soft water should be used for
boiling-off since calcareous impurities are liable to mar the lustre of
the silk.

The silk is now rinsed in weak soda solution and wrung. In this
condition it is suitable for being dyed, but if it is to be bleached,
the hanks are tied up loosely with smooth tape, put into coarse linen
bags to prevent the silk becoming entangled, and boiled again in soap
solution which is half as strong as that used in the first operation.
The hanks are now taken out, rinsed in a weak soda solution, washed in
water and wrung.

The actual bleaching of silk is usually effected by stoving as in the
case of wool, with this difference, that the operation is repeated
several times and blueing or tinting with other colours is effected
after bleaching. Silk may also be bleached with peroxide of hydrogen,
but this method is only used for certain qualities of spun silk and for
tussore.

_Ornamental feathers_ are best bleached by steeping in peroxide of
hydrogen, rendered slightly alkaline by the addition of ammonia. The
same treatment is applied to the bleaching of _ivory_. If peroxide of
hydrogen could be prepared at a moderate cost, it would doubtless find
a much more extensive application in bleaching, since it combines
efficiency with safety, and gives good results with both vegetable and
animal substances. (E. K.)

FOOTNOTES:

[1] Besides being used for cotton goods, plate singeing is also
employed for certain classes of worsted goods (alpacas, bunting,
&c.), and for most union goods (cotton warp and worsted weft).

[2] A machine working on this principle has been constructed by F.
Binder, and the makers of the machine (Messrs Mather & Platt, Ltd.)
claim that it does better service than the machines constructed on
the older principle.

BLEAK, or BLICK (_Alburnus lucidus_), a small fish of the Cyprinid
family, allied to the bream and the minnow, but with a more elongate
body, resembling a sardine. It is found in European streams, and is
caught by anglers, being also a favourite in aquariums. The well-known
and important industry of "Essence Orientale" and artificial pearls,
carried on in France and Germany with the crystalline silvery colouring
matter of the bleak, was introduced from China about the middle of the
17th century.

BLEEK, FRIEDRICH (1793-1859), German Biblical scholar, was born on the
4th of July 1793, at Ahrensbok, in Holstein, a vi