APPENDIX 
449 
No preliminary treatment of the viscose silk to render it more 
adsorptive is necessary. 
A 50 per cent alcoholic, alkaline solution of turmeric is prepared 
by boiling approximately 20 g. of ground turmeric root with 
50 c.c. of alcohol and adding to the filtered solution an equal 
volume of water and | to i cc. of dilute sodium hydroxide (10 
per cent). The fibers are immersed in this solution which is 
then evaporated on a water bath ^ to a syrupy consistency. The 
fibers are removed and immediately dipped in 95 per cent 
alcohol, pressed between filter paper, dipped in a dilute aqueous 
solution of sulphuric acid, washed with water and dried. The 
transference of the fibers from the hot dye to the alcohol must 
be done quickly as otherwise the turmeric adhering to the fibers 
is removed only with difficulty. Too long an immersion in the 
alcohol tends to remove the adsorbed dye as well as the excess 
dye. 
If the fiber still appears to have any unadsorbed turmeric 
adhering to it (with viscose silk this is easily noted by the lack 
of luster) it can once more be dipped in alcohol and washed with 
water. Any unadsorbed turmeric interferes with the formation 
of the blue color in the boron test. This method as given yields 
a beautiful golden yellow product which was found to be emi¬ 
nently satisfactory. 
Preparation of Wool Impregnated with Zinc Sulphide. — The 
defatted wool is swelled by soaking over night at room temper¬ 
ature, in a I per cent solution or sodium hydroxide. It is then 
washed and dipped 5 or 6 times alternately in solutions of 10 
per cent zinc acetate and 10 per cent sodium sulphide, pressing 
out the excess solution but not washing between dippings. 
After the final dipping, the impregnated wool is washed and 
dried by pressing between filter paper. Zinc sulphide wool fibers 
made in this way are sensitive to 0.001 mg. of copper. The 
sodium sulphide solution should be freshly prepared by passing 
H2S into a solution of NaOH until a portion removed fails to 
^ When preparing or working with fibers impregnated with turmeric all contact 
with “ resistance ” glass vessels or object slides is to be avoided since glass of this 
variety usually contains boron. 
