To this habit of continuity of attention, tracing the first simple idea to its remoter consequences, the philosophical genius owes many of its discoveries. It was one evening in the cathedral of Pisa that GALILEO observed the vibrations of a brass lustre pendent from the vaulted roof, which had been left swinging by one of the vergers. The habitual meditation of genius combined with an ordinary accident a new idea of science, and hence conceived the invention of measuring time by the medium of a pendulum. Who but a genius of this order, sitting in his orchard, and observing the descent of an apple, could have discovered a new quality in matter, and have ascertained the laws of attraction, by perceiving that the same causes might perpetuate the regular motions of the planetary system; who but a genius of this order, while viewing boys blowing soap-bladders, could have discovered the properties of light and colours, and then anatomised a ray? FRANKLIN, on board a ship, observing a partial stillness in the waves when they threw down water which had been used for culinary purposes, by the same principle of meditation was led to the discovery of the wonderful property in oil of calming the agitated ocean; and many a ship has been preserved in tempestuous weather, or a landing facilitated on a dangerous surf, by this solitary meditation of genius. Thus meditation draws out of the most simple truths the strictness of philosophical demonstration, converting even the amusements of school-boys, or the most ordinary domestic occurrences, into the principle of a new science. The phenomenon of galvanism was familiar to students; yet was there but one man of genius who could take advantage of an accident, give it his name, and fix it as a science. It was while lying in his bath, but still meditating on the means to detect the fraud of the goldsmith who had made Hiero's crown, that the most extraordinary philosopher of antiquity was led to the investigation of a series of propositions demonstrated in the two books of ARCHIMEDES, _De insidentibus in fluido,_ still extant; and which a great mathematician admires both for the strictness and elegance of the demonstrations. To as minute a domestic occurrence as GALVANI'S we owe the steam-engine. When the Marquis of WORCESTER was a State prisoner in the Tower, he one day observed, while his meal was preparing in his apartment, that the cover of the vessel being tight, was, by the expansion of the steam, suddenly forced off, and driven up the chimney. His inventive mind was led on in a train of thought with reference to the practical application of steam as a first mover. His observations, obscurely exhibited in his "Century of Inventions," were successively wrought out by the meditations of others, and an incident, to which one can hardly make a formal reference without a risible emotion, terminated in the noblest instance of mechanical power.