Extracts
Dec
23rd 1921
The weighting on silk is determined in an indirect manner. The amount of pure silk is estimated by Kjeldahl's method for nitrogen and the weighting found by difference.
About 2 gms of silk are weighed out and placed in a long-necked flask. A bead of mercury is added, and the material thoroughly wetted out with 25 ccs of concentrated sulphuric acid. This is heated gently till gases are freely evolved, when 10 gms Potassium Sulphate are added to raise boiling point and thereby assist the digestion of the silk. When the solution is quite clean, it is allowed to cool. When it is quite cold, a little water is poured down the sides of the flask and the solid mass which has been formed is dissolved and the resulting solution carefully poured into a flat bottomed flask. 25 ccs of 4% Potassium Sulphide are added to precipitate the mercury...
The weighting on silk is determined in an indirect manner. The amount of pure silk is estimated by Kjeldahl's method for nitrogen and the weighting found by difference.
About 2 gms of silk are weighed out and placed in a long-necked flask. A bead of mercury is added, and the material thoroughly wetted out with 25 ccs of concentrated sulphuric acid. This is heated gently till gases are freely evolved, when 10 gms Potassium Sulphate are added to raise boiling point and thereby assist the digestion of the silk. When the solution is quite clean, it is allowed to cool. When it is quite cold, a little water is poured down the sides of the flask and the solid mass which has been formed is dissolved and the resulting solution carefully poured into a flat bottomed flask. 25 ccs of 4% Potassium Sulphide are added to precipitate the mercury...
See Also:
Historical
developments
Fashion
through the ages
Turkey
red: history
Snippet
from Mr C W King, Courtaulds, Bocking 1920.
