Page:Popular Science Monthly Volume 11.djvu/168

156 But we have not touched bottom; and maybe these are some of His ways which are past finding out. So, having reached the deep waters, we will take that preacher's exordium to his knotty text, and make it the peroration of our discourse: "Brethren, there is mighty deep Scripture here!"



AST September, when the operations for the removal of the obstructions at Hell-Gate, in the harbor of New York, had culminated in the completion of the great labyrinth of tunnels, and the storing therein of a larger quantity of explosives than had ever been used at once before. General Newton, the chief-engineer, at the appointed moment told his little child to gently push a telegraph-key. She did so; her tiny impulse closed the circuit in many hundred galvanic cells; and these, by inflaming the metallic wires in contact with the explosives, freed in an instant the tremendous power which had been slumbering under the peaceful waters.

Perhaps in the whole realm of human achievement no more striking-example of an initiatory force has ever been given than this. And if it had not had an appearance of trifling, it would doubtless have been quite possible for matters to have been so arranged that a fly imprisoned in an inverted wineglass could by the vibration of its little wings have brought two delicate electric conductors into contact—say two moistened silken filaments—and have thus pulled the trigger which, in the course of its effects, would have made Hell-Gate navigable.

In Nature and art we find abundant examples of the same kind: gigantic forces, perfectly quiescent and even useless, until some slight additional force of the proper kind or intensity precipitates the most violent changes. And this necessity for an outside initiatory force is generally found with great power to maintain action once begun. Carbon, and fuels of all kinds, are instances in point. As a rule, they are but little altered by contact with the atmosphere, even for years; but a match has only to be applied to a few shavings, and a mine of coal may be set on fire so thoroughly that it continues burning for half a century. A prairie or forest may be dried up by drought until leaves and twigs are brittle and dead, but all is calm until a chance spark from a locomotive or a tobacco-pipe starts a fire that may devastate square leagues of territory in its course.

In all cases of unstable equilibrium—and such abound in Nature—a very small impetus may produce great consequences; and this not only in amount but direction. With an avalanche perched on a 