ohtaified in the distillation of Wood, 'zffc, 27 



discovery would form a material addition to those useful ones for 

 which the arts have been indebted to chemistry. 



As nothing tends more to confusion of ideas than confusion of 

 terms, I may be excused for proposing a name to the pitch of dis- 

 tilled wood, a name in familiar use, though hitherto unappropriated 

 by chemists. It is in fact that which is well known to painters by 

 the name of Bistre, although the nature of bistre has I believe never 

 yet been examined ; and the importance of it to the arts of design 

 induces me to extend this article for a few lines. According to Dr. 

 Lewis, bistre is produced from the soot of all wood, other receipt 

 books give us the same account, but limit the sort of wood to 

 beech without seeming aware of its real nature j but the colourmen 

 use the soot of all wood indiscriminately. 



Those artists who have made the tour of the highlands of Scot- 

 land, are well acquainted with that variety of it which varnishes 

 the interior of a highland cottage. 



In all these cases it is a very variable article, and the colour-maker 

 being unacquainted with its real nature, is unable to rectify its faults, 

 in consequence of which it is often unfit for use, notwithstanding 

 the various operose and mysterious purifications it undergoes in his 

 workshop. The causes of these varieties will be very evident to 

 those who have read the foregoing experiments. An imperfect 

 separation of essential oil and a consequent tenacity arising from its 

 too near alliance to the tar, will appear to be its most common vice, 

 and it is this which gives it that disagreeable gumminess and dis- 

 position to return to the pencil which is destructive of its best 

 qualities. At times also from the same causes it is offensively yellow. 

 So valuable is a brown colour that will work freely and with 

 transparency, that the artists will be much obliged to him who shall 

 render bistre equal in freedom and force to seppia. By distilling 



D 2 



