Geology and Natural History. 405 
The result obtained was, that Huygens’ construction gives the 
true law of double refrac tion within the limits of errors of obser- 
e 
I intend to prese sent to the vis ted Society a detailed account 
of the observations; but in the mean time the publication of 
this preliminary notice of the pelt obtained may possibly 
be useful to those Noe, Ses in the theory of double refraction.— 
Phil. Mag., IV, xliv 
3. ok a new Galvanic Pile, of economic construction ; by 
M. Garrrr.—The high price of galvanic en and the difficulty 
of procuring them being often an obstacle to the applications 
which might be made of them, I essayed the ‘aoc of de- 
vising an apparatus that one could make anyw without the aid 
of the professional workman, with pis sen Alte of little value, 
widely spread in commerce, and possessing the essential quality of 
so roqpte im ae effects. 
é m, used som years since on tele graphic lines ; 
but its elements are different. It co sists = a aa into which 
dip two rods—one of lead, the other of zinc. The leaden “ne aod 
ape to the bottom ; the zinc is eotelk. shorter. The bot 
the vessel is coated with red oxide of lead (minium); hid 
te — liquid is water Te 10 per cent of hablorby arate 
amm 
& bun 
the cent ag of zine formed does not sensibly alter the con- 
ductivity of the exciting liquid; , ts constancy is reci finally 
expense is almost nothing when the circuit is open.— Com 
oe ae de _— d. des pene Je ne 15, 1872, p 120.— Phil. Mag., 
;x 
Il. Grotogy AND NatTuRAL History. 
1. Discovery Mf Fossil Quadrumana in the Eocene of Wyom- 
ing ; by O. C. Marsu.—An examination of more complete apo 
mens of some of the extinct Mammals already described by th 
Writer from the Eocene deposits of the Rocky Mountain region, 
clearly indicate that among them are several representatives of the 
yl er obs asdgarpens Although these remains differ widely from all 
forms of that group, their mite Big al tant iat 9 lard 
that the og should be placed with t $ coer 
» Thinolestes, anit Fidos olenn, en. ave the principal 
parte of the skeleton much as in some of t the cor. 
Tespondence in man the er bones being very close. The 
anterior part of the lore jaws is similar to that of the Marmosets, 
