The room should be close, the chimney, if any, being closed up; the sulphur should burn under the silk all night. The next morning the windows should be opened to let out the smoke and admit the air, which, in summer, will be sufficient to dry the silk; but in winter, as soon as the sulphurous fumes are dissipated, the windows must be shut and a fire kindled in the stove or stoves to dry the silk.
Observe, if the room for sulphuring does not admit of openings sufficient for the dissipation of the sulphuric fumes, the work-people will be in danger of suffocation.
When the sulphur is consumed it leaves a black crust which will light the future sulphur like spirit of wine.
If, in dressing, the silk sticks together, it is not sufficiently dry.
Silk, which has been sulphured, has a rustling, which, for some things, is esteemed; but this would not do for silk to be watered. If silk, which has been sulphured is to be dyed, it must, for many colours, be unsulphured.
Silks for lace, gauze, &c. are neither boiled nor ungummed; silks which are naturally the whitest are the best for those articles. It is sufficient to dip the silks in warm water, and wring them; then sulphur them, afterwards azure them, again wring them, sulphur them a second time, or soak them in soap and water, those for whitening hot enough to bear the hand, adding azure, if necessary, and turning and re-turning the silk in this liquor.
The fine silk of Nankin requires no whitening.
On aluming silk.
We have treated of this before at the commencement of the third chapter, but a few more observations may be useful.
The silk being first well washed and beetled, and the hanks tied loose so that every thread may take alike, should be turned and re-turned in the alum liquor and worked, cooled in it, at intervals, from morning till night, afterwards taken out, beetled, and rinsed.