Page:The evolution of worlds - Lowell.djvu/285

Rh If, however, the bodies were all moving in the same sense as the Earth, i.e. direct, the ratios would be:—

As the actual number encountered is between 2 and 3 to 1, we see that the greater part must be travelling in the same sense as the Earth, since they come indifferently at all altitudes from the plane of her orbit.

2

The densities of the principal planets, so far as we can determine them at present, the density of water being unity, are:—

The second decimal place is not to be considered as anything but an indication.

3

In the case of a body reflecting light, the shift differs from that for a body emitting it. If the planet be on the