1901 - 2 .] Mr J. Fraser on Constitution of Matter and Ether. 45 
“ If attraction is the result of the impulsion of a fluid, its action, 
must employ a finite time in traversing the immense spaces which, 
separate the celestial bodies,” — I quote from Stallo’s Concepts of 
Modern Physics , and he (Stallo) goes on, — whereas there^is now 
no longer any reason to doubt that the action of gravity is instan- 
taneous. If it were otherwise — if gravity, like light or electricity, 
were propagated with a measurable velocity — there would necessarily 
be a composition of this velocity with the angular orbital velocities - 
of the planets, resulting in their acceleration ; the apparent line of 
attraction would be directed to a point in advance of the real 
place of the sun, just as the sun’s apparent position is displacedi 
in the direction of the earth’s orbital motion by the aberration of 
light.” Similarly, R. A. Proctor, in the Old and New Astronomy , 
p. 321: — “The direction in which the sun’s light seems to reach, 
the earth is not the true direction of a straight line joining the 
centres of the earth and sun, but is inclined to this direction so 
as to be directed from the earth to a point nearly 9200 miles from 
the sun’s centre. If gravity, acting outwards from the sun, tra- 
versed the interplanetary spaces with the same velocity as light, 
the pull of gravity would not be directed to the sun’s centre (which 
we have seen (Art. 465) is essential to the fulfilment of Kepler’s 
second law), but at an angle of about 20'445" to that direction. 
And precisely as the rays of light reach the earth with this slight 
slant directed towards her in her advance (as rain falling verti- 
cally seems to meet with a slight slant, directed towards him, a 
swiftly advancing traveller), so thq direction of the action of 
gravity on the earth would be inclined with a slant in the direction 
of the earth’s motion.” And then he goes on to show that this 
slight slant pull, if it existed, “ would communicate to the earth an 
increase of velocity in her orbit amounting to about half a millionth 
of a foot per second, and which would increase as the square of the 
time, and be very quickly rendered sensible.” 
The assumption underlying the above reasoning is that tho 
centre of the earth’s motion is situated on the line joining her own 
centre with that of the sun, and that the action of the sun on her 
is a pulling action. Kow, it is utterly inconceivable how one body 
could pull another without something of the nature of a cord, 
passing between the two, and which could be wound up as the 
