62 NOTE ON REGELATION- 
investigation, and therefore has not sunk in value among the three 
investigations given. 
Dr. Tyndall added to one of his papers*, a note of mine “On ice 
of irregular fusibility ” indicating a cause for the difference observed 
in this respect in different parts of the same piece of ice. The view 
there taken was strongly confirmed by the effects which occurred in 
the jar of water at constant temperature described in the beginning 
of the preceding pages, where, though a thawing process was set up, 
it was so slow as not dissolve a cubic inch of ice in six or seven 
days. The blocks retained entirely under water for several days, 
became so dissected at the surfaces as to develop 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 norelation 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. 
AppENpuM :—The following method 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 an inch thick; render the edges 
round, and the upper surface of each piece convex, by holding it 
against the inside of a warm sancepan cover, or in any other way. 
When two of these pieces are put into the water they will 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, or 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 ofa plate of ice, the latter may be entirely 
submerged, and the tendency to approximation from capilliary action 
converted into a force of separation. When two or more of such 
floating 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 adhesion. When five or six pieces are grouped in a 
contorted shape, as an S, and one end piece be moved carefully, all 
will move with it rigidly ; or, if the force be enough to break through 
# Philosophical Transactions, 1858, p. 228, 
