552 
THE VOYAGE OF H.M.S CHALLENGER. 
August or middle of September, after which light variable winds are experienced, until 
the middle or end of November, when the northwest monsoon sets in. Although during 
the southeast monsoon rain squalls are frequent, the regular rainy season is the north- 
west monsoon ; the finest months are September and October. 
The tides in Dobbo Harbour are somewhat irregular ; during the stay, however, the 
diurnal inequality was very slight. It is high water at full and change at 2 hours 
30 minutes, and the tides rise 6 feet. The flood stream was of very little strength, but 
the ebb ran to the westward at the rate of from 1 to 1^ miles per hour at the anchorage. 
The coin in circulation at the village was the Dutch dollar, 4s. 2d., and rupee, 
Is. 8d., but the Chinamen were eager to obtain English gold. 
The Arrou Islands appear to be by no means visited so infrequently as one would 
suppose. The Malays stated that a Russian frigate had called there about two years 
previously, a small Italian vessel had been there not long before, and they also asserted 
that an English yawl had lately visited Dobbo, and the main islands of the group ; 
besides which a party of Americans, two years previously, stopped a considerable time in 
Kobroor, and one of them died and was buried there. 
The only supplies that could -be obtained were a few poor fowls at tw T o shillings each, 
and some eggs, twopence each ; occasionally a few fish were brought alongside. 
The Arrou Islands to the Ki Islands. 
Having procured astronomical and magnetic observations, the ship left Dobbo 
Harbour on the 23rd September for the Ki Islands. In going out of the harbour 
the water suddenly shoaled to 3i> fathoms, with the northwest point of Wamma Island 
S. 86° W., and Dobbo Spit S. 68° E. When Pulo Babi came open of Wamma Island, 
the water deepened to 16 and 20 fathoms, and shortly afterwards to 48 fathoms, with the 
extremity of Dobbo Spit S. 66° 40' E., the left extremity of Wassia Island N. 32° 4 0 r E., 
and the right extremity of Pulo Babi S. 17° E. At 10 a.m. a sounding, trawling, and 
temperatures were taken in 800 fathoms (Station 191), with Dobbo Spit S. 66° 40' E., the 
left extremity of Wassia Island N. 44° 20' E., and the right extremity of Pulo Babi 
S. 26° E., and at 6 p.m. sail was made for the north point of Great Ki Island (see Sheet 
32). Whilst trawling, the tide was setting northwest until 4 p.m. ; and as it was ebbing 
in Dobbo Harbour, it is probable that the ebb sets northwest, and the flood southeast. 
The Ki (Ke) Islands. 
On the 24th, at daylight, Great Ki Island was observed ahead. By observa- 
tions and bearings of the land, it was found that there had been a current of 20 miles 
to the westward since 6 p.m. of the previous day, at the rate of 1-| miles per hour. At 
6 a.m. a sounding and serial temperatures were taken in 580 fathoms, and then sail 
