190 VEGETABLE SUBSTANCES. 



more reasonable rate, should not speedily lead to 

 the universal practice of transporting it in a con- 

 centrated form. But a prejudice exists which 

 hitherto has prevented its general introduction, and 

 this can be only gradually overcome. 



The quality of leather is estimated in the trade 

 partly by its colour ; the paler it is the higher value 

 it obtains, for experience has shown that bark 

 having been injured by fermentation produces a 

 brown leather, which is brittle and of a bad quality ; 

 and since this hue has formerly been justly associated 

 with inferiority, it still continues to be considered one 

 of the criteria by which the quality of leather is to 

 be judged. Both alder and larch bark make excel- 

 lent leather, but being of a reddish brown colour it 

 is very difficult of sale. The extracts of the barks 

 give more colour to the leather than the unprepared 

 oak bark, and although this darker tint does not appear 

 to be attended with any kind of inferiority, it is from 

 this circumstance alone considered of a lower quality. 



When the results of scientific research are a little 

 better known to practical men, the dislike of inno- 

 vation will, no doubt, be removed. In the mean time 

 constant discoveries and improvements are being made 

 in this, as in every other branch of domestic industry, 

 and the mode of preparation is, in consequence, 

 much superior to that practised a few years back. 



A tanner of Bern Castel, on the Moselle, has 

 recently discovered that the vaccinium myrtillus, or 

 whortle berry, is admirably adapted for the prepara- 

 tion of leather. It is cut down in the spring, and 

 when dry reduced to powder. Three pounds and a 

 half of this tan are said to be equivalent to six of oak 

 bark, while at the same time the process of tanning 

 is very much accelerated by its use. 



A commission was appointed at Treves for exam- 

 ining the leather so tanned, and the report speaks 



