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XLVII. Proceedings of Learned Societies. 
ROYAL SOCIETY. 
April6.— A PAPER was read On observations made with 
an invariable pendulum at Greenwich, and at 
Port Bowen; by Lieut H. Forster, R.N., F.R.S. 
April 13.—The following papers were read: On the diurnal 
variation of the needle at Port Bowen; by Capt. W. E. Parry, 
R.N., F.R.S., and Lieut. H. Forster, R.N., F.R.S. 
On the dip of the needle at different latitudes between 
Woolwich and Port Bowen; by Lieut. Forster. 
On the magnetism imparted to iron by rotation; by the 
same: with remarks by S. H. Christie, Esq. M.A., F.R.S. 
April 20.—A paper was read On a formula expressing the 
decrement of human life ; by Thomas Young, M.D. For. Sec. 
LINNZAN SOCIETY. 
April 4.—The following papers were read :—On dichoto- 
mous and quinary arrangements in Natural History ; by Hen. 
Thos. Colebrooke, Esq. F.R.S. F.L.S. &c. 
The learned author states that what has been called the 
dichotomous arrangement of nature can only be represented 
on a superficies: whereas the affinities of natural objects ramify 
in every direction, and cannot therefore be correctly repre- 
sented on a plane surface. He then shows that that distribu- 
tion which, taking one central or interior group, makes only 
a few equidistant exterior ones, is necessarily quinary. The 
centres of the exterior groups will represent the solid angles 
of a tetrahedron within a sphere of which the centre is the 
middle point in the interior group.-—He finally observes, that 
although the tendency to a quinary arrangement in natural 
history has hitherto been chiefly developed in zoology, yet the 
same principle may be recognised in botany. 
Also a communication, by the same author, On Boswellia, 
and certain Indian Terebinthacee. Mr. Colebrooke is of opi- 
nion that the three genera Amyris, Icica, and Bursera require 
to be thrown together and recast: the whole group com- 
prising nearly. 40 species, several of which are unpublished. 
Among those described are Boswellia serrata, Bursera serrata, 
Chalcas nitida, Amyris heptaphylla, A. punctata, Bergera in- 
tegerrima, and B. Kenigiz. 
April 18.—A large collection of the plants of Nepal was 
presented from the East India Company. The papers read 
were a continuation of Mr.Colebrooke’s on Boswellia, and cer- 
tain Indian Terebinthacee ;—and observations on a species of 
Simia 
