advise everyone interested in hat manufacturing or similar industries to
make a collection of wool and fur fibres, and mount them on microscope
slides so as to form a kind of index collection for reference.

[Illustration: FIG. 15.

1. Natural wool fibre unproofed.

2. Wool fibre showing proof on surface, filling up the cells
and rendering the same dye-proof.

3. Fur fibre from surface of veneered felt, showing dye
deposited in cells and on the surface, bright and lustrous.

4. Wool fibre as in No. 2, with dye deposited on surface of
proof.

5. Section of proofed and veneered body, showing unproofed
surface.

6. Section of proofed body without "veneer."]




LECTURE VIII

MORDANTS: THEIR NATURE AND USE