(45, 46). Item, two cylinders, with their wooden boxes,—the one of steel, which is most usual in England; the other of foyled isinglass, which I met with often in High Germany, from whence I brought this. The isinglass having a foyle of quicksilver and pewter put behind it, like a lookingglass, will afterward easily bend to the cylindrical piece of wood that you would fasten it to, and rendereth an excellent lustre, better than the steel. There are several uses of them in opticks. I used them with some several pictures, which are artificially painted like the greatest confusion of irregular lines and lineaments that may be. But, a cylinder being placed upon the square fitted for its pedestal, all the reflections of that seemingly confused work meet in the cylinder, and make a well-shaped, very handsome picture, in its due points and proportions. As to one of these cylinders belongeth, from the confusion on the plain, in the cylinder, an emperor on horseback on a white horse (which I brought from Rome, but they may be had in England).

The other, that I out of curiosity used to imploy, was in a very pretty experiment that I learned at Nurimberg and Augsberg, in High Germany, in making, by reflection of the sun’s beam, as fair a rainbow as ever was seen in the sky, to be seen in a dark room—the darker the better—which I have done hundreth of times before many of quality, who have taken delight to see it. It is best done where there are close wooden shuts to the windows. It is done thus: the room being made very dark, there must be left only an auger hole, where the sunbeam may come clearly in through the shut,—the kesment being taken away, or a pannel of glass broken for the purpose, that the sun may be clear. Then lay to that hole a common prism or triangular artificial crystal, that casteth all kind of colours; the sun, without it, casteth through the hole a round spot of light, either upon the next wall, or on the floor; then that triangular crystal, being put to the hole, turneth that sunbeam into a round spot of divers glorious colours; then put a couple of small nails for the prism to rest upon, and keep that glorious spot; which done, take a cylinder, and hold it about a foot distance from the coloured spot, full in the sunbeam, or at what distance you find most convenient, and that will cast the reflections of that spot all round about the dark room, on the seeling and walls, in as perfectly various colours as ever you saw the rainbow. Upon which there happened a pretty passage to me once, which happened at Utrecht, which was this: there lived one Myn Here Johnson,[*] Cornelius Jansen “in 1636 and the next following years resided with Sir Arnold Braems, a Flemish merchant at Bridge [Place], near Canterbury.” (Dallaway’s note in Walpole’s Anecdotes of Painting in England, ii. 10, Lond. 1828.) His portrait of Dean Bargrave is in the Deanery at Canterbury, and was lent for the National Portrait Exhibition of 1866. an extraordinary eminent painter, of my former acquaintance in England. I showed him this artificial rainbow; he asked me how long I could keep it; I told him that I could keep it 2 or 3 hours: “Then," saith he, “I will send for my pallat of coulors, and draw it, for I have binn after endeavouring to draw one in the fields, but it vanished before I could finish it.” Upon which I laughed. He asked me why I laughed; I told him that he should see anon why I laughed, but assured him that I could keep the rainbow 2 or 3 hours; upon which he sent a servant for his pallat of coulors, and, being come, he tempered them to his purpose in the light. Then I darkened the room, but he could not see to paint, at which I laughed again, and I told him his error, which was, that he could not see to paint in the dark, and that I could not keep the rainbow in the light, at which he laughed also heartily, and he missed his design.

Item, a picture in a frame, of confused work; but a cylinder being placed on the square for its pedestal, there you shall see an emperor on horseback, and, if you moove your head up and down, the horse will seem to trott.