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CORRESPONDENCE. 411

demic. If through your published articles intelligent observation is directed toward the dangers inherent in our insect pests, and means are discovered to avert them, you will deserve the undying gratitude of suffering humanity.

Respectfully,A. G. Boardman.
Macon, Georgia, September 22, 1883.
 

 

TIDAL ANOMALIES.

Messrs. Editors:

Professor R. W. McFarland ("Popular Science Monthly," volume xii, page 106), after demonstrating, as a result of Professor Schneider's theory, a great inequality in the daily range of the tides, confidently asks, "Do your New York tides play such tricks?"

However it may be with the New York tides I will not undertake to say, but there are numerous localities upon the globe where the tides do play such or at least similar "tricks," seemingly at variance with established theories, and in some places these "tricks" appear to be contrary to all our preconceived notions of hydrodynamics. Thus, at the entrances of the various United States ports in the Gulf of Mexico, the tides either exhibit a great inequality in their daily range, or but one flood and ebb tide occurs in the course of the twenty-five hours usually occupied by the two tides. The one-tide phenomenon is again met with among the Philippine Islands; while tides exhibiting considerable daily inequality in their range are met with in numerous other places.

That part of the St. George's Channel called the Irish Sea included between the fifty-third and fifty-fifth parallel of latitude contains a body of water covering an area of about ten thousand square miles, inclosed on all sides, except at the two entrances, north and south of Ireland. Throughout this entire body of water the time of high water is nearly simultaneous, the difference nowhere exceeding an hour. Here the average mean range of the tides is not less, probably, than twenty feet. The water to supply and exhaust this broad area of unusually large range of tides has to pass in and out at the two entrances simultaneously with the rise and fall of the water in the Irish Sea.

Now, the puzzling thing about these tides is, owing to the time of high water at the two entrances being about five hours earlier than in the Irish Sea, at least two thirds of all this water passing in and out of the St. George's Channel has the appearance of running from a lower to a higher level. Here the tides exhibit another curious freak in the distribution of their range. On the east coast of Ireland, between Wexford and Wicklow Head, for some distance there are no rise and fall to the tides; while directly on the opposite side of the channel, on the coast of Wales, the mean range is not less than fifteen feet.

But this anomaly of the water apparently running up-hill, as exhibited by the tides, will be found more clearly marked at the Strait of Gibraltar, where the motion of the tidal wave is easterly, and the easterly tidal stream begins at high water, and the westerly tidal stream begins at low water. The same phenomenon is met with again at the Strait of San Bernardino, Philippine Islands, and also on our own coast, in Martha's Vineyard Sound, where the motion of the tidal wave is westerly, and the westerly tidal stream begins at high water. At Cook's Strait, New Zealand, the motion of the tidal wave is westerly, and the westerly stream begins at half flood.

These are only a few of the more clearly marked of the many anomalies that have come under my observation while endeavoring, as a navigator, to make myself acquainted with the concrete phenomena of the tides.

In the absence of a better explanation of these anomalies, I offer the following hypothesis: That the established theory of the tides is substantially correct; but, that the primary tidal wave is in the liquid portion of the earth beneath the solid (though to a greater or less extent flexible) crust; and that the tidal phenomenon as it reveals itself to us is a secondary tidal, undulatory motion, deriving its impulse from, and is complicated by, the variable flexibility of the solid crust between the two liquid portions of the earth.

George W. Grim (Bark Coryphene).
Yokohama, Japan.
 

 

ELEPHANTS' TRICKS.

Messrs. Editors:

The following extract from an old edition of the "Arabian Nights" (Edinburgh, 1772), may be of interest, showing as it does that at an early date elephants were trained to perform tricks which excite the curiosity if not the wonder of the spectators in the modern shows. It is from the story of "Prince Ahmed and the Fairy Pari-Banou ":

"But what the Prince Houssain most of all admired was the ingenious address and invention of some Indians, to make a large elephant stand with his four feet on a post which was fixed into the earth, and stood out of it above two feet, and beat time with his trunk to the music. Beside this there was another elephant as big as this and no less surprising; which being set upon a board which was laid across a strong rail about ten feet high, with a great weight at the other end which balanced him, kept time by the motions of his body and trunk as well as the other elephant, and both in the presence of the king and his whole court."

When this story was written I do not know, as this edition gives no notes as to the original sources of the stories.

Respectfully, Davis L. James.
Cincinnati, October 6, 1833.