318 Prof. Frankland on some Winter [May 7, 



According to Dufour's trigonometrical measurements, Davos is 1556 

 metres, or 5105 feet, above the sea; the measurements of the Swiss 

 Meteorological Society make the height 1650 metres, or 5413 feet ; and 

 my own estimation with an aneroid gave it as 4000 feet above Zurich, 

 or 5352 feet above the sea. The village of Davos is therefore about 500 

 feet lower than the summit of the Rigi. 



I arrived on the evening of the 20th of December, and found the snow 

 lying from two to three feet deep on the flat sole of the valley. On the 

 following morning the thermometric observations were commenced with 

 instruments supplied to me by Mr. L. Casella, all of which had been 

 certified at the Kew Observatory. For the corresponding readings at 

 Greenwich I am indebted to Mr. Glaisher. 



December 21s, 1873. From behind the sharp peak of the Schwarz- 

 horn the sun rose at the Seehof Hotel, Davos-Dorfli, at 8.35 A.M. 

 Throughout the day the sun was alternately clear and obscured by 

 clouds. At Davos-Platz it did not rise until 9.44 A.M. At 10 A.M. the 

 mercurial thermometer with blackened bulb in vacuo showed 44 C. 

 (lll-2 Fahr.) in the sunshine, and 45 C. (113 Fahr.) at 2.50 P.M. At 

 Greenwich the readings on this day with the blackened bulb in vacuo 

 placed on the grass * in the sunshine were : at 9 A.M., 9'3 C. (48* 7 

 Fahr.), at noon and at 3 P.M., 21-9 C. (71'5 Fahr.), the maximum 

 during the day being 21-9 C. (71 0< 5 Fahr.). The maximum tempera- 

 ture observed in the shade was 10'0 C. (51 0< 7 Fahr.), and the minimum 

 on grass in the shade 2-l C. (35'7 Fahr.). 



December 22nd. A mercurial thermometer with black glass bulb was 

 laid on the snow at 8 A.M. ; twenty minutes later, or fifteen minutes 

 before sunrise, it marked - 18-3 C. ( - 1 Fahr.). The sky was deep 

 blue, and almost perfectly cloudless during the whole day. Five minutes 

 after sunrise many of the patients at the Seehof Hotel were walking in 

 the open air without any special wraps, and many of them without over- 

 coats. In the brilliant sunshine one felt comfortably warm sitting in 

 front of the hotel in a light morning coat. The following thermometrical 

 observations were made on this day : 



* Since the above was written I have ascertained that the readings of this kind of in- 

 strument are much higher when it is laid on grass than when it is clamped upon a 

 staff at a height of 5 feet above the ground. Thus, at St. Leonard's-on-Sea on the 7th 

 of April last, this thermometer in sunshine stood at 42'3 C. at 11.50 A.M., when placed 

 5 feet from the ground, but when laid on the grass it promptly rose to 56 '5 C. It is 

 therefore evident that the readings of the solar thermometer at Greenwich, given 

 throughout this paper, are much too high for fair comparison with the Davos tempera- 

 ture, the thermometer at Greenwich having been always laid upon the grass. On 

 the 7th of April the sky at St. Leonard's was clear, the air warm with but little wind, 

 and the sun bright ; nevertheless the maximum temperature during the day in sunshine 

 was 2'7 C. lower than that observed with the same instrument at Davos on the 21st of 

 December last. May 7, 1874. 



