When the heart of the woolspinner of Genoa was sickening with “hope deferred,” and his men, who had long been straining their eyes in vain to catch a glimpse of land, were about to burst into open mutiny, and were shouting fearfully to their leader to steer the vessel back again, Columbus picked up a piece of wood which he found floating upon the waters. The shore must be nigh, he thought, from whence this branch has wafted, and the inference inspired the fainting hearts of his crew to persevere and gain the hoped-for land; had it not been for this trifling occurrence, Columbus would perhaps have returned to Spain an unsuccessful adventurer. But such trifles have often befriended genius. Accidentally observing a red-hot iron become elongated by passing between iron cylinders, suggested the improvements effected by Arkwright in the spinning machinery. A piece of thread and a few small beads were means sufficient in the hands of Ferguson, to ascertain the situation of the stars in the heavens. The discovery of Galvani was made by a trifling occurrence; a knife happened to be brought in contact with a dead frog which was lying upon the board of the chemist’s laboratory, the muscles of the reptile were observed to be severely convulsed—experiments soon unfolded the whole theory of Galvanism. The history of the gas-light is curious, and illustrates our subject. Dr. Clayton distilled some coal in a retort, and confining the vapor in a bladder, amused his friends by burning it as it issued from a pin-hole; little did the worthy doctor think to what purposes the principle of that experiment was capable of being applied. It was left for Murdoch to suggest its adoption as a means of illuminating our streets and adding to the splendor of our shops. Had Clayton not made known his humble experiment, we probably should still be depending on the mercy of a jovial watchman for a light to guide us through the dark thoroughfares of the city, or to the dim glimmer of an oil lamp to display the luxury of our merchandise.