To one ounce of crystallized nitrate of silver, dissolved in one ounce
of concentrated aqua ammonia, add one ounce of gum arabic and six
ounces of soft water. Keep in the dark. Remember to remove all grease
from the hair before applying the dye.
There is danger in some of the patent hair dyes, and hence the
Scientific American offers what is known as the walnut hair dye. The
simplest form is the expressed juice of the bark or shell of green
walnuts. To preserve the juice a little alcohol is commonly added to
it with a few bruised cloves, and the whole digested together, with
occasional agitation, for a week or fortnight, when the clear portion
is decanted, and, if necessary, filtered. Sometimes a little common
salt is added with the same intention. It should be kept in a cool
place. The most convenient way of application is by means of a sponge.