of Edinburgh, Session 1875-76. 
113 
4. Note on the Volcanoes of the Hawaiian Islands. By J. W. 
Nichol, F.RA.S. Communicated by Professor Tait. 
The late Transit of Venus Expedition gave the writer some 
opportunities of visiting several islands of the Hawaiian Archi- 
pelago, some details of which may prove interesting. 
They form a group of islands about 10J hours west longitude 
from Greenwich, and about 20° to 22° north of the equator, and 
differ in size from 10 miles long by 6 or 7 broad, to 90 miles by GO, 
which are about the dimensions of the most easterly and largest, 
viz., Hawaii (the Owyhee of Cook). The general lie of the islands 
is from north-west to south-east, those in the east displaying the 
most recent traces of volcanic activity. In the older or western 
portion the main mountain ranges run in the same direction as the 
islands, rising in many places to a height of 3000 to 4000 feet, and 
having lateral ridges branching off at right angles, with an occa- 
sional crater of oval shape thrown up at a distance from them, and 
evidently of more recent origin. 
The putting up of a meridian mark on one of these ridges in 
the island of Oahu was attended with some difficulty, the narrow 
space along which one had to ride, sometimes not more than a yard 
or two wide, with precipitous descents of 500 to 1000 feet on 
either side, not rendering it comfortable to any one with weak 
nerves. 
The two most easterly islands, viz., Maui and Hawaii, although 
having their greatest length in the north-east and south-west 
directions, are composed only of mountains standing singly, and 
present no appearance of ranges. Maui, indeed, is nothing more 
than a couple of mountains joined by a very low neck of land, on 
the top of the eastermost of which (Mount Haleakala), at a height 
of 11,000 feet, is found one of the largest and most perfect extinct 
craters in the world, being some 10 miles in diameter, which unfor- 
tunately time would not admit of our visiting. The sides of 
Haleakala are not precipitous, and the general view from the sea is 
that of a huge hog-backed mountain. Traces of flows of lava so 
recent as to be quite black, and not covered with vegetation, are 
also seen coming down from what had been openings in its sides a 
short distance above the sea-level. 
VOL. IX. 
Q 
