1892.] 



NEW YORK ACADEMY OF SCIENCES. 



157 



The Natural Dyes as Applied to Wool. 



BY H. T. VULTE AND D. W. WARD. 



The work described in this brief memoir was undertaken some 

 five years a.i^o, and frorxi causes unseen at that time the publication 

 has been delayed until the present. 



As originally designed, the work was merely the preparation of 

 a large series of samples of wool dyed with various natural dye- 

 stuffs and common mordants as an exhibit of this branch of the 

 dyer's art now rapidly going out of use. 



During the prosecution of the work it was seen that a valuable 

 comparative method of testing these dyes might be evolved from 

 the facts as recorded in the results of these tests. 



The samples were prepared from pieces of woollen flannel of known 

 purity weighing ten grams each, washed, mordanted in the proper 

 baths, washed again, and dyed in a bath of the dye carefully pre- 

 pared, the conditions differing with the various dyestulfs. 



225 samples were made, with 5 mordants, the list including the 

 following dyestufifs: — 



Brazil-wood, 



Peach-wood, 



Lima-wood, 



Bar-wood, 



Sapan-wood, 



Cam-wood, 



Hypernic, 



Cudbear, 



Cochineal, 



Madder, 



Anatto, 



Lac, 



Catechu, 



Quercitron, 



Barberry root, 



Sumach, 



Saffron, 



Weld, 



Fustic, 



Turmeric, 



Persian berries. 



Logwood, 



Tannin, 



The method proposed for testing or valuation of a dyestufi" is 

 briefly as follows: — 



For instance, logwood : Ten grams of flannel are mordanted with 

 alumina sulphate for one hour at 212° F., then cooled, washed, and 

 divided in two equal parts; one part is dyed in a 10 per cent, bath 

 of standard chips for one hour at 212° F. and the other part in a 

 10 per cent, bath of the logwood to be tested under the same con- 

 ditions. The two pieces are finally removed from their respective 

 baths, dried, and compared as to shade. It is well to have a few 

 samples of 1, 2^, and 5 per cent, standard dye for comparison. 

 With a little practice the shade may easily be matched within 1 

 per cent. It is best always to choose the brilliant shades for com- 

 parison. I have had no difficulty in keeping standard samples, 

 provided they are protected from strong sunlight. 



The following formuke used in these tests will be found inter- 



