380 
The mean errors have been taken from Nrwcomes. For the moon 
we have '): 
Observed Theory Difference 
_ \Brown, Cowen, -+14643536"42") a ay je 3 
ae Newcoms, DE Vos 14643530 +2 yg peas So 
dst Newcoms, Brown — 6967944 +2 — 6967939 +2 —5 +3 
With respect to the perihelion of Mercury we may remark that 
the residual, which without the new term, resulting from EiNsTEIN’s 
theory (but with the improved constant of precession) would be 
+ 8".24, has now become negative. The matter within the orbit of 
Mercury, by the attraction of which Srrricer explained the anomalous 
motion of the perihelion, must thus have an exceedingly small 
density, certainly less than say ‘/,,,%% of the value adopted by 
SEELIGER. | 
The residuals now show no preference for either the positive or 
the negative sign; there is thus no reason to suppose a rotation of 
the empirical system of coordinates with respect to the inertial system, 
as was done by ANpiNG and Seeiierer. In other words the precessional 
constant as found from motions within the solar system is the same 
as that determined from the fixed stars. 
The residual of the node of Venus remains large. We might per- 
haps still be inclined to ascribe this deviation to the attraction of 
the masses reflecting the zodiacal light (Srerricer’s second ellipsoid). 
Since the rotation cannot help us, the density of this ellipsoid would 
then have to be 3 or 4 times the value assumed by SEELIGER. From 
the computations by Mr. Worrser *) it has appeared that this 
density can certainly not exceed SrELIGER’s value, because a larger 
density would give values for the secular variation of the inclination 
of the ecliptic and for the planetary precession, which are absolutely 
contradictory to the results of observations. SPELIGER’s second ellip- 
soid can thus not explain the observed discrepancies *). Corrections 
1) The motion of the lunar perigee and node, these Proceedings XVII 
(April 1915) page 1309. 
2) J. WoLtsER. On SEELIGER’s hypothesis, these Proceedings XVII (April 1914) 
page 23; W. pe Sitter, Remarks on Mr. WoutJeR’s paper, ibid. page 33. 
5) If Seenicer’s second ellipsoid is adopted with the density ascribed to it by 
SEELIGER, We would find the following residuals, 
edw sin id % di 
Mercury — 0.”47 + 0.43 + 0.49 + 0.48 + 0.44 + 0.”80 
Venus — 0.10 + £.25 = 0.395. 17 + 037+ 33 
Earth + 0.05 + .13 + 023-4 21 
Mars + 046+ 35 — 004+ .22 -- 0,01 + .20 
The value of di for the earth is the secular variation of the inclination of the 
