224 
THE LIGHT-RECORD OF THE PAST. 
1,120 feet per second). If the speed of the sentient bullet could 
be augmented so as to exceed that of light, then it would proceed on 
its way wholly unconscious (so far as the senses of seeing and of 
hearing are concerned) of the fact of its having been fired off. 
In the force of gravity we have an example of a force whose 
velocity must be very much greater (perhaps a million times) than 
that of light. Let us imagine a living being—a human bullet— 
to be projected outward from the earth with the velocity of gravity ; 
such a traveller would (like all modern tourists), of course, carry 
with him a photographic camera of the latest type. 
As the wanderer receded from the earth he would overtake the 
rays of light, and they would reveal to him the history of the past 
in the most striking manner. But there would be no field for the 
exercise of the deductive faculties, for the effect would 'precede the 
cause. 
Arriving at a distance from the earth equal to that of the sun, 
we should see things on the earth just as they were 8J minutes 
before we started ; while on the confines of the solar system this time 
would be extended to four hours. 
But it would be when our journey was extended to the fixed 
stars that the most striking results would be obtained. Light 
takes about four years to travel from the earth to the nearest fixed 
star; so that at this moment* a photographic observer near that 
star, being provided with a sufficiently sensitive dry-plate, could 
photograph, say, the brilliant scenes attending the visit of the Shah 
of Persia to this country in 1889. 
Considering the brightest fixed star, Sirius—the Dog-star—we 
know that if this “giant sun” were suddenly extinguished we 
should not be made aware of the fact for eighteen years ; for light 
takes that length of time to travel from Sirius to the earth. And, 
vice-versa , an observer stationed on one of the mighty planets which 
—though as yet invisible to us—all analogy teaches us to believe 
are circling round Sirius, would at this moment see things on 
the earth as they were in the year 1875. So that in the case of a 
man who married at thirty, and who is now forty-eight years of 
* I write this in September, 1893. 
Octobeu, 1893. 
