A similar condition holds with regard to space-distortion. The Theory of Relativity enforces the conclusion that from the standpoint of our conventions in regard to these matters, all bodies involved in transportation undergo a contraction in the direction of that transportation, while their dimensions perpendicular to the transportation remain invariable. This contraction is the same for all bodies. For bodies of low velocity, like the earth, this distortion would be almost immeasurably slight; but great or little, no measuring instruments on the body transporting would ever disclose it, for a measure would undergo the same contraction as the thing measured. THE SPOON-MAN These concepts that space and time are not as immutable as they appear: that our universe may suffer distortion, that time may lag or hasten without our being in the least aware, may be made interestingly clear by an illustration first suggested by Helmholtz, of which the following is in the nature of a paraphrase. If you look at your own image in the shining surface of a teapot, or the back of a silver spoon, all things therein appear grotesquely distorted, and all distances strangely altered. But if you choose to make the bizarre supposition that this spoon-world is real, and your image--the spoon-man--a thinking and speaking being, certain interesting facts could be developed by a discussion between yourself and him. You say, "Your world is a distorted transcript of the one in which I live." "Prove it to me," says the spoon-man. With a foot-rule you proceed to make measurements to show the rectangularity of the room in which you are standing. Simultaneously he makes measurements giving the same numerical results; for his foot-rule shrinks and curves in the exact proportion to give the true number of feet when he measures his shrunken and distorted rear wall. No measurement you can apply will prove you in the right, nor him in the wrong. Indeed he is likely to retort upon you that it is your room which is distorted, for he can show that in spite of all its nightmare aspects his world is governed by the same orderly geometry that governs yours. The above illustration deals purely with space relations, for such relations are easily grasped; but certain distortions in time relations are no less absolutely imperceptible and unprovable. So far from having any advantage over the spoon-man, our plight is his. The Principle of Relativity discovers us in the predicament of the Mikado's "prisoner pent," condemned to play with crooked cues and elliptical billiard balls, and of the opium victim, for whom "space swells" and time moves sometimes swift and sometimes slow. THE ORBITAL MOVEMENT OF TIME