of Tanning a?id Dyeing. 149 



Dr. Bancroft was perhaps the first who noticed the oxygenize- 

 ment of barks. He attributes the dark-brown colour of the epi- 

 dermis of fits quercitron to this cause ; and as a confirmation of 

 the idea, 1 have observed that ink made of the epidermis of an- 

 other kind of bark, though at first not to be distinguished by the 

 colour from that made of the cellular and cortical parts, is in- 

 comparably less permanent. 



As a material for making ink, the wood of the chesnut is pro- 

 bably unrivalled. Combined with iron in anv proportion, it gives, 

 as it is dilute or concentrated, a pure blue or blue- black ; while 

 galls, sumach, &c. &:c. unless combined with a greater propor- 

 tion than is consistent with the highest degree of permanency, 

 afford a black more or less inclining to a reddish brown. The 

 lake of the chesnut is indeed a blue, and not to be distinguished 

 by the eye from indigo ; but when diffused on paper, this same 

 substance becomes an intense shining black. In dyeing, little 

 difference is observable between the chesnut and galls, and su- 

 mach, except that the former has a rather greater affinityfor wool. 

 See. than the latter, arid of course requires less boiling. Its perma- 

 nency has been completely tested by long exposure to the sun and 

 the weather ; but no doubt can exist on this head, if the posi- 

 tion of Rerthoilet be true, that permanent blacks are formed only 

 by the combination of iron and tannin. 



To prepare the chesnut wood for the purposes of tanning, a 

 mode has been devised for reducing it to a suitable degree of fine- 

 ness. This method consists in the application of knives, either 

 in the direction of, or transversely to, the grain, by a rotatory 

 motion. This mode obviously involves the greatest possible oeco- 

 nomy of moving power. Messrs B. and M. Stebbins, of West- 

 Springfield, who are making arrangements for going largely into 

 the exportation of the article, have in construction a machine 

 upon this plan. 



As might be expected, the inspissated aqueous extract of the 

 chesnut bears a near resemblance in many particulars to cate- 

 chu. Professor Dewey, of William's College, whr at my request 

 has gone through an extensive and elaborate course of experi- 

 ments, informed me that he obtained a quarter more of the ge- 

 latinous precipitate from the former than from the latter. By 

 the taste, the two substances are not to be distinguished, except 

 that the former is more pungent. It leaves upon the tongue 

 the same permanent and refreshing sweetness for which the 

 other is so much prized in the East ; where it is used as an article 

 of luxury, with betel nut. Might not the extract be advantage- 

 ously substituted for catechu, in the celel)ratc(l life-preserving 

 composition of Dr. Pearson ; the object being to concentrate the 



K3 greatest 



