10 Trans. Acad. Sci. of St. Louis 



(liffionlt to ostalilish. After many efTorts Graobe and 

 Lioborniann in 18G8 recoKnizod that alizarine, which was 

 tlien known to be a constituent of Turkey red, the mad- 

 der dyestufT, was a derivative of anthracene and antlira- 

 cene was found in coal-tar. In the same year Graebe and 

 Tiiebormann succeeded in makin<^' artificial alizarine from 

 anthracene, which was identical with Turkey red. The 

 invention was (juickl}' taken nj) by manufacturers and ar- 

 tificial alizarine superseded Turkey red, thus makiiii^ 

 unprofitable the cultivation of the madder ])lant. In 

 1875 I had the privilege of meeting Liebennann and also 

 Hofmann on the occasion of the seventv-fifth anniversarv 

 of Woehler's birth. On that occasion Prof. Liebermann 

 related to us how thev had worked on the svnthesis of 

 alizarine. When success was assured they repeated the 

 entire process in a single ni,i::ht, to make sure of results 

 before publication. At that time there was no ])atent 

 law in the North German Federation, and patents had to 

 be secured in three dozen ])rinci])alities. Tliis made 

 them of little value, and the inventors gave their work 

 to the ]mblic, securing for themselves only the immor- 

 tality of their names. 



The process of making artificial indigo is largely cred- 

 ited to Adolph V. Bayer, who recognized its constitution. 

 But many years of tedious work were required before 

 the Biidische Aniline & Soda Fabrik succeeded in ])re- 

 paring artificial indigo at a ])rice caj)able of competing 

 with the natural article. Since 1897, however, artificial 

 indigo has been sold and soon afterwards a process was 

 worked out which made use of na])hthalene as a raw 

 material. Xa])lithalene was always available in great 

 quantities and at a low ])rice, and the na]>hthalene pro- 

 cess made it ])ossible to drive natural indigo out of the 

 market. An interesting story is connected with the inven- 

 tion of the nai)hthalene process, the first step of which 

 was to transform naphthalene into ])htliali(' acid. For- 

 merly })htliali(' acid was pre])ared by oxidation of Naph- 

 thalene with nitric acid or chromic acid at great cost. The 



