Capt. J. Rodgers on Tides at Tahiti. 151 
Art. XVII.— Observations of Tides at Tuhiti, made for the U. & 
Coast Survey, under the direction of Captain JoHN RopcErs, 
-S..N. Communicated by Prof. A. D. Bacuz, Supt. 
U.S. Coast Survey. 
THE tides at Tahiti have long been known to exhibit the pe- 
culiarity of occurring nearly at the same hour of every day, 
indicating an almost total elimination of the lunar tide. 
As far as we know, the tides of no other part of the globe 
present this extraordinary feature. No explanation fully satis- 
factory has yet been proposed for this phenomenon. 
From their bearing on the laws regulating the tides on the 
North American coast of the Pacific Ocean, accurate tidal obser- 
vations in central parts of that ocean are a great desideratum, 
and advantage was thérefore taken by the Superintendent of the 
t Survey, of the surveying expedition under the command 
of Captain John Rodgers, U.S. N., by furnishing him with one 
of Saxton’s self-registering tide-gauges, with the request to set it 
up at some suitable point. 
The town of Papeete, on the island of Tahiti, was selected by 
Captain Rodgers, and the tide-gauge left there under the charge 
of an intelligent French soldier. The observations began on the 
27th of April, 1858, but up to June 2d were so frequently inter- 
Tupted as to be of little use. After that date, they are nearly 
complete to October 12th, subsequent to which time no observa- 
tions have been received. 
ag 
of - month of June the tide appears to have followed the gen- 
igh-waters occurred 
ata later hour on successive days, but only until they had 
Teached three or four hours, and, in one case oh oe of 
October 12th, when the observations ceased, only the range and 
the abruptness of the return to an earlier hour becoming les- 
Sened, a 
It will also be remarked that the midnight tides diverge less 
from that hour than the midday tides from noon. ihe times o 
‘OW-water have, as may be expected, similar relations to 6 A. M. 
and 6 p. M. a 
eae 
