Page:Popular Science Monthly Volume 12.djvu/115

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To the Editor of the Popular Science Monthly.

IR: Returning a day or two ago to Columbus at the end of our vacation, I last night took up the September number of Therein is a letter from Evanston, Illinois, in which some of Prof. Schneider's mistakes, in his article on "The Tides," are pointed out. Two or three years ago Mr. Schneider caused his explanation of the tides to be printed in a little periodical used extensively by Ohio teachers—I refer to Notes and Queries, Salem, Ohio. The errors of fact and philosophy were then pointed out in that journal. And, inasmuch as Prof. Carhart has abundantly exposed Mr. Schneider's mistakes, I content myself with showing a single point. The whole article on "The tides" is a bundle of absurdities, mistakes of fact and philosophy, and errors of figures in regard to quantity. Mr. Schneider, knowing absolutely nothing of the theory of the tides, as understood and explained for the last two hundred years, has concocted a mass of nonsense which is set out as the only rational theory. I incline to the opinion that the New York gentleman who advised you to print the article was playing a practical joke on Mr. Schneider, or else he belongs to that order of city mathematicians who recommended Benson's "Geometry," a work in which there is proof(?) that an inscribed polygon of twelve sides is exactly equal to the circle which contains the polygon—i. e., circumscribes the polygon. Had this new philosophy been put forth in the ordinary newspapers of the day, no notice would have been taken of it. On page 276, July number of we find the following: "The earth will then feel a centrifugal force on her side farthest from the moon, and equal to the centripetal force felt on her side facing the moon. These two equal forces, acting in opposite directions," etc. On page 279: "This



force [centrifugal] acts in a line tangent to the earth's orbit." Then the centripetal force must also act parallel to the "tangent to the earth's orbit;" and so, whether you are a mathematician or not, you can easily see that things are going on at loose ends, if they act in this way. (See Fig. 1.) Did you ever elsewhere see, or hear either, of such a centripetal or such a centrifugal force?



Again, on page 276: "This large amount of centrifugal force is produced by axial rotation, by revolution round the sun, and by revolution round the centre of gravity [between the earth and the moon] already named."

Let us see: the centrifugal force, in connection with the revolution of the earth on its axis, is uniform all around the equator