In this moment of peril I did not forget my mathematics.

It was clear that if the giant propelled me with sufficient velocity I should be shot into space, never to return.

How great would that velocity have to be?
My mind worked like lightning on this problem.
The diameter of Menippe I knew did not exceed twelve miles.

Its mean density, as near as I could judge, was about the same as that of the earth.

Its attraction must therefore be as its radius, or nearly 660 times less than that of the earth.