x THE STARRY HEAVENS 893 
that there is water in Mars, and the two poles 
are tipped with white, as if capped by ice and 
snow. It presents also a series of remarkable 
parallel lines, the true nature of which is not 
yet understood. 
THE MINOR PLANETS -* 
A glance at Figs. 51 and 52 will show that 
the distances of the Planets from the Sun 
follow a certain rule. 
If we take the numbers 0, 3, 6, 12, 24, 48, 
96, each one (after the second) the double of 
that preceding, and add four, we have the 
series. 
: ok tee © 16 28 52 100 
Now the distances of the Planets from the 
Sun are as follow: — 
Mercury. Venus. Earth. Mars. Jupiter. Saturn. 
3.9 7.2 10. =—-15.2° 52.9 95.4 
For this sequence, which was first noticed 
by Bode, and is known as Bode’s law, no 
explanation can yet be given. It was of 
course at once observed that between Mars 
and Jupiter one place is vacant, and it has 
