They traveled for several hours to a certain well, said to be more than three hundred feet deep, bored down through solid chalk. Hooke's mere appearance was enough to chase away the local farmers, who were only loitering and drinking anyway. He got Daniel busy constructing a solid, level platform over the mouth of the well. Hooke meanwhile took out his best scale and began to clean and calibrate it. He explained, 'For the sake of argument, suppose it really is true that planets are kept in their orbits, not by vortices in the æther, but by the force of gravity.'