PENSTOCKS AND TURBINES
As we descend now and reach at last the lowest floor of the building, we step out into a long narrow room, the main surface of which is taken up with a series of gigantic turnip-shaped mechanisms, each one having a revolving shaft at its axis; while from its side projects outward and then upward a seven-foot steel tube, for all the world like the funnel of a steamship. This seeming funnel—technically termed a penstock—is in reality the great tube through which the massive column of water finds access to the turbine wheel, which of course is incased within the turnip-shaped mechanism at its base.
As you stand there beside this great steel mechanism a sense of wonderment and of utter helplessness takes possession of you. As you glance down the hall at this series of great water conduits, and strain your eyes upward in the endeavor to follow the great funnel to its very end, an oppressive sense of the irresistible weight of the great column of water it supports comes to you, and you can scarcely avoid a feeling of apprehension. Suppose one of the great tubes were to burst?—we should all be drowned like rats in a hole. There is small danger, to be sure, of such a contingency; but it is well worth while to have stood thus away down here at the heart of the great power-house to have gained an awed sense of what man can accomplish toward rivaling the wonders of nature. To have stood an hour ago on the ice bridge at the foot of the most tremendous cataract in the world, where Nature exhausts her powers amidst the mad rush and roar of seething waters; and now to stand beneath this other column of water which effects a no less wonderful transformation of energy, serenely, silently,—is to have run such a gamut of emotions as few other hours in all your life can have in store for you.