Note 1 — Chapter III

In connection with this discussion it is to be remembered that nearly two centuries were required for the Copernican system, promulgated in 1543, in the De orbium coelestium revolutionibus, to become generally popularized; and that in 1633, only sixteen years before the Voyage to the Moon was written, Galileo had been compelled by the Inquisition to deny the motion of the earth.