You will see America across the Atlantic and Japan across the Pacific; but you cannot see, in one single effort of the imagination, an Atlantic of empty blue water stretching to an empty horizon, another beyond that equally vast and empty, another beyond that, and so on until you have spanned the thousand horizons that lie between England and America.

The mind, that is to say, works in steps and spans corresponding to the spans of physical sight; it cannot clear itself enough from the body, or rise high enough beyond experience, to comprehend spaces so much vaster than anything ever seen by the eye of man.

So also with the stretching of the horizon which bounded human knowledge of the earth.

It moved step by step; if one of Prince Henry's captains, creeping down the west coast of Africa, discovered a cape a hundred miles south of the known world, the most he could probably do was to imagine that there might lie, still another hundred miles farther south, another cape; to sail for it in faith and hope, to find it, and to imagine another possibility yet another hundred miles away.

So far as experience went back, faith could look forward.