And two hundred people pumped themselves into it, as air is forced into a pneumatic tyre.
Hang an empty "inner tube" of a pneumatic tyre over a nail and inflate it, and you will get a good illustration of the principle.
The action of the pneumatic tyre in reducing vibration and increasing the speed of a vehicle is explained by Figs. 166, 167.
When selecting an "outside" take care that you secure one equipped with a pneumatic tyre.