Prof. Faraday on Regelation. 149 
show that there is either soft adhesion or an equivalent for it, and 
from that state draw still further cause against the necessity of pres- 
sure to regelation. 
Torsion force was then employed as an antagonist to regelation. 
The ice-blocks, being separate, were adjusted in the water so as to be 
parallel to each other, and about 1} inch apart. If made to ap- 
proach each other on one side, by revolution in opposite directions 
on vertical axes, a piece of paper being between to prevent ice con- 
tact, the torsion force set up caused them to separate when left to 
themselves; but if the paper were away and the ice pieces were 
brought into contact, by however slight a force, they became one, 
forming a rigid piece of ice, though the strength was, of course, very 
small, the point of adhesion and solidification being simply the con- 
tact of two convex surfaces of small radius. By giving a little 
motion to the pail, or by moving either piece of ice gently in the 
water with a slip of wood, it was easy to see that the two pieces were 
rigidly attached to each other; and it was also found that, allowing 
time, there was no more tendency to a changing shape here than in 
the case quoted above. If now the slip of wood were introduced 
between the adhering pieces of ice, and applied so as to aid the 
torsion force of one of the loops, 7. e. to increase the separating force, 
but unequally as respects the two pieces, then the congelation at the 
point of contact would give way, and the pieces of ice would move 
in relation to each other. Yct they would not separate; the piece 
unrestrained by the stick would not move off by the torsion of its 
own thread, though, if the stick were withdrawn, it would move 
back into its first attached position, pulling the second piece with it ; 
and the two would resume their first associated form, though all the 
while the torsion of both loops was tending to make the pieces 
separate. 
If when the wood was applied to change the mutual position of 
the two pieces of ice, without separating them, it were retained for a 
second undisturbed, then the two pieces of ice became fixed rigidly 
to each other im their new position, and maintained it when the 
wood was removed, but under a state of restraint; and when suffi- 
cient force was applied, by a slight tap of the wood on the ice to 
break up the rigidity, the two pieces of ice would rearrange them- 
selves under the tersion force of their respective threads, yet remain 
united ; and, assuming a new position, would, in a second or less, 
again become rigid, and remain inflexibly conjoined as before. 
By managing the continuous motion of one piece of ice, it could 
be kept associated with the other by a flexible point of attachment 
for any length of time, could be placed in various angular positions 
to it, could be made (by retaining it quiescent for a moment) to 
assume and hold permanently any of these positions when the ex- 
ternal force was removed, could be changed from that position ito 
a new one, and, within certain limits, could be made to possess at 
pleasure, and for any length of time, either a flexible or a rigid attach- 
ment to its associated block of ice. 
So regelation includes a flexible adhesion of the particles of ice, 
and also a rigid adhesion. The transition between these two states 
