"Ah, there we are through the clouds again.

What makes us rise?
Is that the force that Pop told me he discovered ?" "I'll answer the last question first," said Redgrave.

"That was the greatest of your father's discoveries.

He got at the secret of gravitation, and was able to analyse it into two separate forces just as Volta did with electricity--positive and negative, or, to put it better, attractive and repulsive.
"Three out of the five sets of engines in the _Astronef_ develop the R.
Force, as I call it for short.

This wheel with the hundred degrees marked behind it regulates the development.