dented on its margin. Mr. Darwin
measured one which was nearly eight feet in diameter, and therefore no
less than twenty-four in circumference. The stalk is rather more than
a yard high, and each plant sends out four or five of these enormous
leaves, presenting together a very noble appearance.

The barks replete with the tanning principle should be stripped with
hatchets and bills from the trunk and branches of trees in spring,
when their sap flows most freely. The average quantity of oak bark
obtained from our forests is estimated at 150,000 tons annually, of
which Ireland and Scotland furnish but a very small quantity.

The following table, given by Dr. Ure, shows the quantity of
extractive matter and tannin yielded by different substances:--

In 480 parts In 100 parts
by Davy. by Cadet.
Sicilian sumach 78 --
Malaga ditto 79 --
Souchong tea 48 --
Green tea 41 --
Bombay catechu 261 --
Bengal ditto 231 --
Nutgalls 127 46
Bark of pomegranate -- 32
" Virginian sumach -- 10
" Carolina ditto -- 5

Catechu and Gambier are very valuable for tanning, and are alluded to
under the heads GAMBIER and ARECA PALM.

CATECHU is obtained from the _Acacia Catechu_, an arboreous tree
growing from fifteen to twenty feet high, with a brown and scabrous
bark. The interior wood is brown, dark red or blackish, and the
exterior white, one or two inches thick. It inhabits various parts of
the East Indies, of which it is a native, and is also now common in
Jamaica. It bears whitish or pale yellow flowers.

The catechu obtained from this tree in Pegu, is celebrated throughout
India, and fetches L4 to L5 more per ton than gambier and other
astringent extracts. When of good quality, catechu is more powerful as
an astringent than kino. Of all the astringent substances we know,
catechu appears to contain the largest proportion of tannin, and Mr.
Purkis found that one pound was equivalent to seven or eight of oak
bark for tanning leather.

The term catechu, observes Dr. Pereira, is applied to various
astringent extracts imported from India and the neighbouring
countries. A few years ago t