There is probably no other machine used by mankind, with the possible exception of the watch, that does service to such a variety of individuals as the cycle. Now, it would be of little use to write a book for popular reading on the mechanical construction of a watch, because from its very nature none but an expert could appreciate the facts, if any were given; but greater hope might be entertained in regard to a larger machine, because the buyer can at least see what he is about. You never heard of a bicycle-rider blaming his repairer for stealing the wheels out of his machine and substituting others, because he can see, however inexperienced he may be, that this has not been done. Now, if we all could, by a little observation, learn one-half as much about our watches as we can about our bicycles, the poor watch-maker would never suffer the indignities so universally and unjustly heaped upon him. The primary knowledge above hinted at as possible, among the hoped-for patrons of this work, seems to be an auspicious circumstance in connection with an effort to teach them a little more. CHAPTER III. CAN WE IMPROVE UPON THE CREATOR’S METHODS? “We find in a great number of standard treatises a sort of accusation brought against nature for having entirely wasted a great part of the force of our muscles by causing them to act under a disadvantageous leverage.”—+E. J. Marey.+[1] À propos of fundamental principles, what are the requirements needful for the most successful means of man-motor locomotion? In more homely phrase, how can a man, without calling upon the storage of energy other than that inherent in his own body, propel himself from place to place with the least amount of physical exertion? It is evident now, that under very many circumstances the means provided us by the Creator for such purposes are not the most economical; that is to say, it has been found that if we employ a medium through which to transmit our energy, the energy will be more economically expended, in carrying our bodies from place to place, than if we apply the force directly to the work as nature seemed to intend in presenting us with a pair of legs. The writer cheerfully concedes, for one, that for almost all purposes the legs are very practical; as, for instance, in climbing a tree or a pair of stairs, a rail fence, or even a very steep hill, or when, as in some of our early travels, we are compelled by an embarrassing paucity of funds to take to the cross-ties of a poorly ballasted railroad. And further, we admit that the invention of a pair of legs, if properly claimed in a patent, would, with perfect justice, have entitled the inventor to all uses to which they could be put, including the pumping of a bicycle. But we are perfectly willing to infringe the leg patent, provided we can improve upon it even for certain purposes, as we have in adopting the modern bicycle, in its use, for instance,