Possibly, however, this may be the sketch for a design on the ceiling of a room which he did when he was sixteen. It included “two figures, representing Astronomy and Geometry and their Attributes, artfully drawn with his pen.” I cannot affirm that the lady in the heirloom copy is a piece of his “artful” drawing, but it is likely. What seems to fix the start of Wren’s studies with Scarborough as roughly contemporary with his _Panorganum_ letter is the fact that the boy in 1647 was engaged in translating into Latin, at Sir Charles’ request, Oughtred’s _Clavis Mathematicæ_. In the same year he had a patent granted him for a diplographic instrument for writing with two pens. Christopher describes his invention at length. An instrument of the kind must have then seemed very important, because Sir William Petty patented a similar contrivance in the same year. About three years later someone stole Wren’s invention. He was exceedingly annoyed, and wrote a letter in which he refers to the fact that Oliver Cromwell’s attention had been directed to it. Without claiming anything great for the invention itself, he wanted to clear himself from the aspersion of having annexed somebody else’s device. In later years there were to be many examples of people picking up an idea of Wren’s, developing it to their own great credit, and failing to acknowledge the man without whose idea they never would have started on their enterprise. Whenever it was that Wren began working under Sir Charles Scarborough, it was not until his fifteenth year that he informed his father that he was acting as a demonstrating assistant to the physician who lectured on anatomy at Surgeons’ Hall. The story of his activities is set out in a dignified Latin letter, which refers not only to the Scarborough activities, but to Wren’s invention of a weather-clock, of an instrument to write with in the dark, and of a treatise on spherical trigonometry. Very impressive also is a long metrical Latin essay on the Reformation of the Zodiac, which runs to nearly fifteen quarto pages, in an appendix to Elmes’ _Life_. He was sixteen when he wrote (again in Latin) to Mr. Oughtred, whose important essay on geometry he had translated into Latin. We may agree with Elmes that “these juvenile essays prove the fecundity, the ripeness, and the highly cultivated state of his mind, his zeal, and his ardent enthusiasm in the pursuit of knowledge and literary honours.” But the weather-clock was destined to develop from the stage of a “juvenile essay.” When he wrote to his father in 1647 that he was enjoying Scarborough’s society, he added that he had imparted to him “one of these inventions of mine, a weather-clock--namely, with revolving cylinder, by means of which a record can be kept through the night.”