We did not experience from Mercury the same vigorous rivalry in the new navigation as had come to us from Venus. The rule bore here, as it is inferred to do in general, that the stronger the solar light, the less does business, and the more does science and other such high consideration, influence the mind and purpose. It was ever, at bottom, business purposes and business prospects that supplied the chief vigour to our progress. Mercury was comparatively deficient in this kind of vigour, and more addicted to purely scientific and other mental progress, carried on independently for its own sake.
Let me only add, in conclusion, that we have, since these earlier efforts, successively reached all the members of our system, even, many times over, to far outside Neptune, and even, some few times, at science's instance, to the smaller planet still outside of Neptune, and outside of all in the system, whose discovery dates only within the last thousand years, and whose remarkable conditions—the gathering up, as it were, of the outer margin of our original nebula, are already so well known to our science. So much for the outer voyaging, while inwards we have penetrated as far as the sun himself, as I shall have to tell further on. The interests of science, even with us Earthians, have at times risen above business considerations, seeing it is difficult to make a voyage to these far extremities, even to Neptune, or indeed even to Uranus, commercially profitable, in the want of human population in either planets or moons, to help us with their labour in the way that we find so advantageous with Mars, the First Jovian, and some others.
