289 
There is confessedly a need at present of a popular and 
accurate explanation of the theory and laws of The 8ame 
Gravitation, affected as we know it is by so 
many causes. Are we unfaithful to the law of 
gravitation, if we point people, in connection with this first 
principle, to a book like Mr. Proctor’s, The Sun Ruler of 
the Planetary System, for a statement of certain questions still 
awaiting solution ? Are we to upbraid men of science, if 
conclusions should be arrived at different from those to which 
they had accustomed us ? Above all, ought we to try to 
prejudice the expected conclusions by appeals to old astrono- 
mical bigotry ? Eather we should say, in proportion as we 
are sure of our principles, we hold ourselves free to meet all 
facts. 
Or, again ; Questions will soon be raised in connection with 
the ensuing pair of transits of Menus in 1874 and 1882. 
Eight years have elapsed since the astronomers assured the 
public not only, as we knew, that Encke's observations and 
calculations had been imperfect, but that science had been 
very materially in error, in consequence, as to the mean 
distance of the earth from our central luminary, the sun. An 
error amounting to about four millions of miles, as Mr. Hind 
pointed out, could not imply changes of slight importance. 
But other changes, beyond what are thus indicated are 
looked forward to. People, then, who had relied Anticipated 
with implicit faith on the modern astronomy, Ganges in 
having practical proof of it in the predictions of 
the almanacs- — forgetting, however, that the old astronomers, 
from Thales downwards, had in their way foretold eclipses, and 
that certain lunar calculations are still made on the Ptolemaic 
hypothesis — are waiting for the revelations of the next transits 
of* Menus. 
The position is this : we have been told that the reduc- 
tion of our distance from the sun, as mathematically estimated, 
changes the circumference previously assigned to our orbit by 
twenty-six millions three hundred and sixty thousand miles ; 
our mean hourly velocity being also less by sixty-five thousand 
four hundred and sixty miles than previously determined. 
We are assured that the diameter of the sun is really less by 
thirty-eight thousand miles than the books told : us ten years 
since ; and that the velocity of light is less by eight thousand 
miles per second than previous calculations had reckoned ; and 
as the astronomers were trusted before, they must be now T . 
The distances, velocities, and dimensions of the whole plane- 
tary system, when revised by them on this basis, must, how- 
ever, await the further disturbances. We remember with 
VOL. vi. 2 4 
