Tidal range Tidal range Tidal range is the height difference between high tide and low tide. Tides are the rise and fall of sea levels caused by gravitational forces exerted by the Moon and Sun and the rotation of Earth. Tidal range is not constant but changes depending on the locations of the Moon and Sun. The most extreme tidal range occurs during spring tides, when the gravitational forces of both the Moon and Sun are aligned (syzygy), reinforcing each other in the same direction (new moon) or in opposite directions (full moon). During neap tides, when the Moon and Sun's gravitational
Disquisitions relating to Matter and Spirit Disquisitions relating to Matter and Spirit Disquisitions relating to Matter and Spirit (1777) is a major work of metaphysics written by eighteenth-century British polymath Joseph Priestley and published by Joseph Johnson. Between 1774 and 1778, while he was serving as an assistant to Lord Shelburne, Priestley wrote five major metaphysical works, in which he outlined his materialist philosophy, even though such a position "entailed denial of free will and the soul." In the first of these works, "The Examination of Dr. Reid's Inquiry. . . Dr. Beattie's Essay. . . and Dr. Oswald's Appeal" (1774), Priestley had strongly suggested that