28 . 



§ 5. The r('lali("»n (4) also lollovvs IVoin 0(|ii;ili()ii (lOrO of' llx' 



l);i[)i'r hy Süminikkfki.i» (p. 184), (|ii()(c'(l in nolo 2 p. 2 1 . if <Mtcciin'iiig 



10 

 llicre is put ecpial to — , as luis been snp[)Osc(l in (lie rchilions (8) 



and (4) ^iven above, and if in SoMMKHi'Kr.D's expi'ession //, is i-c[)lai'e(l 

 by h h '). The latler elian^i>e is conneeted vvilli ilie farl, tluvl in 

 derivinu;' the expressions given here the snpi)osition was made that 

 in considering Ihe nioleenlar translalory motion in an ideal monalomie 

 o-as we have to deal with eneruy elements ot a magnitude .' Itv, as 

 we tried to make probable in Suppl. N", 80rt § 2. 



The fact that in § 4 a satisfactory agreement with experimental 

 data was obtained, ma}-, if' the validitj- of the other h^ipotheses is 

 admitted as sufficiently approximate, be regarded as a confirmation 

 of the above supposition concerning the magnitude of the energy 

 elements. 



Astronomy. — "'On Seeliger'.v hypothesis about the anomalies in 

 the motion of the inner planets.'" By J. Woltjer Jr. (('Om- 

 municated by Prof. W. de Sitter). 



(Communicated in the meeting of April 24, 1914). 



To explain the differences between observation and calculation in 

 the secular jjerturbations of the elements of the four inner planets, 

 Seeliger ^) worked out the hypothesis that these are caused by masses 

 of matter, which by reflection of sunlight offer the aspect of the 

 zodiacal light. He imagines these masses to have the form of a flat 

 disc surrounding the sun and e.\ tending nearly in the direction of 

 the orbital planes of the planets and reaching outside the orbit of 

 the earth; the density of the matter within the disc has its greatest 

 value in the proximity of the sun, though it is very small even there. 

 For the calculation of the attraction of the mass of uuitter sjjecial 

 hy[)Otheses on its constitution are introduced; we imagine a number 

 of very flattened ellipsoids of revolution with the sun at the centre, 

 the inclinations of the equatorial planes to the orbital planes of the 

 planets being small. It is evident thar by the superposition of a number 

 of such ellipsoids we get a flat disc within which the deusity varies 



1) This confirms at the same lime liie fact, that the introduction of the zero 

 point energy does not produce a change in the value of the entropy constant. 



2) Das Zodiakallicht und die enipirischen Glicder in der Bevvegung der innern 

 Planeten. Silzungsberichte der Bayerischen Akademie, XXXVi 1906. 



