ernie, the second one does actually make sense but it has been misquoted over time.
How is a mouse when it spins? – The higher, the fewer.
The meaning had to do with the centrifugal governor on an old steam engine – the weight was called the mouse, and as the engine rpm increased the mouse would rise due to centrifugal force. But as the mouse rose, the arm would force the steam valve in the more closed direction, thus reducing the rpm, that is, the higher (the mouse), the fewer (rpms). So for a given setting of the mouse on the arm, the engine would run
at a constant speed.
The elephant joke, I can't explain. 🙂