Present two smooth pieces of marble to a man who has no tincture of natural philosophy; he will never discover that they will adhere together in such a manner as to require great force to separate them in a direct line, while they make so small a resistance to a lateral pressure.
Filosofia naturalari buruz tutik ez dakien gizakume bati eman bi haitzurdin-zati leun eta ezetz inoiz atera hala elkarri itsasten direla, non apartatzeko indar izugarria behar den zuzenetara, albo-presioari ordea aise amore ematen diotela.