Prof. Faraday on Regelation. 153 
became so dissected at the surfaces as to develope the mechanical 
composition of the masses, and to show that they were composed of 
parallel layers about the tenth of an inch thick, of greater and lesser 
fusibility, which layers appear, from other modes of examination, to 
have been horizontal in the ice whilst in the act of formation. They 
had no relation to the position of the blocks in the water of my ex- 
periments, or to the direction of gravity, but had a fixed position in 
relation to each piece of ice. 
ADDENDUM. 
The following methed of examining the regelation phenomena above 
described may be acceptable. Take a rather large dish of water at 
common temperatures. Prepare some flat cakes or bars of ice, from 
half an inch to aninch thick ; render the edges round, and the upper 
surface of each piece convex, by holding it against the inside of a 
warm saucepan cover, or in any other way. When two of these pieces 
~ are put into the water they wiil float, having perfect freedom of motion, 
and yet only the central part of the upper surface will be above the 
fluid; when, therefore, the pieces touch at their edges, the width of 
the water-surface above the place of contact may be two, three, er 
four inches, and thus the effect of capillary action be entirely removed. 
By placing a plate of clean dry wax or spermaceti upon the top of a 
plate of ice, the latter may be entirely submerged, and the tendency 
to approximation from capillary action converted into a force of 
separation. When two cr more of such fioating pieces of ice are 
brought together by contact at some point under the water, they 
adhere ; first with an apparently flexible, and then with a rigid adhe- 
sion. When five or six pieces are grouped in a contorted shape, as 
an S, and one end piece be moved carefully, all will move withi 
rigidly ; or, if the force be enough to break through the joint, the 
rupture will be with a crackling noise, but the pieces will still adhere, 
and in an instant become rigid again. As the adhesion is only by 
points, the force applied should not be either too powerful or in the 
manner of a blow. I find a piece of paper, a small feather, or a 
camel-hair brush applied under the water very convenient for the 
purpose. When the point of a floating wedge-shaped piece of ice ig 
brought under water against the corner or side of another floating 
piece, it sticks to it like a leech; if, after a moment, a paper edge be 
brought down upon the place, a very sensible resistance to the rupture 
at that place is felt. If the ice be replaced by like rounded pieces of 
wood or glass, touching under water, nothing of this kind occurs, nor 
any signs of an effect that could by possibility be referred to capillary 
action ; and finally, if two floating pieces of ice have separating forces 
attached to them, as by threads connecting them and two light pen- 
dulums, pulled more or less in opposite directions, then it will be seen 
with what power the ice is held together at the place of regelation, 
when the contact there is either in the flexible or rigid condition, by 
the velocity and force with which the two pieces will separate when 
the adhesion is properly and entirely overcome. 
