350 
Proceedings of the Royal Society 
Extreme length between the alveolar margin of the intermaxil- 
lary suture and middle of lamhdoidal crest, measured in a straight 
line, was in the adult male gorilla 10’7 inches ; in the adult female, 
8’9 inches; in the young female, 7'5 inches. The length, measured 
in a straight line, between the interorbital ridge and the middle of 
the lamhdoidal crest, was in the adult male gorilla 6-9 inches; in 
the adult female, 6 inches ; in the young female, 5T inches. 
2. Notice of a Eemarkable Piece of Fossil Amber. By Sir 
David Brewster, K.H., F.E.S. 
The piece of amber, now on the table, was found in the kingdom 
of Ava, and sent to me from India by the late Mr Gleorge Swinton, 
to whom the Society was indebted for many interesting objects of 
natural history from that country. It weighs 2|- lbs., and in its 
general aspect seems to differ considerably from the ordinary speci- 
mens of amber. The remarkable fact, however, which distinguishes 
it from all the specimens of amber I have seen or read of, is, that 
it is intersected in various directions by thin veins of a crystallised 
mineral substance. These veins are in some parts of it as thin as 
a sheet of paper, and in other parts about the twentieth of an 
inch thick. In order to determine the nature of the mineral I 
extracted a portion of the thickest vein, and having obtained, by 
cleavage, a small rhomb, I succeeded in measuring the inclination 
of its planes, and found it to he carbonate of lime. 
Pieces of amber of 2 or 3 lbs. weight are very rare. A specimen 
weighing 1 lb. is valued in Prussia at 50 dollars. The largest piece 
yet found is in the Koyal Museum at Berlin ; it weighs 18 lbs., 
and is said to be worth upwards of 7000 dollars. 
3. On the Cause and Cure of Cataract. By Sir David 
Brewster, K.H., F.E.S. Lond. and Edin. 
The author’s attention was called to this subject in consequen( 4 e 
of having had an attack of incipient cataract forty years ago. The 
laminge of the lens had separated so much as to exhibit rays of 
light, and the prismatic colours, round every source of light. At the 
end of eight months the larainge came into optical contact, the rays 
