linseed oil. The leather, after this process, is soaked in petroleum or
carbon bisulphide containing a little India-rubber solution, and is finally
washed with petroleum benzoline. Should the mixture be found to be too
thick, it is thinned down with benzoline spirit until it is about the
consistency of molasses at the ordinary temperature. The leather so
prepared is not liable to stretch, and can be joined in the usual way by
copper riveting, or the ends can be sewn. A good material for smaller
belts, and for strings and bands for connecting larger ones, is that
recently patented by Vornberger, in which the gut of cattle is the basis.
After careful cleansing, the gut is split up into strands, and treated with
a bath of pearlash water for several days. The strands are then twisted
together, and after being dipped in a solution of Condy's fluid, are dried.
They are then sulphured in a wooden box for twenty-four hours, after which
the twisting can be completed. They are by this process rendered pliable,
and can be used in this state for stitching the leather ends of larger
belts, or can be stiffened by plunging them into a bath of isinglass and
white wine vinegar. After drying they are susceptible of a fine polish,
emery cloth being usually employed, and the final "finish" is given to the
material with gum arabic and oil.

Canvas and woven fabrics, coated with India-rubber, are also now being used
for driving belts and for covering machine rollers. As this material can be
made in one piece, without the necessity of a joint, it is uniform in
strength, and is recommended as a substitute for leather belts requiring
joints. A patented material of this description is due to Zingler, who
boils the canvas or similar woven fabric under pressure in a solution of
tungstate of soda for three hours. It is then transferred to a bath of
acetate of lead solution, and drained, dried, and stretched. When in this
condition it is coated, by means of a spreading machine, with repeated
layers of a composition consisting of India-rubber, antimony sulphide,