W. Harkness—The Solar Parallax. 3 375 
Art. LI.— On the Relative Accuracy of a ete cre of 
Determining the Sotar Parallax; by WM 
{The substance of this paper was read before the American Association for the 
Advancement of Science, at Cincinnati, August, 1881.] 
THE object of this , paper is to compare the various methods 
of determining the solar parallax, and to show that the photo- 
The following notation will be employed in algebraic formule : 
a@ =mean distance of the earth from the su 
a,=that distance between the earth and iis sun which would 
satisfy Kepler’s third law 
=mean distance of the cath from the moon. 
=a constant such beet 
=the mass of the rth 
€ =eccentricity of eh? moon’s orbit. 
é, =eccentr icity of the earth’s orbit. 
. G =observed force of gravity at a point upon the surface of the 
kh 
oe 
ick 
=Gauss’s constant for the solar system. 
L =constant of the earth’s lunar inequality. 
=length of simple peu 
M =the mass of the m 
m =ratio of the mean akin of the sun and moon 007480133. 
P =the constant of lunar parallax =3422"°7. 
P,=that value of the constant of lunar parallax which would sat- 
isfy Kepler’s third law. 
=the constant of solar parallax 
=the amine in inequality of the moon. 
=the ma 
Sig larean latitude of the m 
=length of the sidereal year, acu! in seconds of mean time » 
=31,558 
=length of the sdereal month, expressed in seconds of mean 
Monee, = 2,360,5915 
5 be 
a, <5 
V =the “yakaity of light. 
a@ =the constant of aberration. 
y =Delaunay’s constant, which is approximately sin 4 aera ce 
of lunar orbit to plane of ecliptique), and the t value 
of which is 0°04488663. See DTL., vol. i 
4 =the time taken by light to traverse the mean radius of the 
earth’s orbit 
f@ =motion of moon’s node, relatively to the line of equinoxes, in 
3654 days. 
v =the heliocentric longitude of the earth, 
