'to it, it is enabled to fecure its young much more effectually c ^jAFfrom
deftruition, than the other fpecies, which are very *— i
prolific.
Mr. Gillibert acquainted me that a great quantity of yellow
amber is frequently dug up in the Lithuanian forefts,
fometimes in pieces as large as one’s fift, and that it is probably
the production of a fmall refinous pine % He informed
me that the duchy abounds in iron ochre, called by
Linnaeus Tophus humofo ocbreaceus, and defcribed by Walle-
rius + under the article o f Ferrutn limofum, which produces
forty pounds of metal in an hundred weighty that it yields
alfo feveral fpecies of copper and iron pyrites ; black agate,
which always bears a refemblance to the roots of pines
detached maffes of red and grey granite; pudding ftones,
containing chryftals of white quartz-; the echinus agatized ;■
* Naturalifts haVe long'differed concerning
t-he origin o f amber. Some maintain it .
to be an animal fubftance ;• others clafs it
among the minerals; fome aiTert, that it is
'a vegetable oil united with a mineral acid ;
but the moil: common opinion feems to be
that it is a foffil bitumen. A few, with
Mr. Gillibert, hold it bo be the refinous
juice of a pine hardened by a g e : this latter
opinion was alfo maintained by the antient
Romans. Amber -is moftufually found upon
the fea-eoaft, and though frequently difco-
vered feveral feet beneath the fur face o f the
ground, yet has been ftippofed to have
never been dug up at any •eonfiderable
diitance from-the fea ; a circumltance which
has led feveral naturalifts to conjecture,
that it owes, in a great meafure, its pro- •
du&ion to thefea. But this hypothefis is confuted
by the difcovery o f thefe large pieces
■of amber in the heart o f the Lithuanian fo- ■
refts far from any fea. See Plin. Hift. Nat.
37. Sec. X L Tacitus, -de Mor. Germ.
Macquaire’s Chymiftry, v. II. p. 206. Bifhop
of Landaff’a (Dr. Watfon) Eflays onChym.
v. III. p. 12, and particularly Wallerius
F f
Syft. Min. v. I I . p . 115— 117. where the
reader will find a lift: o f the principal naturalifts,
who have written upon Amber,
f Wallerius, Syf. Min. v . I I . p. 255. . „
J Mr. Gillibert thus defcribes thele
agates in the a£ts o f the Imperial Academy
o f Sciences. “ Mr. Gillebert dans une let-*
“ tre à Mr. le Profièfleur Pallas, parle
“ d’ une petrification très remarquable,
“ commune dans ce pays [Lithuania], la-
“ quelle eft agathe par fa nature, mais re-
“ lem'ble -parfarte ment par fa. forme, à des
“ racines de lapins .pétrifiées’. Les racines
“ agatifées lon’t bàndéesdê noir autour de leur
“ axe, et incruftées d’une écorfè grife ou
“ blanchâtre. On en trouve à demi petri-
£« fiées.;’ et toutes donnent' une odeur era-
“ pyreumatique au feu, qui provient d’un
“ relie de principe bitumeneux. D ’Ailleurs
“ toutes les pétrifie a tions d ’origine- marine
“ fe trouvent agatiféçs dans ce pays couvert
“ d’un fable fin, dont les eaux peuvent ex»
“ traire dn principe pétrifiant de cette na-
“ ture.’* Nov. A â . Acad. Pet. for 177-7,
p. 4S*
à