148 Royal Society :— 
that in the basin cover. A very slow thawing process was going on 
in the jar the whole time, as was evident by the state of the indi- 
cating piece of ice there present. 
Pieces of good Wenham-lake ice were prepared, some being blocks 
three inches square, and nearly an inch thick, others square prisms 
four or five inches long: the blocks had each a hole made through 
them with a hot wire near one corner ; woollen thread passed through 
these holes formed loops, which being attached to pieces of lead, 
enabled me to sink the ice entirely under the surface of the ice-cold 
water. Each piece was thus moored to a particular place, and, be- 
cause of its buoyancy, assumed a position of stability. The threads 
were about 13 inch long, so that a piece of ice, when depressed 
sideways and then left to itself, rose in the water as far as it could, 
and into its stable position, with considerable force. When, also, a 
piece was turned round on its loop as a vertical axis, the torsion 
force tended to make it return in the reverse direction. 
Two similar blocks of ice were placed in the water with their 
opposed faces about two inches apart; they could be moved into 
any desired position by the use of slender rods of wood, without 
any change of temperature in the water. If brought near to each 
other and then left unrestrained, they separated, returning to their 
first position with considerable force. If brought into the slightest 
contact, regelation ensued, the blocks adhered, and remained ad- 
herent notwithstanding the force tending to pull them apart. They 
would continue thus, even for twenty-four hours or more, until they 
were purposely separated, and would appear (by many trials) to 
have the adhesion increased at the points where they first touched, 
though at other parts of the contiguous surfaces a feeble thawing 
and dissecting action went on. In this case, except for the first 
moment and in a very minute degree, there was no pressure either 
from capillary action or any other cause. On the contrary, a 
tensile force of considerable amount was tending all the time to 
separate the pieces of ice at their points of adhesion ; where still, I 
believe, the adhesion went on increasing—a belief that will be fully 
confirmed hereafter. 
Being desirous of knowing whether anything like soft adhesion 
occurred, such as would allow slow change of position without sepa- 
ration during the action of the tensile force, I made the following 
arrangements. The blocks of ice being moored by the threads 
fastened to the lowest corners, stood’ in the water with one of the 
diagonals of the large surfaces vertical; before the faces were 
brought into contact, each block was rotated 45° about a horizontal 
axis, In opposite directions, so that when put together, they made a 
eompound block, with horizontal upper edges, each half of which 
tended to be twisted upon, and torn from the other. Yet by placing 
indicators in holes previously made in the edges of the ice, I could 
not find that there was the slightest motion of the blocks in rela- 
tion to each other in the thirty-six hours during which the experi- 
ment was continued. This result, as far as it goes, is against the 
necessity of pressure to regelation, or the existence of any condition 
like that of softness or a shifting contact; and yet I shall be able to 
, ee ee ee SS lS Se 
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