speed of 30 kilometers (better
29-1/2) per second, or 1,770 kilometers per minute, or 106,000
kilometers per hour, or 2,592,000 kilometers per day, or 946,080,000
kilometers (586,569,600 miles) in the year. This is the length of the
elliptical path described by the Earth in her annual translation.

The length of orbit being thus discovered, one can calculate its
diameter, the half of which is exactly the distance of the Sun.

We may cite one last method, whose data, based upon attraction, are
provided by the motions of our satellite. The Moon is a little disturbed
in the regularity of her course round the Earth by the influence of the
powerful Sun. As the attraction varies inversely with the square of the
distance, the distance may be determined by analyzing the effect it has
upon the Moon.

Other means, on which we will not enlarge in this summary of the methods
employed for determinations, confirm the precisions of these
measurements with certainty. Our readers must forgive us for dwelling
at some length upon the distance of the orb of day, since this
measurement is of the highest importance; it serves as the base for the
valuation of all stellar distances, and may be considered as the meter
of the universe.

This radiant Sun to which we owe so much is therefore enthroned in space
at a distance of 149,000,000 kilometers (93,000,000 miles) from here.
Its vast brazier must indeed be powerful for its influence to be exerted
upon us to such a manifest extent, it being the very condition of our
existence, and reaching out as far as Neptune, thirty times more remote
than ourselves from the solar focus.

It is on account of its great distance that the Sun appears to us no
larger than the Moon, which is only 384,000 kilometers (238,000 miles)
from here, and is itself illuminated by the brilliancy of this splendid
orb.

No terrestrial distance admits of our conceiving of this distance. Yet,
if we associate the idea of space with the idea of time, as we have
already done for the Moon, we may attempt to picture this abyss. The
train cited just now would, if started at a speed of a kilometer a
minute, arrive at the Sun after an uninterrupted course of 283 years,
and taking as long to return to the Earth the total would be 566 years.
Fourteen generations of stokers would be employed on this celestial
excursion before the bold travelers could bring back news of the
expedition to us.

Sound is transmitted through the air a