Sir Robert S. Ball has given a very marked illustration of the wonderful magnitude of space in his late book entitled “In the High Heavens,” from which we quote as follows: “Summon up to your imagination the most distant star that can be seen with the unaided eye. Then think of the minutest star that our most potent telescope can disclose. Think of the tiniest stellar point of light which could possibly be depicted on the most sensitive photographic plate after hours of exposure to the heavens. Think, indeed, of the very remotest star which, by any conceivable device, can be rendered perceptible to our consciousness. Doubtless that star is thousands of billions of miles from earth; doubtless the light from it requires thousands of years, and some astronomers have said millions of years, to span the abyss which intervenes between our globe and those distant regions. But, nevertheless, there is a certain number of miles, even though we know it not, at which the remotest stars known to us must lie. I do not speak of the most distant star which the universe may possibly contain; I only refer to the most distant star that we can possibly bring within our ken. Imagine a great sphere to be described with its centre at our earth, and with a radius extending all the way from the earth to this last star knowable by man. Every star that we can see, every star whose existence becomes disclosed to us on our photographs, lies inside this sphere; as to the orbs which may lie outside that sphere we can know nothing by direct observation. The imagination doubtless suggests with irresistible emphasis, that this outer region is also occupied by stars and nebulae, suns and worlds, in the same manner as the interior of that mighty sphere whose contents are more or less accessible to our scrutiny. It would do utter violence to our notions of the law of continuity to assume that all the existent matter in the universe happened to lie inside this sphere; we need only mention such a supposition to dismiss it as wholly indefensible. I do not now make any attempt to express the number of miles in the diameter of the sphere which limits the extent of space known directly to man. What that number may be is quite immaterial for our present purpose. But the point that I especially want to bring out is that the volume occupied by this stupendous globe, which includes within it all possible visible material, must be but a speck when compared with the space which contains it. Think of the water in the Atlantic Ocean, and think of the water in a single drop. As the drop is to the Atlantic Ocean so is the sphere which we have been trying to conceive to the boundless extent of space. As far as we know it would seem that there could be quite as many of such spheres in space as there are drops of water in the Atlantic Ocean.”