50 
POPULAR SCIENCE REVIEW. 
Tyndall. At a Friday evening meeting at the Boyal Institution, 
in June, 1850, Mr. Faraday stated that when two fragments of 
melting ice are placed together, they freeze at their points of 
contact. This fact, subsequently termed regulation , recalled 
glaciers to Professor Tyndall, and from glacier ice to glacier 
snow was a rapid transition. If two pieces of ice freeze 
together, may not innumerable granules of snow freeze into 
a solid mass ? The probable formation of the neve and 
the glacier were thus swiftly suggested. In his own words, 
Professor Tyndall says 
Snow was in the yard of the Royal Institution at the time ; stuffing a 
quantity of it into one of the steel moulds which I had previously employed 
to demonstrate the influence of pressure on magnetic phenomena, I squeezed 
the snow, and had the pleasure of seeing it turn out from the mould as a 
cylinder of translucent ice. 
A section of the identical mould used in this experiment is 
given in fig. 4. A b is the solid base of the mould ; c d e e 
a hollow cylinder let into the base ; 
p is the solid plug used to com- 
press the snow. When sufficiently 
squeezed, the bottom a b is removed, 
and the cylinder of ice is pushed 
out by the plug. 
But what is true of snow is 
equally true of fragments of melt- 
ing ice. These can be moulded 
into any shape by pressure, just 
as the snow was moulded. The 
following beautiful experiment illus- 
trates this fact : — Placing a quantity 
of broken ice in a boxwood mould 
(fig. 5), shaped like a cup and ball, 
and powerfully squeezing the mass, 
the fragments are crushed ; but by 
this very act are brought into close 
contact ; regelation occurs at innu- 
merable places, and finally on re- 
lieving the pressure a perfect cup of 
clear ice can be turned out of the 
mould. Filling another mould in 
the same way, a circular disk of 
and by means of the mould, shown 
enlarged in fig. 4, a number of little ice cylinders can be 
produced. Piling the cylinders one over the other on the 
disk, and placing the cup on the top, a claret-glass of trans- 
parent ice is obtained (see fig. 7) ; the parts, shown separately 
Fro. 4. 
ice can be formed 
