This is by the beautiful method of rock-crystal prisms, not the Rochon method of double-image, but by thin wedges cut to given angles.

Their Classification of Man and Beasts.""We look upon the animal in no different light from that of a vegetable, a plant, or a rock-crystal, which forms under the Creative hand, performs its part for the use of man, dissolves and reproduces by its parts another comfort for him.

Closely questioned, the Lieutenant's evidence was as round, complete, and lucid as a Japanese sphere of rock-crystal.

The Thuyère comes down from the Cantal mountains, and as it reaches Entraygues it spreads out over a broad smooth bed of pebbles, its water as clear as rock-crystal; and when the morning sun looks down upon it over the vine-clad hills, it is like something that has been seen in the happiest of dreams.

I have, however, by me as I write, a fragment, formerly clear rock-crystal, so completely fused that between crossed Nicols it behaves as if an amorphous body, save in the very center where a speck of flashing color reveals the remains of molecular symmetry.

It is said that one of the most magnificent diamonds in Europe, which to-day blazes in a king's crown, once lay for months on a stall in a piazza at Rome labelled, "Rock-crystal, price one franc."

CAIRNGORM, a yellowish-brown variety of rock-crystal, so called from being found, among other places, on one of the Scottish Grampians, in Aberdeenshire, so named.