could never understand the logical process by which the forty-seventh proposition of the first book of Euclid is proved; yet he perfectly understood the property of the right-angled triangle. He convinced himself of its truth by cutting the squares out on pasteboard, and weighing the largest one against the other two. The late Dr Dick, who did so much to diffuse a knowledge of the facts cf astronomy, never could master the logic of the pons asinorum, though he quite understood the nature of the property demonstrated. Mr Clarke is also a good example of his order in another respect. He is a hearty, hilarious man, like all amateur workers in lenses and specula, who are always overjoyed when they meet a brother who can enter into their tastes, and listen patiently to the detail of all their failures and successes. There is, certainly, something in the occupation that is calculated to bring out all that is genial and benevolent in a man's character. It was very satisfactory to hear Mr Clarke describe, in glowing terms, a late visit to England, when he made the acquaintance and enjoyed the hospitality of our English astronomers. The gratification, we doubt not, was mutual; and no English astronomer will pay a visit to the Cambridge optician without carrying away with him pleasant reminiscences of his home and his workshop.
Though America is now taking a lead in the manufacture of the optical part of telescopes, American astronomers freely admit that they are far behind in
