158 Things not generally Known. 



WARMTH OF SNOW IN ARCTIC LATITUDES. 



The first warm Snows of August and September (says Dr. 

 Kane), falling on a thickly-bleached carpet of grasses, heaths, 

 and willows., enshrine the flowery growths which nestle round 

 them in a non-conducting air chamber ; and as each successive 

 snow increases the thickness of the cover, we have, before the 

 intense cold of winter sets in, a light cellular bed covered by 

 drift, seven, eight, or ten feet deep, in whioh the plant retains 

 its vitality. Dr. Kane has proved by experiments that the 

 conducting power of the snow is proportioned to its compres- 

 sion by winds, rains, drifts, and congelation. The drifts that 

 accumulate during nine months of the year are dispersed in 

 well-defined layers of different density. We have first the 

 warm cellular snows of fall, which surround the plant ; next 

 the finely-impacted snow-dust of winter ; and above these the 

 later humid deposits of spring. In the earlier summer, in the 

 inclined slopes that face the sun, as the upper snow is melted 

 and sinks upon the more compact layer below it is to a great 

 extent arrested, and runs off like rain from a slope of clay. The 

 plant reposes thus in its cellular bed, safe from the rush of 

 waters, and protected from the nightly frosts by the icy roof 

 above it. 



IMPURITY OF SNOW. 



It is believed that in ascending mountains difficult breath- 

 ing is sooner felt upon snow than upon rock ; and M. Bous- 

 singault, in his account of the ascent of Chirnborazo, attributes 

 this to the sensible deficiency of oxygen contained in the pores 

 of the snow, which is exhaled when it melts. The fact that 

 the air absorbed by snow is impure, was ascertained by De 

 Saussure, and has been confirmed by Boussingault's experi- 

 ments. Quarterly Review, No. 202. 



SNOW PHENOMENON. 



Professor Dove of Berlin relates, in illustration of the for- 

 mation of clouds of Snow over plains situated at a distance 

 from the cooling summits of mountains, that on one occasion a 

 large company had gathered in a ballroom in Sweden. It was 

 one of those icy starlight nights which in that country are 

 so aptly called "iron nights." The weather was clear and 

 cold, and the ballroom was clear and warm ; and the heat was 

 so great, that several ladies fainted. An officer present tried 

 to open a window ; but it was frozen fast to the sill. As a last 

 resort, he broke a pane of glass ; the cold air rushed in, and it 

 snowed in the room. A minute before all was clear j but the 



