Polytechnic Association. 973 



alone, and 90,000 lbs. of iodine are used in effecting the substitution ; 

 and yet it is an industry which has started since 18G0. 



A word with regard to the carbolic acid colors. The carbolic acid 

 is obtained by treating the dead oil with an alkali. This furnishes a 

 number of coloring matters. Carbolic acid is C 6 H 6 O ; or it is the 

 oxide of benzole, which is C 6 H 6 . Treating carbolic acid with nitric acid, 

 we produce picric acid, C 6 H 8 (N0 2 ) 3 0. Picric acid is a substantive dye 

 for silk and wool, uniting with them without any mordant. Treating 

 picric acid with the cyanide of potassium, an acid is produced which 

 gives beautiful garnet colors on silk and wool. By treating carbolic 

 acid with soda and the oxide of rnercmy, it is converted into rosolic 

 acid, which produces various shades of orange, and is used for color- 

 ing house paper. Treating this with ammonia, it produces a scarlet 

 tint. The intimate connection existing between the rosolic acid and 

 the aniline colors is shown by the fact that, by treating rose aniline 

 with nitrous acid, the same result is obtained. From this orange red 

 of rosolic acid can be produeed a deep blue color by the action of 

 aniline. 



There is a series of naphthaline colors, but they are not found to 

 be fast, and I will therefore pass them by. 



"When coal oil is distilled, and twenty-five or thirty per cent of 

 volatile products are removed, the last portion of the distillate is a solid 

 crystalline hydro-carbon, called anthracene. Recently, from this, there 

 has been artificially produced the coloring matter of madder. The 

 colors from aniline had proved brilliant and durable for silk and wool, 

 but not so well suited for cotton fabrics. It is now a question whether 

 the colors from anthracene will supply this want ; whether they will 

 be found to be permanent. I have here specimens of calicos printed 

 by these colors. As I am not practically familiar with the use of 

 these colors, I ask leave to introduce to you my friend, Mr. Alfred 

 Paraf, a distinguished chemist, who was a pupil of Schutzenberger, 

 of Paris, and who has made the chemistry of dyeing and calico-print- 

 ing his specialty for many years. 



Mr. Alfred Paraf addressed the Association as follows: 



Mr. President and Gentlemen : 



There is very little for me to say on the history of the production 

 and manufacture of the aniline colors, after the beautiful manner in 

 which it has been just presented to you by Prof. Chandler. At his 

 request, however, I take great pleasure in explaining to you their 

 practical application on textile fabrics ; but as my time is limited, I 



