It seems superfluous at this stage of development of the art to enlarge upon the fact that a bicycle has to be balanced by a particular action not required in any other form of carriage; but when inventors will keep on getting up means to lock the steering device, and riders will persist in reminding us that the steering head “moves too easily,” it is severely pertinent to remark that while a certain law of whirling bodies might show us that a wheel will not fall over quite so quickly when rolling as when standing still, yet it is not this law so much as the action of steering that differentiates the bicycle, or single-track carriage, from other machines. The action of the handle-bar while in motion does substantially, in balancing the bicycle, what you would do if you were balancing a cane vertically on the end of your nose: if the cane starts to fall, you run in that direction with your nose till you get under the centre of gravity again. But the bicycle can only fall sideways, so, when it tends to fall in that way, or when the centre of gravity gets to one side of the vertical line from the point of support on the ground, you cannot run directly sideways with the support as you would in the cane illustration, but you can run indirectly sideways, nevertheless, with the point of support, the only difference being that you must run considerably forward at the same time in order to shift the lower extremity, or point of contact and support, in that direction. After considerable discussion of this apparently simple subject with eminent gentlemen well qualified to speak on such topics, the following appeals to my mind as a more definite and complete explanation than that given in the nose and cane case, bringing in an element of the problem omitted above, to wit: in running the point of support of contact across and under, as it approaches the vertical plane of gravity and general forward momentum, the steering wheel lies slightly across this plane, and its own plane is still out of vertical, leaning a little, as it did before, with the centre of gravity back of the point of support; the forward momentum then throws the entire system upright. In rapid running this momentum does a large proportion of the work, and it has been vigorously maintained that all balancing is due to this element; for small motions, however, the cane explanation is quite sufficient. The foregoing explanation of uprighting the bicycle is, to my mind, almost _entirely_ independent of any law of whirling bodies as generally understood.