40 THE HAMILTON ASSOCIATION. 
number can alone be reckoned in the arithmetic of heaven, this fair 
daughter born of her Earth-mother will in a long, circling spiral come 
back again and gently, like a fallen blossom from one of Earth’s 
flowers, fall back on the bosom of her parent not with a crash of 
colliding spheres and the heat of riven globes, but softly make her 
grave where her cradle was in the long ago past. 
The effect, therefore, of solar tidal friction is to retard the revolu- 
tion of the Earth while the revolution of the Moon in her orbit will 
increase. Until recently no casefof a satellite having a less period 
than its planet's rotation appeared to exist, and it was therefore 
argued that the theory was unsound, as not being berne out any- 
where in visible nature. But in 1877, Professor Asaph Hall dis- 
covered two satellites of our neighbor Mars, which he named 
Phobos and Deimos—Fear and Panic, the dogsof war. The period 
of Deimos is about thirty hours, and that of Phobos something less 
than eight hours, while the Martian day is something like twenty-four 
hours. Here then is an illustration of the future condition of our 
Earth-Moon system for the solar tidal friction having such an effect 
upon Mars which is so much nearer the Sun than our Earth has 
slowed him down so that Fear circles him round nearly three times 
every day, which would surely be enough to drive all the warlike 
spirit out of him. The ultimate fate of this satellite will therefore be 
absorption into his planet. The Mars-Phobos system is therefore 
further advanced and it will remain for astronomers in coming cen- 
turies to discern any approach of Phobos to his parent Mars. 
If Darwin’s theory be true we would naturally turn to Mercury 
and Venus and see what effect solar tidal friction has had on their 
rotation periods. As the solar-tide raising force varies inversely as 
the cube of the distance of the planets, these solar tides are far 
greater on Mercury and Venus than on our Mother Earth. Although 
younger in point of years than Terra, as indeed would become the 
Queen of Beauty and the swift-footed messenger of the gods, yet as 
Sun-plant systems they are older because their gradations are far- 
ther advanced. It would therefore be reasonable according to the 
theory that we are investigating that the immense solar tides must 
have diminished their periods of rotation that they are united as at 
the end of a bar with the Sun as obtains in our Earth-Moon system 
and so like loyal courtiers they keep their faces always turned to the 
