JOURNAL 



O F 



NATURAL PHILOSOPHY, CHEMISTRY, 



AND 



THE ARTS. 



FEBRUARY 1800. 



A R T I C L E I. 



Experiments on Indigo. — By a ComfpondenL* 



To. Mr. NICHOLSON. p 



Edinburgh, jfan. 4, 1 800. 

 SIR, 



I 



WISH, through the medium of your Journal, to make known to chemifts fome experi- 

 ments, which, I hope, will not only be reckoned curious in themfelves, (as they fcem to 

 throw a new light on a colouring matter procured from organic bodies) but of much mo- 

 ment, as they relate to a fubftance, of the utmoft value to our commerce and manu- 

 fadiures. 



The commodity I allude to is the dye indigo, in which I think I have detc£l:cd a new 

 principle, which has been overlooked by other chemifts; this principle is of fo volatile a 

 nature, that it could only be difcovered by the means I ufed, to which I was accidentally 

 led by my firft experiment, as you will obferve in the fequel ; and jnay mark the reafon 

 why the accurate Scheele, Bergman, and others, have taken no notice of it, as they inva- 

 riably calcined the carbonaceous refidue in the open air. 



• This communication was accompanied by a letter containing the name and addrefs of the author, and 

 ■aJfo of the friend to whom he makes his acknowledgment8.---N. 



VoL.IIL— February iSoo. 3 0^ If 



