The Southward attraction in our country is so slight that even to a woman my tale necessarily appeared extraordinary and well-nigh incredible; but my wife, whose good sense far exceeds that of the average of her sex, and who perceived that I was unusually excited, did not argue with me on the subject, but insisted that I was ill and required repose. I was glad of an excuse for retiring to my chamber to think quietly over what had happened. When I was at last by myself, a drowsy sensation fell on me; but before my eyes closed I endeavoured to reproduce the Third Dimension, and especially the process by which a Cube is constructed through the motion of a Square. It was not so clear as I could have wished; but I remembered that it must be “Upward, and yet not Northward,” and I determined steadfastly to retain these words as the clue which, if firmly grasped, could not fail to guide me to the solution. So mechanically repeating, like a charm, the words, “Upward, yet not Northward,” I fell into a sound refreshing sleep.