When I have been running hard and long, I feel myself perspiring like a bull and hot as a furnace.

Why am I then forced to stop?
Simply because my motion has been transformed into heat! Of course, I understand all about it!" Barbican smiled a moment at this comical illustration of his theory and then went on: "Accordingly, in case of a collision it would have been all over instantly with our Projectile.

You have seen what becomes of the bullet that strikes the iron target.

It is flattened out of all shape; sometimes it is even melted into a thin film.

Its motion has been turned into heat.