104 
A. COTTAM-MODEL OF THE SOLAR SYSTEM. 
discovered that the distances between the orbits of the planets 
followed a regular order, each succeeding planet proceeding out¬ 
wards from the Sun being very nearly double the distance of the 
last—with one exception—and that was Jupiter, whose distance, 
instead of being twice the distance of Mars, is nearly four times 
that distance. And Kepler prophesied that some day a planet 
would be discovered occupying this vacant place. The progression 
is not exact, but Bode discovered a curious empyrical law, which 
represents the distances with remarkable exactness, the fifth space 
being blank. It will be noticed that Uranus, which was not dis¬ 
covered till long after Bode discovered this remarkable series, fits 
in very well with the theory. Hot so, however, Neptune, whose 
distance is much less. The probability that a planet would be 
found to occupy the vacant place became, as time went on, more 
and more firmly fixed in the minds of astronomers, and in 1800 six 
distinguished observers, after discussing the matter, resolved to 
make a persevering search. Piazzi of Palermo, one of the six, 
discovered, on the 1st January, 1801, a small star in Taurus, which 
in the course of two or three evenings’ observation was found to 
be moving; its orbit was calculated after a time and it was dis¬ 
covered to occupy exactly the position that Kepler had prophesied 
200 years before would be found to be filled by a planet. This 
new planet was called Ceres. The chief peculiarity of this planet 
was its minute size. It is probably about 300 miles only in dia¬ 
meter. Two years afterwards Dr. Olbers at Bremen discovered 
another small planet, with a distance and time almost identical 
with those of Ceres. In fact the orbits intersect each other. This 
was called Pallas, and Olbers suggested that they were portions of 
a large planet that by some convulsion had been rent asunder. The 
idea led to a continuance of the search. Juno was discovered in 
1804, and in 1807 Vesta, both revolving in orbits close to those of 
Ceres and Pallas. For nearly 40 years no more were discovered, 
but in 1845 a fifth was found, and from that time to the present 
some have been found almost every year, until at the present time 
there are no less than 252 of these small planets known, revolving 
in orbits between Mars and Jupiter. A 
Although the subject of this paper is the Solar System, it may 
be interesting to say a few words about the so-called fixed-stars, of 
which our Sun is one. We have seen that upon the scale of 10,000 
miles to an inch a model of our system would occupy a space over 
9 miles in diameter, and it may be interesting to enquire how far off 
from our model Sun we should have to place the nearest of the 
fixed-stars. There is no place on this Earth far enough off. The 
distance of the nearest star is about 30,000,000,000,000 of miles, 
which would be represented in our model by a distance of over 
47,000 miles, or nearly one-fifth of the distance from us to the Moon. 
