1874.] 



Thermometric Observations in the Alps. 



323 



spirit thermometer (unverified), fixed to a post 4 feet above the snow, 

 recorded 18 Fahr. as the minimum temperature during the night of 

 December 29-30th. At 2 P.M. the thermometer in the shade stood at 

 12-8C. The air was apparently equally clear throughout the whole 

 day. The following readings of the blackened bulb in vacua in sunshine 

 were made : 



At Greenwich the readings were, with blackened bulb in vacuo : 

 maximum 22-9 C. (73-2 Fahr.) ; at 9 A.M., 2-7 C. (36-9 Fahr.) ; and at 

 3 P.M., 22-9 C. (73-2 Fahr.). The maximum in the shade was 7'5 C. 

 (45-5 Eahr.), and the minimum on grass in the shade was 4 0> 9 C. (23 0< 1 

 Fahr.). 



December 31st. Sky deep blue, sun quite free from clouds during the 

 whole day. Very light streaks of cloud appeared in the S.W. just 

 before sunset. Barometer 621 '5 millims. At 8 A.M. the thermometer on 

 the snow registered 23'6 C. ; at noon the thermometer in the shade 

 stood at 10'C. A naked thermometer with smoked black glass bulb 

 freely suspended registered only 2 0> 8 C. at 9.30 A.M. in sunshine. 

 During the day abundance of snow crystals were frequently observed to be 

 floating about in the air. The blackened bulb in vacuo was read in the 

 sunshine as follows : 



At Greenwich the readings were, with blackened bulb in vacuo : 

 maximum 24-4 C. (76 Fahr.) ; at 9 A.M., 8-l C. (46-6 Fahr.) ; at noon, 

 21-3 C. (70-4 Fahr.) ; and at 3 P.M., 24-4 C. (76 Fahr.). The maxi- 

 mum in the shade was 10'4 C. (50*7 Fahr.), and the minimum on grass 

 in the shade was 0-6 C. (33-l Fahr.). 



January 1st, 1874. A cloudy morning. Sun only slightly visible 

 before 9 A.M.; afterwards brilliant between the clouds. Barometer 

 625 millims. At 8.15 A.M. the thermometer on the snow marked 

 13-9 C., and the unverified self -registering minimum -17-3C. At 

 11.30 A.M. the thermometer in the shade stood at -3-3 C. The following 

 readings of sunshine temperatures were made with the blackened bulb in 

 vacuo : 



