1882.] 



relative Thermal Intensity of the Sun. 



335 



horizontally with the stem at right angles to the direction of the sun's 

 rays, and sufficient time was always allowed for the thermometer to 

 assume its proper temperature before each reading was taken. 



Tosten Vierod, near Laurwig, Norway. 

 July 17th. Brilliant sunshine, cloudless sky, strong breeze. 



Time. Position of thermometer. Temperature. 



9.40 a.m. . On green grass 57'3° C. 



10.10 ,, . . On somewhat parched grass 61*2 



10.40 „ . . On bare soil 60*6 



11.10 ,, . . On staff 5 feet above meadow .... 50*5 



11.40 ,, . . On newly-mown grass 56*5 



12.40 p.m. . On white paper 73*5 



1.10 „ . . On staff as at 11.10 51*5 



Wilhelmshobe, Hesse Cassel. 



Time 11 a.m. to 1 p.m. August 16th. Brilliant sunshine. 



Position of thermometer. Temperature. 



On staff 5 feet above grass 51*8° C. 



On black caoutchouc 54" 7 



On white paper 68*7 



On glass mirror 64*0 



On black silk 56'5 



On slightly concave metallic mirror. . 64*0 



On grass 58 '5 



Pontresina, Switzerland. 

 September 7th. Clear and cloudless sky ; breeze. 

 Time. Position of thermometer. Temperature. 



1.10 p.m. . On staff 4 feet above ice of Morta- 



ratsch Glacier 43-9° C. 



I. 30 ,, . . On black caoutchouc laid upon glacier 39*0 



2.0 „ . . On bare ice of glacier 47'5 



2.30 ,, . . On white paper laid upon glacier . . 53*0 



Summit of Diavolezza Pass, Switzerland. 

 September 8th. Clear and cloudless except on horizon. 



Time. Position of thermometer. Temperature. 

 10.30 a.m. . On staff 4 feet above snow 48'6° C. 



II. ,, . . On black caoutchouc laid upon snow 39'1 



11.30 ,, . . On bare snow 61 '9 



12.0 noon. On white paper laid upon snow . . 65'5 



