Ever since celestial mechanics in the skillful hands of Leverrier and Adams led to the world-amazed discovery of Neptune, a belief has existed begotten of that success that still other planets lay beyond, only waiting to be found.

Are physical forces alone at work there, or has evolution begotten something more complex, something not akin to what we know on Earth as life? It is in this that lies the peculiar interest of Mars.

There are celestial sights more dazzling, spectacles that inspire more awe, but to the thoughtful observer who is privileged to see them well, there is nothing in the sky so profoundly impressive as the canals of Mars. Fine lines and little gossamer filaments only, cobwebbing the face of the Martian disk, but threads to draw one's mind after them across the millions of miles of intervening void.

Imagination is as vital to any advance in science as learning and precision are essential for starting points. Let me warn you to beware of two opposite errors: of letting your imagination soar unballasted by facts, but on the other hand, of shackling it so solidly that it loses all incentive to rise.

Imagination is as vital to any advance in science as learning and precision are essential for starting points.

Speculation has been singularly fruitful as to what these markings on our next to nearest neighbor in space may mean. Each astronomer holds a different pet theory on the subject, and pooh-poohs those of all the others. Nevertheless, the most self-evident explanation from the markings themselves is probably the true one; namely, that in them we are looking upon the result of the work of some sort of intelligent beings. . . . The amazing blue network on Mars hints that one planet besides our own is actually inhabited now.

Now when we think that each of these stars is probably the centre of a solar system grander than our own, we cannot seriously take ourselves to be the only minds in it all.