Elements of astronomy ..with explanatory notes, and questions for examination . them, explaining the meaning of high tide and low tide 1 TIDES. 275 begins to swell in the same manner as before, and thusfrom year to year, and from century to century, the ebb andflow of the ocean follow each other at regular intervalsof time. 678. From the above explanation it will be seen thatthere are daily two high tides and two low tides. The in-terval of time between two successive high or low tides,is about 12h. 25m. Accordingly when there is a hightide at any place, as New York, for instance, th
Elements of astronomy ..with explanatory notes, and questions for examination . them, explaining the meaning of high tide and low tide 1 TIDES. 275 begins to swell in the same manner as before, and thusfrom year to year, and from century to century, the ebb andflow of the ocean follow each other at regular intervalsof time. 678. From the above explanation it will be seen thatthere are daily two high tides and two low tides. The in-terval of time between two successive high or low tides,is about 12h. 25m. Accordingly when there is a hightide at any place, as New York, for instance, there mustalso be a high tide on the opposite side of the globe, andthe same is true in respect to a low tide. These pointsare illustrated in Fig. 79, where O and O1 representthe places where the high tides, and B and C, those wherethe low tides simultaneously occur on the HIGH AND LOW TIDES 679. A marked correspondence exists between themotion of the tides and the motion of the moon. If to-dayat 10 A. M., it is high tide in a certain harbor, it will behigh tide to morrow in the same harbor at lOh. A. M. The interval therefore that elapses be-tween any high tide and the next but one after it, is 28sec. Now this is the exact amount of time thatintervenes between two successive passages of the moonover the meridian of any place. In fact as the earth re-volves on her axis, the tide wave tends to keep under themoon, and thus sweeps around the globe from any portto the same port again, in the precise period of time that How many high tides and low tides occur daily ? Whnt is the interval of lime betweentwo successive high or low tides? When a high tide for instance occurs at any portwhere is there then also another high tide 1 Explain the Figure. What marked eorres--pondence is here alluded to 1 Describe it particularly 1 276 SOLAK SYSTEM
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Keywords: ., bookcentury1800, bookdecade1850, bookidelem, booksubjectastronomy
