from The Century Dictionary.
- noun In chem., a salt of hydrosulphurous acid, now called hvposulphurous acid (H2S2O4).
from the GNU version of the Collaborative International Dictionary of English.
- noun (Chem.), rare A saline compound of hydrosulphurous acid and a base.
from Wiktionary, Creative Commons Attribution/Share-Alike License.
- noun Alternative spelling of
Sorry, no etymologies found.
It has many advantages over the hydrosulphite vat, as it is not nearly so much affected by changes of temperature and weather.
If yarn is streaky, take 10 gallons of water at 120°F., 1 oz. of hydrosulphite powder, 2 fluid ozs. liquid ammonia fort. 880, and let yarn lie in same for 60 minutes.
If the hydrosulphite be weighed beforehand and the stock of the same be kept free from damp air, or great heat, for future vats the hydrometer can be dispensed with; it is simply weighed out and added slowly to the water.
It is a good thing to have hydrosulphite slightly in excess as this prevents premature oxidization; too much will strip off the indigo white already deposited on the yarn.
Next take 5 pints water, add hydrosulphite slowly, stirring gently until a reading of 1100 is shown (SG 1.1) on the hydrometer.
To the saucepan containing the indigo (100 per cent) add 7 fluid ozs. of the caustic soda solution, then gradually add 3-1/2 pints of hydrosulphite solution, stirring gently for 15 to 20 minutes.
Between dips add Stock Solution as required, if the vat goes blue and turbid add 3 to 4 fluid ozs. of hydrosulphite and warm up to 140°F. and wait 30 minutes.
If added too quickly the hydrosulphite will cake, fall to the bottom and be difficult to dissolve.
Add 3 ozs. of hydrosulphite solution stirring carefully, let it stand for 20 minutes; this renders harmless any undissolved oxygen.
If dark spots show, this indicates undissolved indigo, therefore gradually add hydrosulphite solution (2-3 fluid ozs.).