with which he could detect changes in the fermenting activity, the changes 

 in turn signaUng when more lime or bran should be added or the vat stirred. 



Perhaps early dyers were not aware that indigo and woad contained 

 a common dye principle, indigotin, and that indigotin was present in 

 greater concentration in indigo; however, they gradually realized that 

 woad was definitely the less potent of the two substances. Long after dyers 

 discovered the true value of indigo it was still being used in combination 

 with woad, because it was supposed to promote fermentation and to "render 

 the colour brighter." Regarding the latter, some dyers felt that only with 

 the addition of woad could certain fine blue tones be produced. This notion 

 may have been true, or it may have simply indicated the dyers' lack of skill 

 in working indigo vats to produce these hues. 



Very little woad was grown in the United States. Some was grown in 

 Britain, but most of the woad used here was imported from France and 

 Holland. William Partridge in 1847 remarked that an inferior quality 

 of woad had been grown and marketed by a number of farmers located 

 in the Hartford, Connecticut, area. He felt that the inferior quality was 

 the result of poor processing. Homegrown woad, also mentioned by other 

 dyers of that period, was probably raised on a small scale in various parts 

 of Northeastern United States, since growing conditions were quite suitable 

 for its cultivation. Processing was a far greater problem than growing, 

 for even before it could be used woad required long, complicated fermen- 

 tation and drying procedures. It was sold in the form of 150- to 200-pound 

 bails and also in balls that resembled clods of dried earth interlaced with 

 plant fibers. 



Although its use continued throughout the 19th century, its importance 

 diminished gradually until the end of the century when it was practically 

 obsolete. Woad is last mentioned as a dye ingredient in early 20th-century 

 English dye literature; by that time its use was certainly very limited. 



CHEMIC (a popular name for indigo sulfate) or Saxon blue 



Chemic, frequently mentioned by 19th-century dyers, is a product of 

 the treatment of powdered indigo with concentrated sulfuric acid. Its 

 properties were totally different from those of indigo, for chemic had poor 

 fastness to light and washing, contrasted to the indigo vat dye's excellent 

 colorfastness. It was applied to some silks and coarse wools and even cotton 

 because of its relatively simple application (mordanting and immersion 

 of cloth in dye solution) and characteristic, though short-lived, blue 

 coloring. 



According to one story chemic was discovered by a certain Mr. Seidelman 

 who lived in Altenburg, Saxony, during the mid- 18th century. He com- 

 bined sulfuric acid with powdered indigo, which made a black paste. This 



19 



