There is no hair dye which produces a durable coloration; the color becomes gradually weaker in the course of time. Here are some typical formulas in which a mordant is employed:

I

Nitrate of silver..... 0.5 ounce

Distilled water.....     3 ounces

Mordant:

Sulphuret of potassium ............ 0.5 ounce

Distilled water.....     3 ounces

II

(a) Nitrate of silver (crystal) ............. 1.5 ounces

Distilled water.....12 ounces

Ammonia water sufficient to make a clear solution. Dissolve the nitrate of silver in the water and add the ammonia water until the precipitate is redissolved.

(b) Pyrogallic acid.....     2 drachms

Gallic acid.........     2 drachms

Cologne water......     2 ounces

Distilled water.....     4 ounces

III

Nitrate of silver..... 20 grains

Sulphate of copper. . 2 grains Ammonia, quantity sufficient. Dissolve the salts in 0.5 ounce of water and add ammonia until the precipitate which is formed is redissolved. Then make up to 1 ounce with water. Apply to the hair with a brush. This solution slowly gives a brown shade. For darker shades, apply a second solution, composed of:

IV

Yellow sulphide ammonium.........     2 drachms

Solution of ammonia    1 drachm

Distilled water.....     1 ounce

Black Hair Dye without Silver

V.—Pyrogallic acid .... 3.5 parts

Citric acid........ 0.3 parts

Boro-glycerine. ... 11 parts

Water............ 100 parts

If the dye does not impart the desired intensity of color, the amount of pyrogallic acid may be increased. The wash is applied evenings, followed in the morning by a weak ammoniacal wash.

One Bottle Preparation

VI.—Nitrateof copper .. 360 grains Nitrate of silver. . . 7 ounces Distilled water. ... 60 ounces Water of ammonia, a sufficiency. Dissolve the salts in the water and add the water of ammonia carefully until the precipitate is all redissolved. This solution, properly applied, is said to produce a very black color; a lighter shade is secured by diluting the solution. Copper sulphate may be used instead of the nitrate.