178 Certain New Derivatives in the Aromatic Series. 



Cachou de Laval. Fusing organic substances, as starch, bran, 

 etc., with Xa^S. 



Hemolin. Action of NaNO., on logwood. 



This list covers the whole territory of the Coal-Tar Colors, and 

 gives representatives of every class of artificial dyes. I uow pass 

 to the original work. It is a pleasure and a privilege to express 

 obligations and gratitude to Professors Charles F. Chandler and 

 Charles E. Colby for their kind encouragement and many favors 

 extended while this thesis was in the process of construction. The 

 creditors have been well chosen by their debtor, who only becomes 

 one of a large number. 



THE PROPOSITIONS which this thesis undertakes to estab- 

 lish are : — 



I, That Fluoren is capable of giving derivatives which will com- 

 pare with the dyes from benzidine, tolidine, and dianisidine. 

 II. That Leuk-Auramine can be used to give very resistant colors. 

 III. That Di-Naphtols increase the strength of dyes as they heighten 



the molecular weight. 

 lY. That Chinoline will give reliable colors. 

 Y. That Schoellkopf's Acid, 1:4:8, gives, as a rule, colors which 



are fast to light. 

 \l. That Bromine is disadvantageous in the Azo-Group. 



The work described in the following pages was undertaken in the 

 hope of making new derivatives of coal-tar which would rival the 

 dyes already in commerce. Many now in common use in the prac- 

 tical world give colors which are fast in some respects, and not 

 easily to be surpassed in their special qualifications. But there are 

 no dyes which combine all the desirable qualities. To be perfect a 

 dye must be able to withstand prolonged exposure in the sunlight, 

 and further, resist washing with all the ordinary household chemicals. 



To give an idea of the state of the field in which the work of this 

 thesis was done, a brief statement of the best three starting-points 

 for azo dyes is given here. 



C,H,XH, 



a. Benzidine, | is used for yellows, blacks, and reds in 



C,H,.NH, 



the cases of the dves — 



