PLANTS IN WINTER. 
2G7 
round them in a non-conducting air-chamber; and, as 
each successive snow increases the thickness of the 
cover, w r e have, before the intense cold of winter sets 
in, a light cellular bed covered by drift, six, eight, or 
ten feet deep, in which the plant retains its vitality. 
The frozen subsoil does not encroach upon this narrow 
zone of vegetation. I have found in midwinter, in this 
high latitude of 78° 50', the surface so nearly moist as 
to be friable to the touch; and upon the ice-floes, 
commencing with a surface-temperature of —30°, I 
found at two feet deep a temperature of —8°, at four 
feef +2°, and at eight feet +26°. This was on the 
largest of a range of east and west hummock-drifts in 
the open way off Cape Stafford. The glacier which we 
became so familiar with afterward at Etah yields an 
uninterrupted stream throughout the year. 
“My experiments prove that the conducting power 
of the snow is proportioned to its compression by winds, 
rains, drifts, and congelation. The early spring and 
late fall and summer snows are more cellular and less 
condensed than the nearly impalpable powder of 
winter. The drifts, therefore, that accumulate during 
nine months of the year, are dispersed in well-defined 
layers of differing density. We have first the warm 
cellular snows of fall which surround the plant, next 
the fine impacted snow-dust of winter, and above these 
the later humid deposits of the spring. 
“ It is interesting to observe the effects of this dispo¬ 
sition of layers upon the safety of the vegetable growths 
below them. These, at least in the earlier summer, 
