| XXX | (472) | XXX |
472
A S T R O N O M Y. in which the Harveft-moons are leaft beneficial. L S 1756 1757 1758 *759 1753 1773 175? 1772 1754 1777 1776 1778 1775 1774 1 1790 1791 1792 1796
- 795 1815
793 1813 1794 1814 1809 18x0 l8l £ 1812 1828 1829 1830 1831 1832 1833 1834 1846 1847 1849 1850 1851 1852 Tears in which they are mojl beneficial. M S N 1760 1761 1762 1763 1764 1765 1766 1767 1768 1769 1779 1780 1781 1782 1783 1784 1785 1786 1787 1798 1799 1800 1801 1802 1803 1804 1805 1806 1816 1817 1818 1819 1820 1821 1822 1823 1824 182 j 1835 1836 1837' 1838 1839 1840 1841 1842 1843 1853 1834 1855 1856 i8j7 1858 1859 i860 1861 At the polar circles, when the fpn touches the fummer be below the horizon during that half of the year. But tropic, he continues 24 hours above the horizon, and 24 when the fun is in the fouthern half of the ecliptic, he hours below it when he touches the winter tropic. For never rifes to the north pole, during which half of the the fame reafon, the full moon neither rifes in fummer, year, every full moon happens in fome part of the northnor fets in winter, confidering her as moving in the ec- ern half of the ecliptic, which never fets. Confequentliptic. For the winter full moon being as high in the ly, as the polar inhabitants never fee the full moon in ecliptic as the fummer fun, muft therefore continue as fummer, they have her always in the winter, before, at, long above the horizon; and the fummer full moon being and after the full, Ihining for 14 of our days and nights. as low in the ecliptic as the winter fun, can no more rife And when the fun is at his greateft depreflion below the than he does. But thefe are only the two full moons horizon, being then in Capricorn, the moon is at her which happen about the tropics, for all the others rife and firft quarter in Aries,- full in Cancer, and at her third fet. In fummer, the full moons are low, and their ftay quarter in Libra. And as the beginning of Aries is the is Ihort above the horizon, when the nights are ftiort, rifing point of the ecliptic, Cancer the higheft, and Liand we have leaft occafion. for moon-light: In.winter, bra the fetting point, the moon rifes at her firft quarter they go high, and ftay long above the horizon, when the in Aries, is moft elevated above the hqrizon, and full in nights are long, and we want the greateft quantity of Cancer, and fets at the beginning of Libra in her third quarter, having continued vifible for 14 diurnal rotations moon-light. At the poles, one half of the ecliptic never fets, and of the earth. Thus the poles are fupplied one half of the other half* never rifes; and therefore, as the fun is the winter time with conftant moon-light in the fun’s always half a year in deferibing one half of the ecliptic, abfence; and only lofe fight of the moon from her third and as long in going through the other half, it is natural to her firft quarter, while fixe gives but very little light, to imagine that the fun continues half a year together a- and could be but of little, and fometimes of no fervice bove the horizon of each pole in its turn, and as long to them. A bare view of the figure (Plate XLIV. fig. below it, rifing to one pole when he fets to the other. 3.) u'ill make this plain; in which let S be the fun, e This would be exaftly the cafe if there were no refrac- the earth in fummer when its north pole n inclines'totion ; but by the atmofphere’s refrading the fun’s rays, ward the fun, and E the earth in winter, when its north he becomes vifible fome days fooner, and continues fome north pole declines from him. i’FAfand NIVS is the days longer in fight than he would otherwife do: fo that horizon of the north pole, which is coincident with the he appears above the horizon of either pole before he equator; and, in both thefe pofitions of the earth, is the moon’s orbit, in whieh fixe goes round has got below the horizon of the other. And as he never goes more than' 234 degrees below the horizon of the earth according to the order of the letters abed, the poles, they have very little dark night; it being twi- ABCD. When the moon is at a, (he is in her third light there as well as at all other places till the fun be quarter to the earth at <?, and juft rifing to the north pole 18 degrees below the horizon. The full moon being al- n; at 3 fhe changes, and is at the greateft height above ways oppofite to the fun, can never be feen while the fun the horizon, as the fun likewife is ; at r Ihe is in her firft is above the horizon, except when the moon falls in the quarter, fetting below the horizon ; and is loweft of all northern half of her orbit; for whenever any point of under it at d, when oppofite to the fufl, and her enlightthe ecliptic rifes, the oppofite point fets. Therefore, as ened fide toward the earth. But then Ihe is full in view the fun is above the horizon of the north pole from the to the fouth pole p, which is as much turned from the 20th of March till the 23d of September, it is plain, fun as the north pole inclines towards him. Thus, in that the moon, when full, being oppofite to the fun, muft our fummer, the moon is above the horizon of the north pole Tears N 1751 1752 1770 1771 1788 • 17S9 1807 1808 1826 1827 i 844 1845
