A remarkable feature of this process is that the starch carries nearly all the impurities down with itself to the bottom of the wash-basin, and becomes soiled, while the benzene takes up every little of them, and can, therefore, after settling, be poured off from the starch sediment, and can be used several times before it needs to be purified or eventually becomes unfit for use.
In using benzene, which is a highly combustible substance, the utmost precaution must be observed that no open flame or fire be in the work-room, neither open lamps nor a fire in the stove burning. Even doors leading to adjoining rooms, where lights or fires are burning, ought to be kept closed while working with benzene, because the benzene vapors, which may be carried to the flame by a draft of air, would inevitably ignite and cause an explosion and fire. Occurrences of this kind have been not unfrequently observed.
Feathers which have been cleaned by this process, as well as new feathers, may be dyed by the following process.
DYEING IN THE COLD WAY.
This process is a real dyeing process, as well as a renovating process, both, however, to a limited extent, inasmuch as it can be applied only to white feathers or to such as are dyed with light and medium shades of certain colors which are to be freshened up; but it does not answer for dark colors. It is, however, extremely simple and easy to execute; besides, almost instantaneous, and therefore of great utility where rapid work is required, because it leaves the feathers perfectly in shape, like the benzene washing process, and does not affect the curling of the feather, if there is such. Old feathers which were already dyed cream, rose, salmon, light blue, light gray, light green, sea green, golden yellow, heliotrope or beige, can be redyed in the same colors, but must previously be washed with benzene; new white feathers do not require such washing.
For this method of dyeing, aniline dyestuffs soluble in alcohol are used, viz.: for
Operate as follows: Fill a white basin with a sufficient quantity of alcohol to completely wet the feathers in it; add, according to shade, a smaller or greater quantity of the clear alcoholic solution of the required dyestuff, or mixture of dyestuffs, pass the feathers singly, without previously wetting them, three or four times through the alcohol bath; then press them out between clean muslin, put a few handfuls of sifted potato starch upon a clean sheet of paper, and rub the feathers with it until thoroughly dry; finally, shake out the starch.