ADDRESS OF PROFESSOR LOVERING. 647° 
displacements when he examined, with a direct vision spectro- 
scope, the two edges of the sun’s equator, one of which was 
rotating towards him and the other from him, and Vogel has re- 
peated the observation with a reversion-spectroscope. This would 
have the force of a crucial experiment were it not that an equal 
displacement was seen on other parallels of latitude, and that the 
bright bands of the chromosphere were moved but not the dark 
lines of the solar atmosphere. 
When Voltaire visited England in.1727 he saw at the universi- 
ties the effect of Newton’s revolutionary ideas in astronomy. 
The mechanism of gravitation had exiled the fanciful vortices of 
Descartes, which were still circulating on the continent. So he 
Wrote : ‘‘A Frenchman who comes to London finds many changes 
n philosophy as in other things: he left the world full, he finds it 
empty.” The same comparison might be made now, not so much 
between nationalities as between successive stages of scientific 
development. At the beginning of this century the universe was 
as empty as an exhausted receiver: now it has filled up again. 
Nature’s abhorrence of a vacuum has been resuscitated, though 
for other reasons than those which satisfied the Aristotelians. It 
ls the mathematicians and not the metaphysicians who are now 
discussing the relative merits of the plenum and the vacuum. 
Newton in his third letter to Bentley wrote in this wise :—“ That 
sravity should be innate, inherent and essential to matter, so that 
oe body may act upon another at a distance, through a vacuum, 
without the mediation of anything else, by and through which 
their action and force may be conveyed from one to another, is to 
me so great an absurdity, that I believe no man, who has in philo- 
“ophical matters a competent faculty of thinking, can ever fall 
nto it.” Roger Cotes, who was Newton’s successor in the chair 
of mathematics and natural philosophy at Cambridge, was only 
years old when the first edition of the Principia was issued, 
d Newton outlived him by ten years. The venerable teacher 
Pronounced upon the young mathematician, his pupil, these few 
> Comprehensive words of eulogy: “If Cotes had lived, we 
ve known something.” The view taken of gravitation 
by Cotes was not the same as that held by his master. He adyo- 
meet the proposition that action at a distance must be accepted 
Prete of the primary qualities of matter, admitting of no farther 
malysis, It was objected by Hobbes and other metaphysicians, 
