976 Transactions of the American Institute. 



Mass., and Mr. H. Burrows, the skillful superintendent and chemist 

 of these works, will testify any time that all the aniline blacks he pro- 

 duces now are produced by my process, and without a trace of 

 capper or iron. Up to the summer of 1866 the aniline black, which 

 is so useful, and to-day indispensable in calico printing, could not be 

 produced on silk. The oxidizing agent, which is necessary to pro- 

 duce the black color (perfectly harmless to the vegetable fiber), would 

 oxidize the animal fiber. The same color which would be a beauti- 

 ful jet black on cotton would produce nothing but a dull buff on silk. 

 I overcame this difficulty in the following manner : 



It is a known fact, discovered by Schweitzer many years ago, that 

 a solution of metallic copper in ammonia would, under the influence 

 of the oxygen of the air, dissolve cotton as water dissolves sugar. 

 Such a solution of cotton, which is perfectly clear, will, by the action 

 of an acid, abandon again all the cotton it had dissolved in an 

 insoluble form, although very finely divided state. I took a yard of 

 white foulard silk, divided it into two parts ; one part I left intact, 

 the other part I padded in a solution of cotton. After squeezing the 

 same between rollers, I immersed it in a weak solution of acetic acid, 

 then washed the silk thoroughly in water ; none of the brilliancy of 

 the silk had gone, although every, fiber was vegetableized with mole- 

 cules of cotton. I printed the same aniline black color, on a piece 

 of silk, untouched, and a piece of silk vegetableized as described. 

 After aging, the result was a dull buff shade on the ordinary foulard 

 silk, and a beautiful jet black on the vegetableized silk. 



I must now, gentlemen, thank you for your kind attention. 



On motion of Dr. Yan der Weyde, the thanks of the Association 



were tendered to Prof. Chandler and Mr. Paraf for their interesting 



remarks. 



Adjourned. 



