optician. Witness Sir William Herschel, who was a professional musician; Mr Ramage, who was a tanner in Aberdeen; Wx Lassels, who is a Liverpool merchant; Mr Nasmyth, an engineer; and, above all, Lord Rosse, who has carried the process of casting and polishing specula to such a pitch of refinement. Mr Clarke started in life as a printer, and afterwards took to portrait-painting, which he still practises to a certain extent, as a relaxation from his severer labours. It was not till he was upwards of forty years of age, that he turned his attention to telescopes. He was first attracted to the subject, by one of his boys asking his aid in casting a speculum for a small telescope, which he had taken a fancy to construct. From that time, the boy's amusement became the serious business of the father's life. What renders his success more remarkable is, that he, according to his own account, is totally unacquainted with mathematics. The signs of plus and minus are about the sum of his algebraical knowledge. How often does genius supersede what, to other men, would be an essential element to success! What sense is more essential to the student of natural history than that of sight; and yet Huber, one of the most successful and philosophic observers of modern times, was stone-blind! Mathematics, to the optician or astronomer, seem as essential as sight to the student of natural history; and, yet, some of the most popular writers on astronomy were totally destitute of the mathematical faculty. Ferguson
