150 THE MICHIGAN ACADEMY OF SCIENCE. 



''He then proceeds to discuss solar and lunar tides in the atmosphere 

 and the water of the earth 'Thus the lunar attraction pro- 

 duces as it were the action of a friction brake resisting the earth's rota- 

 tion. The same is no doubt also the case in respect to the sun and the 

 water of the ocean.' 



"The last paragraph begins^'Thus with the approximate results of 

 observation used above in respect of the earth's atmosphere and the as- 

 sumption we have now made regarding the lunar tides we have a state 

 of things' (paraphrasing his statement) by which a spot on the surface 

 of the earth would be advanced in rotation 2. .5 seconds in the course of 

 one hundred years through the thermodynamic acceleration and put 

 back 2.5 seconds through the tidal retardation — retardation by tidal fric- 

 tion — that is, it loses in all 22.5 seconds, or say 22 seconds, which is 

 Adams' result. The earth turns more slowly by tAventy-two seconds each 

 century, owing to tidal friction." 



Sir James A. Eussell adds : "He' finds that the attraction of the sun 

 and moon producing tides in the atmosphere have little sensible effect 

 upon the barometer." From that statement and from the title of the 

 paper, — "On the Thermodynamic Acceleration of the Earth's Rotation" 

 I infer that Sir William Thomson at that time found the effects of the 

 radiant energy from the sun not sufficient to maintain the earth's rota- 

 tion against the resistance of the solar and lunar attraction. Whether 

 or not he took into consideration the influence of the wind, I do not 

 know; I infer that he did not. I do not feel sure that at that time he 

 had before him so much evidence as now seems apparent for estimating 

 the amount of energy in the pressure of the atmosphere on that part of 

 the earth where it is most available for rotational effect. Therefore 

 the evidence in this paper is respectfully offered in the hope that the 

 subject may be again taken up and considered by Sir William Thomson, 

 now Lord Kelvin, or by some other person more competent than the 

 author of this paper to mathematically weigh the facts. If, as I believe, 

 the retardation due to solar and lunar attraction does not actually oc- 

 cur, there must be some equal and constant accelerating cause. Until 

 it is disproved, I shall consider that it is probably the wind and the 

 atmospheric pressure. 

 Henry B. Baker^, Lansing, Michigan, March, 1904. 



