_ Astronomical and Nautical Collections. 309 
northwards ; and then, turning still more to the right, the line seems 
to become N.W. and §.E. till at last the tide runs almost due east, 
_up the British Channel, [while another part of it passes] round the 
north of Scotland into the Northern Ocean, sending off a branch 
down the North Sea to meet the succeeding tide at the mouth of 
the Thames. 
“ Fourthly, towards Cape Horn again there is a good deal of 
irregularity; the hour-lines are much compressed between South 
Georgia and Terra del Fuego, perhaps on account of the shallower 
water about the Falkland Islands and South Shetland. 
Tn the fifth place, at the entrance of the Pacific Ocean, the 
tides seem to advance very rapidly to New Zealand and Easter 
Island; but here it appears to be uncertain whether the line of 
contemporary tides should be drawn nearly north and south 
from the Gallapagos to Terra del Fuego, or N.E. and S.W. from 
Easter Island to New Zealand; or whether both these partial di- 
rections are correct: but on each side of this line there are great 
irregularities, and many more observations are wanting before the 
progress of the tide can be traced, with any tolerable accuracy, 
among the multitudinous islands of the Pacific Ocean, where it 
might have been hoped that the phenomena would haye been 
observed in their greatest simplicity, and in their most genuine form. 
'“ Lastly, of the Indian Ocean the northern parts exhibit great 
irregularities, and among the rest they afford the singular pheno- 
menon observed by Halley in the port of Tonkin, and explained by 
Newton in the Principia: the southern parts are only remarkable 
for having the hour lines of contemporary tides considerably 
crowded between New Holland and the Cape of Good Hope, as if 
the seas of those parts were shallower than elsewhere.” 
The second section relates to the “ disturbing forces that occa- 
sion the tides,” and presents nothing that is not readily demon- 
strable, and indeed universally admitted, except, perhaps, the 
magnitude of the primitive elevation, produced by the lunar and 
solar forces, which is made two feet and ten inches respectively, or 
at the very utmost 2} feet and eleven inches, for the actual density 
of the earth and sea, instead of the much greater height commonly 
