330 
PEOFESSOES TTXDALL AKD HUXLEY OX 
Fig. 3. 
Fig. 4. 
reduced to a transparent lens of the shape and size of the mould in which it h/id lem 
formed. 
This lens was placed in a cylindrical cavity, two inches wide and half an inch deep, 
hollowed out in a piece of boxwood, C, fig. 3, as before ; a fiat plate, D, 
of the wood being placed over the lens, it was submitted to pressure. The 
lens broke as the sphere did, but the fragments attached themselves in 
accordance with then- new conditions, and in less than half a minute the 
mass was taken from the mould a transparent cake of ice. 
The substance was subjected to a stdl severer test. A hemispherical 
cavity was hollowed out in a block of boxwood, and a protuberant hemi- 
sphere was turned upon a second slab of the wood, so that, when the 
protuberance and the cavity were concentric, a distance of a quarter 
of an inch separated the convex surface of the former from the concave 
surface of the latter. Fig. 4 shows the arrangement in section. The 
pins of brass, fixed in the slab AB, and entering suitable apertures in the mould CD, 
served to keep the two surfaces concentric. A lump of clear ice 
was placed in the cavity, the protuberance was brought down 
upon it, and the mould submitted to hydraulic pressure. After a 
short interval, it was taken from the press, and when the upper 
slab was removed, a smooth concave surface of ice was exposed. 
By tapping the conical plug p, this ice was lifted from the cavity, 
the lump having been converted by pressure into a hard transparent 
cup of ice. 
The application of the results here obtained to the “ viscous flow ” of glaciei*s, will 
perhaps be facihtated by the following additional experiments. 
A block of boxwood (A, fig. 5), 4 inches long, 3 wide and 3 deep, had its upper 
surface slightly curved, and a longitudinal groove (shown in dots 
in the figure), an inch wide and an inch deep, worked into it. A 
slab of the wood was prepared, the under surface of which was that 
of a convex cylinder, curved to the same degree as the concave sur- 
face of the former piece. The arrangement is shown in section at B. 
A straight prism of clear ice, 4 inches in length, an inch mde, and 
a little more than an inch in depth, was placed in the groove, and 
the upper slab of boxwood was placed upon it. The mould was 
submitted to hydraulic pressure, as in the former cases ; the prism 
broke as a matter of course, but the quantity of ice being rather more 
than sufiicient to fill the groove, and hence projecting above its edge, 
the pressure brought the fragments together and re-established the continuity of the ice. 
After a few seconds it was taken from the mould, bent as if it had been a plastic mass. 
Three other moulds similar to the last, but of augmenting curvatime, were afterwai’ds 
made use of, the same prism being passed through all of them in succession. At the 
Fig. 5. 
