2 4 o SCIENCE PROGRESS 



where he could work during the evenings and vacations when 

 the College was closed. 



Whilst still researching, under Hofmann, Perkin was struck 

 with the idea of attempting to synthesise quinine from allyl- 

 toluidine by oxidation, since, with the vague views on organic 

 chemistry held in those days, the reaction expressed thus : 



2 (C 10 H 13 N) + 30= C 20 H 24 N 2 O 2 + H 2 



seemed perfectly feasible. 



On attempting the oxidation, however, by means of potas- 

 sium bichromate a dark-coloured precipitate was produced, 

 and in order to examine the reaction under simpler conditions 

 Perkin tried the oxidation of aniline itself with the same oxi- 

 dising agent and again obtained a dark precipitate insoluble 

 in water, but which dissolved in alcohol to a violet solution 

 which dyed silk a magnificent purple colour. He was at once 

 struck with the vast possibilities opened up by the discovery 

 should the use of the dye prove successful on a technical scale, 

 and sent specimens of the new colouring matter, which he 

 named " aniline purple," to Messrs. Pullars of Perth, and on 

 June 12, 1856, he received a reply: " If your discovery does 

 not make the goods too expensive it is decidedly the most 

 valuable that has come out for a long time. This colour is 

 one which has been very much wanted in all classes of goods, 

 and could not be obtained fast on silks, and only at very great 

 expense on cotton yarns ... on silk the colour has always 

 been fugitive : it is done with cudbear or archil and then 

 blued to shade." 



Perkin finally decided to patent it, and on August 26, 1856, 

 Patent No. 1,984 was issued to him. 



Although at this time only eighteen years old, Perkin made 

 up his mind to leave Hofmann and the Royal College of 

 Chemistry, in order to undertake the manufacture of the new 

 dye on a large scale, in spite of Hofmann 's endeavours to 

 dissuade him. With the assistance and co-operation of his 

 father and brother, a small factory was started at Greenford 

 Green near Harrow. 



It must be remembered that in those days aniline was a 

 fairly new substance, rarely seen outside of one or two research 

 laboratories, and Perkin 's first task was to find out the right 

 conditions for obtaining it from benzene. 



