serve as a Substitute for Oak Bark . 4$7 
pyreumatic oils, which it is rubbed with in the preparing 
of it. 
As to Cordovan and Morocco leather, they are made 
of goats’ skins, and prepared, the one with sumach, the 
other with galls. 
We have said enough concerning the general princi- 
ples of tanning, so as to throw a light upon what relates 
to the plants that can be made use of in it. 
There is abundance of these plants in our country, 
and eight new methods of preparing leather with them 
have been discovered. They have been treated of in a 
memoir that was repod before the academy on the 5 th of 
last December. The author of this memoir, and the ma- 
ker of these new sorts of leather, is M. Klein, a native 
of Nauen. He requested I should show him all the 
plants that I thought fit for tanning. I have mentioned 
the names of these plants to the academy, and specified 
their properties. They are all indigenous plants, very 
common and abundant, and which have been heretofore 
“ considered as noxious weeds, as the utility of them was 
not known ; and accordingly, their being used in tanning 
will not be in the least hurtful to private economy. M. 
Klein has collected a considerable quantity of these spe- 
cies of plants ; and among the eight sorts of leather that 
have been made with them there is very fine Cordovan 
prepared without sumach, and two sorts of calf-skin, 
tanned only with leaves of trees. 
These coriaceous plants grow in almost all deep 
places and marshy grounds; there are some of them 
found also in sandy soil, on hills, and in woods. The 
hay which they yield is the coarsest of all, and in very 
small quantity ; the cattle never touch it, except when 
they are starving with hunger. Such plants spoil 
good meadows. A great quantity of them is to be 
had, particularly near lakes and large ponds ; and it is 
