JOURNAL AND PROCEEDINGS. 3F 
moorings because “‘xostris id erat incogniaum”—his legionaries. 
being accustomed to the navigation of the Mediterranean where 
the tides are hardly uoticable. While Pliny says, “‘verum causa in 
sole lunaque”’—Seleucus, the Babylonian living near the Red Sea, 
noticed that when the Moon was in the equinoctial the tides followed 
each other regularly, but when she is not there, but in the solstices,,. 
thr height and succession of the tides were irregular, and that this. 
irregularity depended upon her distance from the equator. Modern. 
astronomers would express that by stating that the diurnal inequality 
vanishes when the Moon is on the equator, and is at its maximum 
when the declination is greatest. Seleucus must have watched the 
Atlantic tides where this diurnal inequality is almost evanescent, and 
he must have observed the tides of the Indian Ocean, especially 
about Aden, where the diurnal inequality is very great. Kepler in- 
dicated that the Sun and Moon moved the water, but his suggestion 
of gravitation was the merest surmise, and Galileo criticised Kepler 
in not exhibiting his usual acuteness while he referred the phenom- 
ena to the rotation of the Earth. 
The true theory of tide generating force was not expounded until: 
Newton, in his Principia in 1687, by his genius established the 
foundation on which the whole philosophy of tides rests. If I may 
be permitted to rest and turn aside from the path of serious and. 
honest inquiry, and to drift into Mohammedan romance, I may 
quote from the prophet “‘ on whom be the blessings of God and His. 
peace,” when he says, ‘‘ Verily the angel who is set over the seas 
places his foot in the sea and thence comes the flow, then he raises. 
it and thence comes the ebb.” 
We are all more or less familiar with the ordinary theory of the 
tides. 
