All the performances of human art, at which we look with praise or wonder, are instances of the resistless force of perseverance: it is by this that the quarry becomes a pyramid, and that distant countries are united with canals. If a man was to compare the effect of a single stroke of the pick-ax, or of one impression of the spade with the general design and last result, he would be overwhelmed by the sense of their disproportion; yet those petty operations, incessantly continued, in time surmount the greatest difficulties, and mountains are levelled, and oceans bounded, by the slender force of human beings.