Until this week we did not see a short article published in a monthly magazine in this city a month ago, by one signing himself W. B. S.. of Boston, wherein he states " the Editor of the Scientific American misunderstood Mr. Clark's meaning about the effects of the earth's rotation on locomotion." He, it seems, understands Mr. Clark's meaning to a diamond shaving, and~Tiere'ifiTir~HB says, "If the engine is running north from one place to another at which the rotative velocity is less, the engine will have a greater rotative velocity than the portions of the track with which it comes in contact, and will therefore exert a slight but imperceptible lorce against the easterly or right hand rail. On the return of the engine the rotative velocity of the track will be greater than that of the engine, hence the engine will now press the westerly or right hand rail, with a force equal to the difference between the rotative velocity of the track and that of the engine." This explanation is certainly made in accor dance with that rule, which works both ways, an exceedingly convenient one for superficial reasoners. By this logic, when the locomotive is running to the north and parting at every point of its journey with increments ol rotative force, the said engine climbs the right hand rail in the direction of the earth's rotation, but when the locomotive is coming back on the same road, and is receiving increments of rotative force at every advancing point (in the same direction as before,) it climbs the opposite rail. That is, the effect of the earth's rotation on a locomotive causes it to climb the rail to one side while travelling in oae direction, and the opposite rail when travelling in the contrary direction. We contess that this is not an exhibition of the effect of the earth's rotation on locomotion, but the effect of locomotion on the earth's rotation.mdash; The earth keeps rotating in the same direction, but this critic, who understands Mr. Clark's meaning so well, makes his locomotive act with and against the earth's rotation, just by moving backwards and forwards.