414 Chronicles of Science. [July, 



7° or 8° F., and even on the peak of Mont Cervin itself they more 

 than once saw traces of a thaw. 



As a compensation for the unlooked-for mildness of the winter 

 climate, the summer at the station was extraordinarily cold. The mean 

 temperatures of the three summer months was 32°*3, and that of July, 

 only 3 3° * 5. These are the lowest average summer temperatures 

 that have ever been reported ; for the mean of Dr. Kane's stations in 

 Smith Sound was 35° ■ 4 for the summer, and 39° ■ 9 for July. It is 

 well known that at Yakutsk and other stations in Siberia, as well as 

 in North America, where the winter temperature is excessively low, 

 the heat of the summer is comparatively high, approaching and even 

 surpassing that observed in these islands. The result is that a rapid 

 and vigorous, though short-lived, vegetation is produced. 



It is hopeless to look for anything of this nature on the Pass of 

 St. Theodule, where frost occurs every night. The perpetual sun- 

 shine of an Arctic summer effectually prevents any damage to the 

 growing plants from this cause. 



The annual march of temperature at high stations is remarkable. 

 Comparing the observations now under discussion with those from 

 other stations at somewhat lower levels, Dr. Hann finds that Feb- 

 ruary is the coldest month, sometimes even March, while December 

 is extraordinarily mild. In this month it is found that the tempe- 

 rature increases with the elevation owing to the accumulation of cold 

 air in the hollows. 



This fact shows the great difficulty of determining accurately 

 the decrease of temperature with height, in any district, the local 

 conditions which influence the result being so very various. How- 

 ever, the Swiss observations throw some light upon it, and Dr. Hann 

 has submitted to the Academy at Vienna a paper on the subject, in 

 which he has calculated provisionally a table to show the rate of this 

 decrease. From this paper we learn that the level of the isothermal 

 contour of 32° varies from 1100 feet in January to upwards of 

 11,000 in July. If we look for an annual temperature of 0° F., 

 which is about that of Kensselaer Harbour, we find it to lie about 

 2000 feet over the top of Mont Blanc, while the lowest July tem- 

 perature at sea level, that of Northumberland Sound, is met with at 

 the level of 10,000 feet in the Alps. 



Comparatively little is said about the other meteorological 

 elements. The barometer is dismissed with a few words ; but as 

 regards the distribution of moisture the author goes into more 

 length. In winter the air on the mountain tops is dry and clear ; 

 in summer it is much more cloudy. The action of the " courant 

 ascendant" is analogous to the foregoing, for the mornings are much 

 less commonly cloudy than the afternoons. As to the actual 

 amount of precipitation at the upper stations, as compared with the 

 lower, there is not much to say. The data for rain and snow are 



