A large number of compounds have been proposed at various times for rendering articles of everyday use more or less impervious to wet. These will now be collected together and arranged under 4 heads, according as they are designed more particularly for felt hats, leather, paper, or textile goods.
(1) The stuff of coarse hat bodies is imbued with drying oil, prepared by boiling 50 parts linseed oil with 1 part each of white-lead, litharge, and umber. The felt to be dried in a stove, and then polished by pumice;
5 or 6 coats of oil are required; the surface is at last varnished. When the hat is inteuded to be stiff, the fabric is to be impregnated, first of all with paste, then stove-dried, cut into the desired shape, and pumiced repeatedly; lastly placed in a hot iron mould, and exposed to strong pressure.