224

SILK.

sion the dark stains upon the silk, and the blackness of the extract taken out of it bydistilled water.

6. That the dressing applied to the webs is not simply a decoction of rice, becomesvery manifest, by comparing the'incinerated residuum of rice with the incinerated re-,siduum of the extract of the said Corahs. I find that 100 grains of rice, incinerated ina platinum capsule, leave only about one fifth of a grain, or 1 in 500 of incombustiblematter, which is chiefly silicious sand; whereas, when 100 grains of an average extractof several of these Corahs were similarly incinerated, they left fully 17 parts of incom-bustible matter. This consisted chiefly of alumina or earth of clay, with silica, potassa,and a little common or culinary salt. (Has the clay been added, as is done in Man-chester, to give apparent substance to the thin silk web ?)

From the above elaborate course of experiments, which occupied me almost con-stantly during a period of four weeks, I was fully warranted to conclude that the dam-age of the said goods had been occasioned by the vile dressing which, had been put intothem in India ; which, as I have said, under Jhe influence of heat and air, had causedthem to become more or less mildewed, in proportion to their original dampness when,packed at Calcutta , and to the accidental ingress of atmospheric air into the cases du-ring the voyage from Calcutta to London .

The following is the list of Corahs which I chemically examined :—

1 and 2, per Colonist, from Calcutta , 2 pieces, sound.—These two pieces had beendressed with a sweet viscid matter, like jaggery or goor (molassy sugar), mixed withthe rice water. This extract contained no urine, but emitted a smell of caramel orburned sugar, when ignited. It amounted to 270 grains in the one, and 370 in theother.

3, ditto, 1 piece, mildewed, 1st degree.—This piece had been dressed like No. 5, andcontained no trace of urine. It afforded 400 grains of a most deliquescent sweetishglutinous matter.

4, ditto, 1 piece, mildewed, 1st degree, as No. 3.

5, ditto, 1 piece, mildewed, 3d degree.—This piece contained no trace of urine, but >'

afforded 210 grains of a light brown extract, being rice water, mixed with somethin?like jaggery. .

6, ditto, 1 piece, 3d degree, mildewed.—This piece afforded evidence of urine inby test of carbonate of ammonia. The extract amounted to 320. grains.

8, ditto, 2 pieces, damaged in the - 3d degree.—The total weight of one of these P ie "

ces, after exposure to air,.was 4,610 grains, and it lost 440 grains by drying. The totweight of the other was 4,950 grains, and it lost 320 grains by drying. The weightextract was, in one piece, 210 grains; and both pieces contained abundant traces

ital

of

of

id

urine, as well as of potash. These constituents, along with the rice water, accounte 1sufficiently for the great damage of these two pieces by .mildew.

10, ditto, 2 pieces, .sound.—These contained no urea. Each afforded from 300 t500 grains of a light brown vegetable extract. r

12, ditto, ,2 pieces.—The extract in the one amounted to 222 grains, and in the otnto 330. Both contained urea, and had, therefore, been imbued with urine.

14, ditto, 2 pieces, mildewed, 3d degree.—There was no urea in the extractsthese two pieces; but they afforded, the one 300 grains of extract, and the otherBut this extract was a saccharine molassy matter, impossible to dry over a steam

from

750-

heat-

_L»ul uiia CAiiacu was a saucitcuiiiic muiasoy iiiauci) xiii^vsBi vie tv uiy vvci a on-**— , _

The same quantity as the last, if dried by stronger means, would have weighed pr°bly 600 grains. Its extraordinary deliquescence kept the pieces very moist, and theby caused the mildewing of them. With the saccharine matter, four per cent, ol cnary salt was mixed in one of these extracts. . gj

16, ditto, 2 pieces, 3d degree of mildew.—The extract, about 200 grains, contaabundant evidence of urea, and, consequently of urine. on e

18, ditto, 2 pieces, sound.—Both these contained some traces ol urea; but ttLe beettyielded only 102 grains of extract, and the other 370 grains. They must havewell screened from the air to have resisted the action of the urine. 320

20, ditto, 2 pieces, damaged, 1st degree.—No urea. The extract of the one ' v ? ar ; n egrains; of the other piece 380; and it had a light brown color, being a saccmucilage. 2l0 in

22, ditto, 2 pieces, 3d degree mildew.—200 grains of extract in the one, an ^the other: they contained urea. iso trraia p

24, 2 pieces, 3d degree of mildew.—310 grains of extract in the one, and 1 =

in the other. Both were impregnated with urea, and consequently with urine. j ie mica'Having in the preceding report demonstrated, by the clearest processes 01 c ,j ve de-research, that the above mildewed Corahs had been damaged by the fermen ® a ted,composition of the dressing paste with which they had been so abundantly imp to

I would recommend the importers of such goods to cause the whole of the r up-be washed out of them, and the pieces to be thoroughly dried, before being P