“The advantages of more rapid rotation are largely felt in the transmission of power. Engineers understand very well that, theoretically, the prime mover should overrun the resistance. Motion should be not multiplied but reduced in transmission. This can seldom be attained in practice, but high speed gives the great advantage of an approximation to this theoretical excellence. On the other hand, slow-speed engines work against every disadvantage. Coupled engines and enormous fly-wheels have to be employed to give a tolerably uniform motion; often great irregularities are endured, or the abominable expedient is resorted to of placing the fly-wheel on the second-motion shaft. Then comes the task of getting up the speed, with the ponderous gearing and the enormous strains. Slow motion also prevents the use of the belt, immeasurably the preferable means of communicating power from a prime mover. “But how about the wear and tear? The question comes from friends and foes alike. The only difference is in the expression of countenance, sympathetic or triumphant. The thought of high speed brings before every eye visions of hot and torn bearings, cylinders and pistons cut up, thumps and breakdowns, and engines shaking themselves to pieces. It is really difficult to understand how so much ignorance and prejudice on this subject can exist in this day of general intelligence. The fact is, high speed is the great searcher and revealer of everything that is bad in design and construction. The injurious effect of all unbalanced action, of all overhanging strains, of all weakness of parts, of all untruth in form or construction, of all insufficiency of surface, increases as the square of the speed. Put an engine to speed and its faults bristle all over. The shaking drum cries, ‘Balance me, balance me!’ the writhing shaft and quivering frame cry, ‘See how weak we are!’ the blazing bearing screams, ‘Make me round!’ and the maker says, ‘Ah, sir, you see high speed will never do!’ “Now, nothing is more certain than that we can make engines, and that with all ease, in which there shall be _no_ unbalanced action, _no_ overhanging strains, _no_ weakness of parts, _no_ untruth of form or construction, _no_ insufficiency of surface; in which, in short, there shall be _no_ defect to increase as the square of the speed, and then we may employ whatever speed we like. ‘But that,’ interposes a friend, ‘requires perfection, which you know is unattainable.’ No, we reply, nothing unattainable, nothing even difficult, is required, but only freedom from palpable defects, which, if we only confess their existence, and are disposed to get rid of, may be easily avoided. It is necessary to throw all conceit about our own work to the dogs, to lay down the axiom that whatever goes wrong, it is not high speed, but ourselves who are to blame, and to go to high speed as to our schoolmaster.