436 FE. Hungerford—Observations on Snow and Ice 
ular plasticity of ice, whether Ae = mass or in the form of 
minute snow crystals. The m n of these points, around 
which the interest of the pepe cutest: will enable the 
reader to follow the details more intellige 
y method of conducting the trials vith prisms of ice is as 
follows: The prisms are obtained by sawing a block of lake 
ice into slabs an inch or two ne and “gain sawing the slabs 
on 
mp, 
which should be light (made with, perhaps, half inch wooden 
a half inch thick and three inches wide), two prisms can be 
treated at the same time. The fractured faces of the prism are 
ipa together, and when they have been carefully adjusted, 
e clamp may be laid over the ends of the two prisms which 
tie parallel and near to each other on the table. The screws 
are then gently tightened. To avoid heat and moisture the 
handling should be done, if they are bandied at all, with a cold 
cloth ; or they may be pushed about with a chilled knife blade 
to get them into position. All my work was done in a cold 
shed, which was kept open to the weather. It will be noticed 
that in these trials, both with prims and with snow, the temper- 
atures were carefully noted, 2 — intervals, during the 
progress of the trial. These are the natural te emperatures of 
the room where the work was rien and so of all the apparatus 
concerned in the experiment 
ith these explanations I submit several illustrations of the 
behavior of ice prisms under a light pressure. These are in the 
form of abstracts pct directly from my note-books, with only 
such corrections and explanations as seem necessary to a full 
understanding of each trial. 
JANUARY 27th, 1869.—Temperature ranged from 12° F. to 22° F. during the fol- 
lowing trials, which began on the 26th. Prisms of ice an inch thick by two 
inches were broken, and after matching them on the lines of fracture, were 
placed in clamps and subjected to a’moderate pressure, the screws being tight- 
ened several times during the experiment. One — yas parted on the evening 
nd sho iti 
e one that was permi = remain in the ¢ 04 over night, therefore, 
some twenty-four hours, was so firmly reunited that i endeavoring to part it I 
thought the ice would break slaserhier ere. Tt fi nally yielded on the old joint to a 
force little less than sufficient to break the ice in any direction. There had evi- 
dently been a firm reunion, not a mere sticking Sasthae but a knitting of the 
joint. 
Loerie > 1869. —Temperatures for Feb. 2d to vie 3d. Feb. 2d, 104 
7° ¥., 5,30 . 18° F., OP. MIE’ F., 9.4. 0. of Feb. 3d, 20° F- Highest Honing 
20° F. The “ of the 2d of "February was bright ure 
