The commencement of the effect, and the period of its general intensity, or strength, are to be inferred from the situation of the place of the eclipse with respect to the angles. For, if the ecliptical place be near the eastern horizon, the effect will begin to be manifested in the course of the first four months after the date of the eclipse; and its general height, or intensity, will take place in, or about, the first third part of the whole extent of its duration. If the ecliptical place happen to be in or near the mid-heaven, the effect will begin to appear in the second four months, and its general intensity will occur about the second third part; and, if the place should fall near the western horizon, the effect will begin in the third four months, and take its general intensity in the last third part of its whole duration.[87] [85] Temporal or solar hours are duodecimal parts of the Sun’s diurnal or nocturnal arc, and are numbered by day from sunrise to sunset; by night, from sunset to sunrise. [86] Equatorial hours are the twenty-four hours of the earth’s revolution on its axis. Each of them is equal in duration to the passage of 15 degrees of the Equator; and they are numbered from noon to noon. A particular explanation of the astronomical use, both of temporal and equatorial hours, is to be found in the 9th Chapter of the second Book of the Almagest; an extract from which is given in the Appendix. [87] The three periods of four months each, stated in this paragraph, are applicable to solar eclipses only; for lunar eclipses, these periods may be reckoned at ten days each; that number of days bearing the same proportion to a month, as four months to a year. On this point, Whalley, with his usual inaccuracy, has asserted, that “in eclipses of the Moon, two days, or thereabouts, are equal to the four months” here reckoned in eclipses of the Sun. He adds, however, what perhaps may be true, that “lunar eclipses are by no means so powerful as those of the Sun, although more so than any other lunation.” Partial intensities, or relaxations of the effect, are, however, to be inferred from any combinations which may happen during the intermediate period,[88] either in the actual places where the primary cause was presented, or in other places configurated therewith. They are also to be conjectured by the various courses, or transits, of such planets as co-operate in producing the effect, by being configurated with the sign in which the primary cause was situated; and, with this view, the matutine, vespertine, or stationary position, or midnight culmination of those planets must be observed; for the effect will be strengthened and augmented by their matutine or stationary position; but weakened and diminished by their being vespertine, or situated under the sunbeams, or by their midnight culmination.