Willesden Fabrics1 are vegetable substances which have been treated with certain compounds of copper and ammonia, the effect of which is to coat and impregnate them with cupro-cellulose, a varnish-like substance which not only protects the surfaces but adds strength to the fibres by cementing them together.

This enables the fibre to resist the weather, and renders it less liable to catch fire. Ropes, cordage, and netting are treated in this way, but the fabrics most useful to the builder are the Willesden paper and canvas.

Willesden Paper is of three classes.

Unwelded (marked WPG 1), or "one ply" paper, is made 54 inches wide, of indefinite length, and is chiefly used for packing.

Welded, which consists of several "plys" or thicknesses of paper formed (while they are still gelatinised by the action of the cupro-ammonia solution) into a compact sheet or thickness.

The different classes of this paper are known as follows. They are all made in brown and neutral green colours.

Willesden 2 ply (WPG 2) is in continuous lengths, 54 inches wide. It is useful for underlining slates, tiles, internal decorations, floors, damp walls, leaky roofs, etc.

Willesden 4 ply (WPG 4) is weatherproof and strong, a bad conductor of heat, free from condensation, does not easily catch fire, does not require painting, and is said to be proof against the white ant; it is useful for roofing, sides of huts, etc.

The relative covering powers of this and good galvanised iron are stated by the manufacturers as follows: -

Willesden paper. WPG 4

Galvanised iron.

Weight of one square in lbs. ....

. 15 to 18

103 to 2S0

Area covered by one ton in squares . Willesden 8 ply may be used as panel board.....

. 125 to 150

8 to 22

Willesden Canvas is prepared in a similar way to the paper, and can be used with advantage for most purposes to which canvas is applied, including making hose.

1 Patentees' Circulars.

Wire Wove Roofing

Wire Wove Roofing consists of a semi-transparent substance, apparently some preparation of linseed oil upon a basis of very fine wire mesh. It is said to be waterproof, tough, elastic, strong, and not affected by atmospheric changes, and is made in sheets of 10 feet by 4 feet and of 10 feet by 2 feet

Emery

Emery Cloth,1 consisting of ground emery of different degrees of fineness attached to calico by glue, is used for finishing and polishing metal surfaces.

Emery Paper is not much used for builder's work.

Glass Cloth and Glass Paper are made respectively from calico and paper coated with ground glass, and are used for producing a smooth surface on wood or for rubbing down painted surfaces.

Silicate Cotton

Silicate Cottonl or Slag Wood is a glasslike fibre blown from blast furnace slag. It is incombustible, vermin-proof, and very light, one ton covering 1800 square feet 1 inch thick, and is therefore useful for making floors and ceilings sound and fireproof.