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Show iVMsce-IIany The Great Mystery of the Tides, j Ey G-ARETT P. SERVISS. j We may liken the ocean to a. respiring giant thai st retches Ids vast length arounr all our coasts, whose breath is the flood of wnterw, now poured impetuously impetu-ously Into eveiy bay nnd inlet as the monster mon-ster exhales. ;ind now swiftly drawn out again with his next Inhalation, while, co-incidentally, co-incidentally, his broad breiiHt heaves nml falls rhythmically, I Ik- nn vies rise n iul pink, feeling the resistless power of tlin llff! that shirnhors u inlcrnca th their keels. Rut il is a forrrri breathing, this of great Neptune, ;i ntl bo would lie ni ill n s death but for two life-snvera in the sky whnii strive without ''eii.siiiE to save hint from suffocation through the atacrnatlnn of Ills own waters. The Humanum are the moon and the sun, aw every school dill I is taught without with-out understanding, .1 u x l as m us. I of t.i s know that a pu I motor m:i y bring a rirow nerl man tn 1 i t o a ga 1 n wl thout com -prflieurling exaclly how. This is the mys'e"y of Hie tirlep. and a mystery it remains, in part, although mankind has wondered about it and st 11 riled it from time I m memorial. Although Al-though it liail been noticed long before New ion was born I )i; t I hero was a syn -chronlsm between the motion of the moon a no the l id 05, yet was not until he had developed his theory of gravitation gravita-tion that t bp mannrr of the moon's action ac-tion in producing tides became plain. The moon is the principal agent, more than t wlee as effort I e as the sun. and since they both work in the same way, il is nn necessary to in t rod uco more t bun ohm rase of them in n simple ex pla n;i -t ion. Tha t ey pla nn t Ion depends upon I h ree proved fncts first, tint the attraction of irravitation Increases n force with the decrease of distance; second, that the solid etirth vtoMs as a wholo, united Kviy to tiie gravitational pull :f the rimon, and. t hf rd, t hat the ocea n, be ng com pnsM of watery pari idey free io move among one, a not I ),.-. doeM not yield to the lunai ' tug as a whole united body, hut its waters wa-ters flow over tiie earth's crust toward 1 the place, where the resultant of t he forces acting upon them Is grealrnt. The consequence- if that thov are. in a '-n.-:e. heaped or swelled up In a (trial wnve, rmd tb rot nt Inn of the f;irth on Its axis carries this wave westward, or in a direction contrary to that of the ro-1 ro-1 ration. So, if -von envelop a school ; globe in a sheet of gauze and hold the pause so thai il cannot, turn with the globe when Die latter is rotated. tiie gauze will move over its ho r fa re in an I opposl te di reet ion. Your hand, ga ther-! ther-! lug up and holding the gauze, on one side, may represent the attraction of tiie 1 moon upon the oceanic waters. I The water is he.upc-d up by the moon's ; I attraction in accordance with the first ij of the three, fun lament al facts mpn-j mpn-j tioni'd above; namely, that the attrac-1 attrac-1 tion Increases wit li decrease of disiaive. In truth, it Increases inversely as the squa re of the dis'a nco, wlhi'ii a ui -nen - s the effect. Tiie side of the earth that is at any time toward the moon is about 4a00 miles nearer the moon than the center of the earth. Hut, according to our second, fundamental funda-mental fact, the earth yields as a single solid body, to whivh we may now add that the effect of the pull is the same as if the entire substance of the earth were concentrated at iis center. It follows fol-lows that the waters of the ocean, being free to move over their solid bed, and experiencing an attraction greater than t hat felt at the earth's center, tend to flow toward the place where the moon's attraction Is greatest. Now conies the point usually found most difficult to understand. There is a tide on the aide of t lie earth turned from the moon as well as on the side turned toward it. This Is a result of the same fundamental facts. The water on the side opposite to the moon is 4000 miles farther from the moon than the center of tho earth, and is, consequently, proportionately less attracted. Thus the earth, as a whole, tends to be drawn, away from the water on that side, just as on the other side the water tends to be drawn away from the earth-This earth-This is in substance, the theory of the tides, and no doubt it is true explanation of their fundamental cause. Hut great difficulties arise when the theory is applied ap-plied to the actual tides that flow around the coasts of the continents. If Hie earth were a smooth sphere, covered everywhere every-where with an ocean of unvarying depth, there would be no difficulties of t lie kind. kHiit then we should either not exist at all or else we should be fish, or whales or sharks, and in that vase, instead of astronomers, physicists, and mathematicians mathema-ticians we should probably produce only big eaters. Taking the situation as it Is we find that the tides play the deuce with the theory. They do not disprove it, but they show that it is altogether insufficient insuffi-cient to cover the facts. The sources of tiie trouble are the varying depths 'of the water and the subdivision of the ocean into many different seas, more or less completely separated by huge, oddly-shaped oddly-shaped continents. Because the human mind loves simplicity, sim-plicity, which is easy to understand, and shrinks from complications, persistent at- : tempts have heen made to force the tides into compliance with a uniform theory, but they refuse. Thus it has long- been ttaught, in the text books, that the tides are all associated associ-ated pails of one universal "world phenomenon." phe-nomenon." We have been told of "a parent wave," starting- in the broad deep waters of the southern Pacific, and gradually grad-ually spreading round tho globe, combining com-bining in its course with minor tides started in smaller oceans. This parent tide has even been imaginatively, im-aginatively, but with authoritative assertion, asser-tion, traced around distant capes, through straits and across the length and breadth of many seas. One text book writer has averred that this tide is "fortv hours old" when it reaches Florida from the Pacific, and nearly "sixty hours old" when it begins to wash upon the shores of the North sea. Now, all this must be abandoned as pure speculation, according to the investigations inves-tigations of our coast and geodetic survey. sur-vey. Although, as Dr. Charles Lane Poor says, "the theory that the tides are a world phenomen lias the support of the world's greatest mathematicians and all the prestige their names can lend," the investigations referred to seem to prove that the tides "are strictly local in character and in being, and that the tides of the Atlantic ocean are due to the oscillations oscil-lations in the waters of the Atlantic, independent in-dependent of what has happened, or may happen, in the waters of the Pacific." Still nobody doubts that the sun and the moon are the causers of the tides, but Neptune, instead of being a single, appears as a multiple, giant who breatht'U with many watery lungs. |