“Among the many objections to high speed, we are often told that the beam-engine will not bear it, and the beam-engine, sir, was designed by Watt. In reverence for that great name, we yield to no one. The beam-engine, in its adaptation to the conditions under which it was designed to work--namely, a piston speed of 220 feet per minute and a pressure of one or two atmospheres--was as nearly perfect as any work of human skill ever was or will be; but we wonder why the outraged ghost does not haunt the men who cling to the material form they have inherited, when the conditions which it was designed to meet have been all outgrown, who have used up his factor of safety, and now stand among their trembling and breaking structures, deprecating everything which these will not endure. “A journal and its bearings ought not only never to become warm, but never even to wear, and, if properly made, never will do so with ordinary care to any appreciable extent, no matter how great speed is employed. It is well known that there exists a very wide difference in bearings in this respect, some outlasting dozens of others. Now, there need be no mystery about this: the conditions of perfect action are so few and simple that it seems almost idle to state them. The first is rigidity of a shaft or spindle between its bearings; but everybody knows that if this is flexible, just in the degree in which it springs, the journals must be cast in their bearings, though in actual practice this perfect rigidity is not once in a thousand times even approximated to. The point of excellence in the celebrated Sellers bearing for shafting is that it turns universally to accommodate itself to this flexure of the shaft, and the result is a durability almost perfect. “The second requirement, when we have a shaft capable of maintaining perfect rigidity under all the strains it may be subjected to, is abundant extent of bearing surface both in length and circumference, a requirement, it will be seen, entirely consistent with the first. It is a mistake to use journals of small diameter with the idea that their enlargement will occasion loss of power on account of the increased surface velocity, as, in fact, the coefficient of friction will diminish in a greater ratio than that in which the velocity is increased. In the Allen engine it is intended to make all shafts and journals too large.