oe Ss 
State of the Physical Sciences. 299 
cP 
ence during ten or a hundred vibrations, before it is withdrawn 
by the motion of translation. his theoretical exposition of the 
subject should be generally adopted by mathematicians, the spec- 
troscopic observations on the supposed motion of th must 
direct vision spectroscope, the two edges of the sun’s equator, one 
ich was rotating toward him and the other from him, and 
Vogel has repeated 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. 
hen Voltaire visited England in 1727 he saw at the univer- 
Sities 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 
in philosophy as in other things: he left the world full, he finds 
t empty.” The e comparison might be made now, not so 
much between nationalities as between successive stages of scien- 
be 
was as empty as an exhausted receiver: now it has fi up again. 
rrence of a vacuum has been resuscitated, though 
for other reasons than these which satisfied the Aristotelians. It 
discussing the relative merits of the plenum and the vacuum. 
Newton, A his third letter to Bentley, wrote in this wise: “ That 
gravity should be innate, inherent and essential to matter, so that 
ne body may act upon another at a distance, through a anaes 
me so great an absurdity, that I believe no man, who has in philo- 
Sophical matters a competent faculty of thinking, can ever fall 
