in this kingdom. There are sports that demand violent exertion spread over a short space of time; there are sports which are purely competitive, and have no attraction for the weakly; but cycling is a sport which combines the advantages of skill and strength, so that the physically weak man can often acquire sufficient skill to put him on a par with his more clumsy, if more muscular companion. In conclusion, I will only say how grateful I am to you for your kind attention, and, in the words of Sebastian in Twelfth Night, "I can no other answer make but thanks and thanks." Electric Traction. By M. HOLROYD SMITH, M.I.E.E., Introduction. It was with considerable hesitancy that I accepted the invitation of the Secretary of this institution to submit a paper on Electric Traction. So much is constantly appearing in the technical press on the subject that it is difficult, if not impossible, to add anything that is new and important; and I fear also the danger of being too simple and rudimentary, on the one hand, or too technical on the other. Though this Society cannot be regarded as a "popular audience," it may be safely assumed that only a few of my listeners are experts in electrical science, and they, I am sure, will pardon me if, for the benefit of those less favoured, I travel over well-known paths. Another reason for hesitation lies in the fact that it will be difficult for me to speak upon this subject without frequent reference to my own work, and on this account I must ask your indulgence. What electricity is it is impossible to say; we do not know, nor shall we ever know. Like the questions "What is life?" "What is matter?" it must remain unanswered; but, though we do not know what it is, we know many things about it, and are constantly learning more. We can produce VOL. XIII. * Read before the Society, on 23rd March 1891. R and measure it, direct and control it, and make it serve a hundred useful ends. To a novice it might seem that there was nothing in common between the attractive and repellent action of a piece of rubbed amber,—the northward pointing tendency of a steel needle after it had been rubbed with loadstone and the vivid flash of blinding light that precedes a thunder-clap; yet, this is so. They are all attributable to the same cause, that mysterious mode of motion which we call electricity. The great world itself may be regarded as a huge dynamo, and there is truth in the saying, "Electricity is life." Let us take one of these well-known facts, the mariner's compass, and see how far its action will enable us to understand an electric motor. A steel needle when rubbed with a loadstone becomes a magnet, and will attract other pieces of iron and steel; if allowed to swing free in space, it will turn one end northward and the other end southward. Bring two of these needles. together and it will be found that like poles repel, and opposite poles attract each other. All iron is slightly magnetic; all iron will become strongly magnetic if a current of electricity be made to pass round it. Take these few statements as the A B C, the leading principles, which, if fully realized, will enable us to understand an electric motor. As the terms "lines of magnetic force" are meaningless words to those unacquainted with electrical science, it will, perhaps, be well to try and explain what takes place by the use of mechanical terms and illustrations. Let A, fig. 1, represent a drum or barrel with two long cords wound round it, the end of one cord passing round the pulley in the box S, the end of the other round the pulley in the box N. Now, if weights be attached, these cords will be pulled off the drum, making it revolve. Notice, they are always pulling from the points n and s. This may be taken as illustrating the magnetic attraction. Referring to fig. 2, if A is a little water-wheel placed between two pipes, S and N, connected to a cistern full of water, and the water be allowed to flow from the spouts and impinge on the water-wheel, it would be forced round as long as the water supply lasted. This may be taken as illustrating the magnetic repulsion. If, now, we make the cistern a mass of iron and the pipes bars of iron wound with copper wire, and put heavy masses of iron at the bottom, shaped as shown at S and N in fig. 3, |