Earth tide lunar and the solar tidal maxima and minima (bulges and depressions) add together for the greatest tidal range at particular latitudes. At first- and third-quarter phases of the moon, lunar and solar tides are perpendicular, and the tidal range is at a minimum. The semi-diurnal tides go through one full cycle (a high and low tide) about once every 12 hours and one full cycle of maximum height (a spring and neap tide) about once every 14 days. The development of a systematic theory of Earth tides was started by George H. Darwin in 1879, and was then furthered by
Full Moon Features product. Full Moon continued producing its releases throughout the early '90s (sometimes as many as twelve releases a year) and in 1993 founded two more labels: Torchlight Entertainment, specializing in softcore pornographic sci-fi comedies and Moonbeam Entertainment, specializing in family orientated sci-fi and fantasy films. Torchlight's first release was "Beach Babes From Beyond"; Moonbeam's was "Prehysteria!", which actually became a high seller for distributor Paramount and was one of the first Full Moon films to be sold as an inexpensive sell-through product (as most Full Moon features were sold on VHS as rental items with prices upwards of $100 for