Whether the steam engine has reached its climax, and gas, oil, or other agents are to be used extensively for power, in the near future, is a question now debated in scientific circles. Much progress has been made in using these substitutes, and more is probable, as one obstacle after another is overcome. Gas especially is coming forward, and oil is freely used. For reasons before stated, it seems to the writer that, where coal is plentiful, the day is distant when steam will not continue to be the principal source of power. It will be a world surpriser that beats one horse-power developed by one pound of coal. The power to do much more than this, however, lies theoretically in gas, but there come these wise words of Arago to mind: "Persons whose whole lives have been devoted to speculative labours are not aware how great the distance is between a scheme, apparently the best concerted, and its realisation." So true! Watt's ideas in the brain, and the steam engine that he had to evolve during nine long years, are somewhat akin to the great gulf between resolve and performance, the "good resolution" that soothes and the "act" that exalts. The steam engine is Scotland's chief, tho not her only contribution to the material progress of the world. Watt was its inventor, we might almost write Creator, so multiform were the successive steps. Symington by the steamship stretched one arm of it over the water; Stephenson by the locomotive stretched the other over the land. Thus was the world brought under its sway and conditions of human life transformed. Watt and Symington were born in Scotland within a few miles of each other. Stephenson's forbears moved from Scotland south of the line previous to his birth, as Fulton's parents removed from Scotland to America, so that both Stephenson and Fulton could boast with Gladstone that the blood in their veins was Scotch. The history of the world has no parallel to the change effected by the inventions of these three men. Strange that little Scotland, with only 1,500,000 people, in 1791, about one-half the population of New York City, should have been the mother of such a triad, and that her second "mighty three" (Wallace, Bruce and Burns always first), should have been of the same generation, working upon the earth near each other at the same time. The Watt engine appeared in 1782; the steamship in 1801; the locomotive thirteen years later, in 1814. Thus thirty-two years after its appearance Watt's steam-engine had conquered both sea and land.