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| 922 SILK. 
names of Persian, sarsnet, gros de Naples, du- 
capes, &c., of which the two first are of flimsy 
texture, and the two last are made of stouter 
and harder thrown organzine. Satin is a twill 
| of a peculiar description, the soft and lustrous 
face of which is given by keeping a large propor- 
tion of the threads of the warp visible. When 
first taken out of the loom, satins are somewhat 
flossy or rough ; and they are dressed by being, 
rolled on heated cylinders, which operation gives 
them their brilliant lustre. Crape is a light and 
transparent article of plain weaving; Levantine, 
a stout, close-made, and twilled silk. Gros des 
Indes is formed by using different shuttles, with 
threads of various substances for the shoot. 
The process of watering silk, which gives its sur- 
face a peculiar wavy appearance, is performed by 
passing two pieces of silk, placed lengthwise, one 
on the other, between two metallic rollers ; the 
different parts are thus subjected to different 
degrees of pressure, from which the wavy ap- 
pearance results. Silk is embossed by passing 
the plain stuff between rollers, the surfaces of 
which contain the desired pattern, on one cylin- 
der raised, and on the other sunk, so that the 
eminences of the one coincide with the depres- 
sions in the other. Silk also enters into the 
composition of several mixed fabrics, the most 
common of which is bombasin, a twilled manu- 
facture, having its warp of silk and its shoot of 
worsted. Poplins and lustres are plain woven 
goods, with a larger proportion of silk than bom- 
| basins. 
The annual value of the silk manufactures 
in England is stated at £14,000,000. The 
raw silk is imported to the amount of above 
4,000,000 pounds annually, of which 1,500,000 
pounds are from Bengal. In 1824, the high 
duty on raw silk imported was abandoned for 
one merely nominal; that on thrown silk was 
reduced nearly one half, and the admission of 
foreign manufactured goods was rendered legal, 
after July 5, 1826. In the five years preceding 
this change, the importation of raw and thrown 
silk had amounted to 10,925,646 pounds; in the 
five years succeeding, the total amount of the 
importation was 18,582,213 pounds. The admis- 
sion of foreign manufactured silks has also led 
to a great improvement in the quality of the 
domestic manufactures. The value of manufac- 
tured silks exported from France in 1824, was 
100,000,000 francs. Italy supplies England and 
France with a large quantity of raw silk. Some 
attention has recently been paid in the United 
States to the rearing of the silk-worm; great 
numbers of mulberry trees have been planted in 
different parts of the Union, and attempts have 
been made to introduce the manufacture of 
| silks in the country. Several experiments have 
been made also as to the producing of silk in 
England ; but hitherto they have been very dis- 
couraging. 
SILK COTTON TREE. See Bompax. 
SILPHIUM. 
SILK-TREE. The Acacia Julibrissin. 
the article Acactra. 
SILKWORM (Bombyx mort). This seemingly 
insignificant insect has now become one of the 
most important to man of all domestic animals. 
It was originally a native of China, and the 
neighbouring parts of Asia, and was there bred 
and domesticated for a long time before it was 
known in Europe. Now, the manufacture of 
silk is one of the most important sources of 
wealth to many parts of that continent. At 
first, silk stuffs were sold for their weight in 
gold; but they are now comparatively cheap. 
The silk-worm is a caterpillar, which, in due 
time, undergoes its metamorphoses, and becomes 
a moth, like others of the genus. 
for the first ten days, the colour of the worm is 
blackish or obscure. 
skin at stated periods, and turns whitish or blu- 
ish, and, when ready to spin, becomes yellow. 
It is covered with scattering hairs, and has a little 
fleshy tubercle on the upper part of the last ring. 
It feeds on the mulberry. Before spinning, it 
See 
fasts for thirty-six hours, voids all its excre- | 
ments, becomes soft and flaccid, and seeks a 
suitable place for the construction of its coccoon. 
Two or three days are occupied in this work, | 
and the thread is stated by Count Dandolo to be | 
sometimes 625 yards in length. The worm then | 
changes to a chrysalis, and, after remaining | 
twenty days, the moth comes out, forcing its 
way through the coccoon. The males first appear, | 
and are very brisk in their motions, but do not | 
They live but a | 
fly, at least in cold climates. 
few days, and the females perish also as soon as 
they have deposited their eggs. 
rearing of silk-worms is a distinct art, and re- 
quires peculiar attention. 
variety of maladies. 
acquired reputation for their production. These 
are packed like grain, and are chosen much in 
the same manner. The eggs are in many places 
hatched by the heat of the human body. The 
silk is contained, in the form of a fluid, resem- 
bling varnish, in long cylindrical sacks, many 
times the length of the animal, and capable of 
being unfolded by immersion in water. This fluid 
is easily forced out, and advantage is sometimes 
taken of this circumstance to procure threads 
much coarser than usual, which are extremely 
strong, and impermeable to water. 
SILPHIUM. A genus of hardy, perennial- 
rooted, yellow-flowered, herbaceous, North-A meri- 
can plants, of the sunflower division of the com- 
posite order. About 15 species, varying in height 
from 23 to 14 feet, and blooming from about the 
end of summer till near the beginning of winter, 
have been introduced to Britain. They are 
sometimes popularly called bastard chrysanthe- 
At birth, and | 
As it grows, it casts its | 
The eggs are | 
attached, often to the number of five hundred, | 
or more, by means of a gummy substance, and | 
hatch in the ensuing spring. The successful — 
They are subject toa | 
In many places, it is usual | 
to import the eggs from some district that has — 
=t 
