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PROFESSOR EDWARD HULL, LL.D., F.R.S., OX 



be in a fluid or viscous condition, is in continuous contact, there 

 is no other way in which the displaced lateral matter can 

 remain in a state of equilibrium. "Where water occupies the 

 surface, the effect is to produce, on both sides, a wave following 

 the course of the moon, owing to the rotation of the earth once 

 every 24 hours, which has its fullest development when the great 

 Pacific is the scene of operations. But the bulging due to 

 compression also necessarily adds to the magnitude of the tidal 

 wave directly opposite the moon. These conditions may be 

 illustrated by the annexed figure. (See diagram.) 



E 1 













J 



E 



Let M be the centre of the Moon and C- the centre of the 

 Earth. By joining these the line MC 2 traverses the surface of 

 the Earth at C 1 , and. it prolonged, the antipodal surface at C 3 . 

 The attraction of the Moon is greatest along this line, and least 

 at E and E 1 , where the tangents to the Earth's surface from M 

 meet it. The triangle MEE 1 , which represents the forces of 

 attraction to the Moon's centre, mav be resolved into two 

 triangles MC 2 E and MC-E 1 . In MC-E the line EC 2 represents 

 the component of the Moon's attraction that acts towards the 

 centre of the Earth : and similarly WC 2 in the triangle MC-E 1 . 

 The action of the Moon's attraction at E and E 1 has in part, 

 therefore, a compressing effect upon the surface of the Earth, 

 producing bulging at (J 1 and C 3 , as already explained. These 

 bulgings produce on oceanic waters a tidal wave at C 3 and 

 augment the direct tidal wave at C 1 . 



Xow, I wish to protest most sincerely that 1 have no intention 

 of contesting the theories of professed astronomers, who may 

 naturally hesitate to accept my views. On the contrary. I hold 

 that this problem of the antitidal wave may not be inconsistent 

 with theirs. You will observe that my own branch of science, 

 Geology, is here specially called into service, and I venture to 

 call this paper " A Geological Theory of the Tidal Wave on the 

 Off Side of the Moon," and I may add that outside the 

 " astronomic group " of scientists I have found supporters for 

 my views. 



