Mr. T. Carrick on the Tides and the Earth's Rotation. 63 



covery of this metal, I may leave your readers to form their own 

 opinion as to the justice with which my right to that discovery 

 has been disputed, and as to the sufficiency of the argument that 

 I could not be aware of the metallic nature of thallium, because 

 I had not enough of it to melt into an ingot. 



But besides these points involving merely scientific credit, M. 

 Lamy and his friends have unmistakeably implied that I have 

 acted dishonourably in regard to him. I am accused of having 

 met him in company, of having gathered from him a knowledge 

 of the properties of thallium, and of having hastened to publish 

 that knowledge as the result of my own researches. 



It is chiefly on account of this insinuation that I have re- 

 quested you to allow me to make known a statement of the 

 whole facts of the case, and to show that the claim put forward 

 by M. Lamy rests on nothing but a partial statement of those 

 facts, and upon assumptions that have no real foundation. 

 I have the honour to be, Gentlemen, 



Your obedient Servant, 



20 Mornington Road, N.W. WlLLIAM CrOOKES. 



May 21st, 1863. 



VIII. Note on the Tides and the Earth's Rotation. 

 By Thomas Carrick, Esq. 



To the Editors of the Philosophical Magazine and Journal. 



Gentlemen, 



THE speculations of Dr. J. R. Mayer on the effect produced 

 by the tides on the earth's rotation, which appear in his 

 ' Essay on Celestial Dynamics/ reprinted in your Journal for 

 May 1863, are based upon the assumption that the tidal wave 

 always lies to the east of the moon's meridian, and has a slow 

 progressive motion from west to east, opposite in direction to 

 the rotation of the earth ; an assumption which cannot, I believe, 

 be justified consistently with the known facts of tidal motion in 

 any sense which warrants the conclusions sought to be indorsed 

 thereon. 



As Prof. Tyndall in his " Remarks on the Dynamical Theory 

 of Heat," published in the same Number of your Journal, has 

 indorsed Dr. Mayer's views, and as the subject appears likely 

 to undergo further discussion, it seems desirable to call atten- 

 tion to the untenable nature of the assumption. 



Our knowledge of the position and progress of tidal waves 

 is derived from observations of the time of high water on ocean 

 coasts, the direction in. which the hours increase along a given 

 coast being held to indicate the direction of the progressive 



