 on the shore of the lakes, they become gradually deeper and 

 deeper ; and the deepest points in both lakes are at a great dis- 

 tance from the shore. 



The following observations also prove the cooling influence of 

 the bottoms of lakes on their banks. 



Near Darligen, on the lake of Thun, . . . 67.8? 



At Aesclii on the Niesen, 930 feel above the lake of Thun. 57.20 



56.05 Sh. 



Mean 50.02 

 At the lake of Brienz, near the Gieshach, and not far from the place 



where the lake is deepest, ..... 53.37 © 

 1 578 feet above the lake of Brienz, higher up than the waterfalls, 63.37 Sh. 



Notwithstanding the immense difference of elevation between 

 these two points, the temperature of the soil was the same. But 

 I do not mean to maintain that there is no decrease of tempera- 

 ture between these two points. The mean temperature of the 

 point situated 1578 feet above the lake of Brienz would cer- 

 tainly be found lower than that on the bank of the lake. At 

 the time that I made those solitary observations, the tempera- 

 ture of the soil at a depth of 1 foot was above the mean ; but 

 more so at the higher point than near the lake, because the 

 yearly maximum occurs later in higher regions than in valleys. 

 Hence the equality of the temperatures observed at the two 

 points, notwithstanding their considerable difference of elevation. 

 However, it may almost with certainty be assumed, that, owing 

 to the cooling influence of the bottom of the lake on the lower 

 point, a smaller decrease of temperature would be found between 

 these two points, than in places where no such cooling influences 

 exist. 



