FROM TORRES STRAIT TO HONG-KONG. 
116 
We left the island about noon on the 17th, and steaming through the channel 
between Hieri and Halmaheira, we proceeded to cross the Molucca Passage in a north¬ 
westerly direction towards the Strait of Banka. On the 18th we passed between the islands 
of Tifore and Mayo, two hilly, tree-covered tracts, situated in the centre of the Passage. In 
the afternoon of this 
day we witnessed the 
formation of a water¬ 
spout under precisely 
the same conditions as 
on a former occasion 
in the Sea of Banda, 
namely, a fine day with 
passing showers, little 
or no wind, and a large 
J o 
isolated cumulus cloud, 
the horizontal base of 
The mass of falling- 
which may have been about 1000 feet above the surface of the sea. 
rain below the cloud was seen to divide itself into separate columns, which soon afterwards 
assumed the cylindrical and undulating shape of a waterspout. The impression produced 
at the time was that the sudden cooling and condensation of the column of air beneath 
the cloud, while surrounded by an atmosphere of a very high temperature, may have some 
connection with the production of this remarkable phenomenon. The gradual formation 
and dissolution of the waterspout could be distinctly observed. The evening closed in with 
heavy rain showers. 
At daybreak on the 19th, the northern end of Celebes, with the lofty cone of Mount 
Klobat (6700 feet), the islands of Banka, Bejaren, Roang, and Tagulanda, were in sight. 
Later in the day we obtained a good view of the active volcano of Roang. Its reddish 
slopes, shaded towards the base with patches of dark green, were surmounted by a column 
of smoke. Most of the islands amongst which we had been lately navigating rise abruptly 
from the sea, and suggest the idea that they are the remains of a former continent now 
submerged. This observation may be extended to the whole Indian Archipelago, the gradual 
sinking of which was perhaps simultaneous with and compensated by the elevation of the 
neighbouring continent of Australia. 
The Challenger was now entering the Sea of Celebes, and the rays of a tropical 
sunset lighted up the whole range of islands from Siao in the north-east to Tana Manado 
in the south-west. October 20th was spent in trawling near Siao Island, the western end of 
which is occupied by an active volcano of considerable height ; and at daylight on the 21st 
the island of Sanguir was visible to the eastward. This proved one of the hottest days of 
our cruise, and the thermometer when lowered into the sea registered the unusually high 
temperature of 88° F., or 31 0 C, 
