61. - The Cloth used for Wheels is usually thick woollen cloth such as that for white great coats, and the blankets of printing machines, felted cloths are likewise used. Sometimes the cloth or felt is simply glued around the edge or upon the face of the wooden wheels precisely the same as in buff wheels, and is employed for similar purposes.

62. - Opticians' Cloth Tools, consist of a circular piece of cloth cemented by means of pitch upon the surface of one of their brass concave or convex tools of the required curvature, the cloth if new is seared with a hot iron to remove the nap before it is cemented down.

Sometimes the opticians' metal tools are covered with a broad strip of thick silk or lute string, which is folded around the edges and cemented at the back of the tool. The cloth and silk tools are always used with putty powder. See the articles Lenses Chap. XXXIII. Section 4.

63. - The Lapidaries Cloth Mill is a face wheel having an annular surface about two inches wide, there is first a center of wood of about 6 inches diameter, then a spiral coil of wide list or cloth which is wound up closely until the diameter of the cloth becomes about 10 inches. The cloth is secured partly by tacks driven first into the wood centers, and then by small nails driven into the plate of wood that forms the back, and the outer coil is nailed around the edge of the principal disk, so that the whole forms an annular face with a loose pliant surface, the top of which is dressed level with an iron heated to a dull red.

The list or selvedge of woollen cloth is commonly used, and as this is thicker on one edge than the other, it is the practice of many lapidaries to roll on two coils at once by aid of two individuals, the thick edge of the one coil being downward and of the other upwards; this mode equalizes the tension and prevents the list gathering up as a cone - and in this case it is only usual to nail the list at the beginning and ending of the coil.

The list wheel is employed generally with pumice-stone and water, and from its elasticity it yields admirably to the curved surface of shells and stones; it is also employed for plane surfaces on many soft substances, as explained under the article Alabaster in this Catalogue. 64. - Ivory Workers' List Wheels consist of 10 to 20 circular pieces of cloth screwed fast between two disks of wood about 2 or 3 inches smaller than the cloth, which therefore forms a pliant edge projecting an inch or upwards beyond the wood, and which is well adapted to the curvilinear surface of umbrella or parasol handles, and many such works - the wheel is fed with Trent sand, loam or chalk, or it is better to have one wheel for each of these substances. See Ivory.