CORRESP ONDENCE. 



105 



CORRESPONDENCE. 



"THE TIDES." 



To the Ed~.or of the Popular Science Monthly. 



SIR : Returning a day or two ago to Co- 

 lumbus at the end of our vacation, I 

 last night took up the September number of 

 The Popular Science Monthly. 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, Sa- 

 lem, Ohio. The errors of fact and philoso- 



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 2*76, July 

 number of The Popular Science Monthly, 

 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 2*79: "This 



Fig. 1. 



phy were then pointed out in that journal. 

 And, inasmuch as Prof. Carhart has abun- 

 dantly 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 philos- 

 ophy, and errors of figures in regard to 

 quantity. Mr. Schneider, knowing abso- 

 lutely nothing of the theory of the tides, as 



o- 



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 ? 



Fig. 2. 



understood and explained for the last two 

 hundred years, has concocted a mass of 

 nonsense which is set out as the only ra- 

 tional 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 rec- 

 ommended Benson's " Geometry," a work 



Again, on pa<re 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 contrifugal force, in con- 

 nection with the revolution of the earth on 

 its axis, is uniform all around the equator 



