Synonyms for motive power

What is it originates, directs, and controls the motive power?

Any one of them, Carpenter said, was ample for motive power.

And when did he learn to use the tree-tops for his swing and the wind for his motive power?

But you've got to admit that they haven't got either the motive power or the money.

In your motive power see to it there is no mixture of vanity with duty.

A few years ago the motive power for most manufactures was steam.

We turn on the motive power, and it moves at the rate of a mile a minute if we desire it.

This was purchased as being exactly the motive power required.

Culture is the end of life, the spirit of service the motive power.

Of course it is quite impossible that the motive power can be electricity?