448 [Assembly 



tablishments large, produce of these great ; and tliey have 

 arrived at the greatest degree of perfection, especially in 

 woolens, silks, &c.; and, of course, the best coloring matters for 

 these. The French, it is generally allowed, excel in dyes. They 

 are considered among the best chemists of the world ; this gives 

 them great advantages in investigating colors ; the best materials 

 for making these bright and durable. Fourcroy, Bergmann, 

 Berthollet, Chaptal, and many others, stand high as chemists, 

 and in experiments made upon dyes. This, with some other 

 matters, has given the French products, in which the coloring 

 material is used, such great reputation in the world. In giving 

 woolen and silk the blue color, they make use of indigo mostly, 

 although, sometimes, they use several other things with it, ac- 

 cording to the shade of blue, the material to be colored, the con- 

 veniences for performing the work, vats, steeping, washing, air- 

 ing, &c. — the time used in these various operations. The work- 

 men and laborers do not always work as they are told, which 

 affects the color much, and immediately this must be corrected at 

 once, or counteracted by other influences. 



The French chemist sees if any thing has gone wrong and he 

 sets himself to work without delay to correct it, and such is his 

 acuteness and skill in the art, that he generally succeeds. In 

 Germany there are also some good chemists and dyers. The 

 Prussian blue stood high once, it ii not much used though now. 

 Dr. Bancroft, an English gentleman who stands high as a chemi- 

 cal experimenter in colors, made considerable improvements in 

 Prussian blue. By his method it was made bright and deep, and 

 not so subject to change and show different shades, still it was 

 apt to show creases, dust and change in the seams to a whitish 

 color by wear and use — the least touch of alkali made an ugly 

 spot. The Saxon blue is considered an excellent blue; the color 

 is formed with indigo and dissolved in sulphuric acid; this is ac- 

 cording to the French witli some changes in detail. It is some- 

 times called the chemical blue of Poener, as he gave the directions 

 as chemist. It has been said, and correctly, that indigo was an 

 exhauster of soil, and therefore it was hoped its cultivation would 

 be entirely dropped. It is not here thought so; other plants are 

 exhausters too; manure is used to restore the exhaustion, and it 



