Persons who are unacquainted with the methods of calculating Eclipses and other astronomical phenomena, are prone to look upon the correctness of these calculations as powerful arguments in favour of the doctrine of the Earth’s rotundity and the Newtonian philosophy generally. But this is erroneous. Whatever theory is adopted, or if all theories are discarded, the same results may follow, because the necessary data may be tabulated and employed independently of all theory, or may be mixed up with any, even the most opposite doctrines, or kept distinct from every system, just as the operator may decide. The tables of the Moon’s relative positions for almost any second of time are purely practical, the result of long continued observation, and may or may not be mixed up with hypothesis. In Smith’s “Rise and progress of Astronomy,” speaking of Ptolemy, who lived in the 2nd century of the Christian Era, it is said, “The (considered) defects of his system did not prevent him from calculating all the Eclipses that were to happen for 600 years to come.” Professor Partington, at page 370 of his Lectures on Natural Philosophy, says, “The most ancient observations of which we are in possession, that are sufficiently accurate to be employed in astronomical calculations, are those made at Babylon about 719 before the Christian Era, of three Eclipses of the Moon. Ptolemy, who has transmitted them to us, employed them for determining the period of the Moon’s mean motion; and therefore had probably none more ancient on which he could depend. The Chaldeans, however, must have made a long series of observations before they could discover their “Saros” or lunar period of 6,585¹⁄₃ days, or about 18 years; at which time, as they had learnt, the place of the Moon, her _node_ and _apogee_ return nearly to the same situation with respect to the Earth and the Sun, and, of course, a series of nearly similar Eclipses occur.” Sir Richard Phillips, in his “Million of Facts,” at page 388, says:--“The precision of astronomy arises, not from theories, but from prolonged observations, and the regularity of the motions, or the ascertained uniformity of their irregularities. Ephemerides of the planets’ places, of Eclipses, &c., have been published for above 300 years, and were nearly as precise as at present.” “No particular theory is required to calculate Eclipses; and the calculations may be made with equal accuracy _independent of every theory_.”[20] [20] Somerville’s Physical Sciences, p. 46. SECTION 10. CAUSE OF TIDES.