Geology and Mineralogy. 329 
ence. 17. With a constant difference of potential — the 
coatings of a condenser, the electric strains in the successive 
pede of the substance between these coatings vary fous time 
time.—Annalen der Physik und Chemie, No. 8, 1880, p. ips 
A Phenomenon of Elasticity.— elastic gum is maemads 
then expanded and wound in a spiral upon a glass tube or a wire 
and cooled for a short time in a cooling mixture, it show 
tendency to aontasof, but when it is submitted to "hot tio it 
disposition to return to its original length; but if one preg ae it 
in hot water it contracts to } or } and remains contracted to the 
third or fourth of its original eaeth, axwell found oat 
pamepense in gutta percha, when this was fe Rica to expand- 
Ing influences when in a cool condition. These are sere marke 
Be ibe: ‘of the secondary effects of elastic city.—LProc. Edin. 
.S., xX, 1879, p. 52; Beiblitter Annalen der Physik und Uiaia 
No. 6, 1880, p. 422. 
This property of rubber and gutta percha is significant in view 
of the recent experiments of Professor A. Graham Bell wpe the 
effect of radiant energy upon thin discs of rubber. Jot 
Il. GroLoagy AND MINERALOGY. 
1. Moving snow-mass ve Tuckerman Ravine, White Mountains, 
H 
New Hampshire.—Mr. . Prcxerina gives the following 
account of an excursion, ye uly, 1879, to this glacier-like snow-mass, 
of “A 
in the number ppalachia” for Jun ne, 188 
The walk from the Crystal Cascade ‘through the ravine was 
uneventful, and in about three hours I reached the snow patch. 
Much of the snow had melt Ited, so that some of the stones placed 
upon it were gone, but of those that remained the middle on es had 
more unusual than agreeable. From the above, it would appear 
that we have here ag same glacial action that occurs on a much 
larger scale in the Alps, the same transportation, and therefore 
grinding, and polishing of the rocks, the same phenomena of 
viscosity and regelation; only that we here miss the long tongues 
with their accompanying crevasses. Our snow- natch, 
called an sapien glacier. 
