January 30, 1920] 



SCIENCE 



105 



though the change may prove aperiodic, and 

 a lesser one of about 70 years. Professor 

 IN'ewcomb says :' 



Taken in connection with the recent exliaustive 

 researches of Brown, which seem to be complete in 

 determining with precision the action of every 

 known mass of matter upon the moon, the present 

 study seems to prove beyond serious doubt the 

 actuality of the large unexplained fluctuations in 

 the moon's mean motion to which I have called at- 

 tention at various times during the past forty 

 years. 



And he concludes, after examining every 

 known cause of motion, that " if we pass to 

 unknown causes and inquire what is the 

 simplest sort of action that would explain all 

 the phenomena, the answer would be — a fluc- 

 tuation in the attraction between the earth 

 and the moon."^ This is in line with my 

 present suggestion, but as yet we have no 

 certain knowledge whether there is corre- 

 spondence between the supposed attractive 

 change and the solar emission of electrons. 

 However, the comparison which Professor E. 

 W. Brown has made between the variation of 

 the moon's mean motion in longitude and the 

 fluctuation in height of the maxima of the 

 sun-spot curve'' lend considerable confirma- 

 tion to the view that the 70-year period in 

 the moon's motion is in fact due to a varying 

 electric repulsion between the moon and the 

 earth owing to the larger reception, by both 

 bodies, of negative electrons when sun-spot 

 maxima are highest and when, presimiably, 

 solar electronic emission is exceptionally 

 great, with consequent slight reduction of 

 gravitational control and loss of motion owing 

 to electronic repulsion. We might suppose 

 that the electrons thus received by our earth 

 from the sun, form a fluctuating electronic 

 " atmosphere," outside of the denser air, but 

 attached to the planet. ISTipher's experiment, 

 however, favors the supposition that there is 

 actual electronic penetration into the solid 

 substance of the outer layers of the earth. 



6 Op. cit., p. 164. 



6 Op. cit., p. 169. 



7 See Report of the Australian meeting of the 

 British Association for the Advancement of Sci- 

 ence, Transactions Sect. A, pages 311 to 321. 



Professor Brown says :^ " With some change 

 of phase the periods of high and low maxima 

 correspond nearly with the fluctuations above," 

 referring to his curve of the variations of the 

 moon's motion in longitude, where negative 

 values of the moon's motion-variation from 

 the mean follow close after the high sun-spot 

 maxima of 1780 and 1850, while positive lunar 

 values (that is, increased speed from greater 

 total attraction) are equally associated with 

 the low solar maxima of the epochs near 1S15 

 and 1885, or half way between the epochs of 

 high sun-spot maxima. Nevertheless, as the 

 electric hypothesis was then imbroached. 

 Brown considered the connection open to 

 doubt because, as he says, " it is difficult to 

 understand how, under the electron theory of 

 magnetic storms, the motions of moon and 

 planets can be sensibly afEected." But this 

 difficulty which was felt when the only hy- 

 pothesis in sight was that of some sort of 

 magnetic effect, disappears in the light of 

 the now known efficacy of electronic penetra- 

 tion. Similar, though much smaller varia- 

 tions, with apparently identical period, are 

 foimd in the motions of Mercury and the 

 Earth in respect to the sun, but in these there 

 are some discrepancies, and until these are 

 cleared up, the proposed explanation, though 

 plausible and perhaps even probable, can not 

 be considered as certainly established. 



F. W. Very 



WeSTWOOD AsTROPHTSICAla OBSERVATORY, 



Westwood, Mass. 



FRANK PERKINS WHITMANi 



Professor Whitman was of New England 

 stock. The Whitman (originally Wightman) 

 family came to Massachusetts in 1632. The 

 line of Whitmans has included three clergy- 

 men. The father of Frank was William 

 Warren, early in life a lawyer, but later en- 

 gaged in business, who died in 1902, at the 

 age of eighty-two. Caroline Keith Perkins, 

 the mother of Frank, died at the age of forty- 

 one. She and the mother of President Taylor, 



8 Op. cit., p. 321. 



1 Minute adopted by the Undergraduate Colleges 

 of Western Keserve University. 



