THE STEUCTUEE MOTION OF GLACIEES. 
329 
of viscosity already referred to, and which, though it has been overlooked hitherto, must 
play a part of the highest importance in the phenomena of the glacier world. 
§ 3. On the Regelation of Ice^ and its apjplication to Glacial Phenomena. 
In a lecture given by Mr. Faeadat at the Koyal Institution on the 7th of June, 
1850, and briefly reported in the ‘Athenseum’ and ‘Literary Gazette’ for the same month, 
it was shovm that when two pieces of ice, at 32° Fahe., with moistened surfaces, were 
placed in contact, they became cemented together by the freezing of the film of water 
between them. When the ice was below 32°, and therefore dry, no adhesion took place 
between the pieces. Mr. Faeaday referred, in illustration of this point, to the weU- 
known experiment of making a snowball. In frosty weather the dry particles of ice will 
scarcely cohere, but when the snow is in a thawing condition, it may be squeezed into a 
hard compact mass. On one of the warmest days of last July, when the thermometer 
stood at upwards of 80° Fahe. in the shade and above 100° in the sun, a pile of ice- 
blocks was observed by one of us in a shop window, and he thought it interesting to 
examine whether the pieces were united at their places of contact. Laying hold of the 
topmost block, the whole heap, consisting of several large lumps, was lifted bodily out 
of its vessel. Even at this high temperature the pieces were frozen together at the 
places of contact, though the ice all round these places had been melted away, leaving 
the lumps in some cases united by slender cyhnders of the substance. A similar experi- 
ment may be made in water as hot as the hands can bear ; two pieces of ice will freeze 
together, and sometimes continue so frozen in the hot water, until, as in the case above 
mentioned, the melting of the ice around the points of contact leaves the pieces united 
by slender columns of the substance. 
Acquainted with these facts, the thought arose of examining how far, in virtue of the 
property referred to, the /bm of ice could be changed without final prejudice to its con- 
tinuity. It was supposed that though crushed by great pressure, new attachments 
would he formed by the cementing, through regelation, of the severed surfaces ; and that 
a resemblance to an efiect due to viscosity might be produced. To test this conjecture 
the follo’wing experiments were made : — Two 
pieces of seasoned boxwood, A and B, fig. 2, 
4 inches square and 2 deep, had two cavities hol- 
lowed out, so that when one was placed upon 
the other, a lenticular space, shown in section at 
C, was enclosed between them. A sjghere of 
compact, transparent ice, of a volume rather 
more than sufficient to fill the cavity, was placed 
between the pieces of wood, and subjected to 
the pressure of a small hydraulic press. The 
ice broke, as was expected, but it soon re- 
attached itself; the pressure was continued, and in a few seconds the sphere was 
MDCCCLVII. 2 X 
Fig. 2. 
