serve as a Substitute for Oak Bark . 43.1'. 
red, and sometimes blue or black* The cause of this 
phenomenon is known to chemists, who know also how 
to make these decoctions or infusions transparent, and to 
make the colours disappear, by pouring into them, drop 
by drop, a sufficient quantity of oil of vitriol. 
The properties of these plants being thus sufficiently 
ascertained, and there being the greatest plenty of them 
in the country, it remains now for the connoisseurs to ex- 
tend the use of them, and to apply them further to the 
advantage of our national manufactures. 
A List of the Plants that have been used in the ^Experi- 
ments on Tanning * 
The number of plants fit for tanning is much greater 
than that of those in the following list; and it has been 
observed that, if they be gathered at proper seasons, they 
can be used for the preparing of all sorts of skins, both 
coarse and fine. The best of them are such as have the 
greatest quantity of a coarse, astringent, and acid sub- 
stance. They are also the fitter for penetrating the skins, 
in proportion as they contain a greater portion of aroma- 
tic and spirituous parts, and are possessed of an essential 
ethereous oil. On the contrary, the inferior species of 
them are those whose substance is principally composed 
of fat or mucilaginous parts, which do not make so strong 
an impression on the skins, and can scarce serve for tan- 
ning the most tender ones. 
Salicaria vulgaris purpurea , foliis oblongis . Tourm 
Instit. 253. Lysimachia spicata purpurea, forte Plinio* 
Co B. pin. 346. Purple-flowered loosestrife. 
Ulniaria; Clus. Hist. 198. 1. B. hi. 488. Regina prativ 
Bodon. Pernpt. 5'7. Queen of the meadows. 
Comarum; Linn. Hen. pi. ed. 5. 563. Quinquefo- 
1mm palustre rubrum . C. B. pin, 336, Red marsh 
cinquefoiL 
