CHINESE MIRRORS.
There is a puzzling property in many of the Chinese mirrors which deserves particular notice, and we may give it, together with the solution furnished by Sir David Brewster:—"The mirror has a knob in the centre of the back, by which it can be held, and on the rest of the back are stamped in relief certain circles with a kind of Grecian border. Its polished surface has that degree of convexity which gives an image of the face half its natural size; and its remarkable property is, that, when you reflect the rays of the sun from the polished surface, the image of the ornamental border and circles stamped upon the back, is seen distinctly reflected on the wall," or on a sheet of paper. The metal of which the mirror is made appears to be what is called Chinese silver, a composition of tin and copper, like the metal for the specula of reflecting telescopes. The metal is very sonorous. The mirror has a rim (at the back) of about 1-4th or 1-6th of an inch broad, and the inner part, upon which the figures are stamped, is considerably thinner.
"Like all other conjurors (says Sir David Brewster), the artist has contrived to make the observer deceive himself. The stamped figures on the back are used for this purpose. The spectrum in the luminous area is not an image of the figures on the back. The figures are a copy of the picture which the artist has drawn on the face of the mirror, and so concealed by polishing, that it is invisible in ordinary lights, and can be brought out only in the sun's rays. Let it be required, for example, to produce the dragon as exhibited by one of the Chinese mirrors. When the surface of the mirror is ready for polishing, the figure of the dragon may be delineated upon it in extremely shallow lines, or it may be eaten out by an acid much diluted, so as to remove the smallest possible portion of the metal. The surface must then be highly polished, not upon pitch, like glass and specula, because this would polish away the figure, but upon cloth, in the way that lenses are sometimes polished. In this way the sunk part of the shallow lines will be as highly polished as the rest, and the figure will only be visible in very strong lights, by reflecting the sun's rays from the metallic surface."
THE CADENHAM OAK.
Amongst the many remarkable trees in the New Forest in Hampshire, is one called the Cadenham Oak, which buds every year in the depth of winter. Gilpin says, "Having often heard of this oak, I took a ride to see it on the 29th of December, 1781. It was pointed out to me among several other oaks, surrounded by a little forest stream, winding round a knoll on which they stood. It is a tall straight plant, of no great age, and apparently vigorous, except that its top has been injured, from which several branches issue in the form of pollard shoots. It was entirely bare of leaves, as far as I could discern, when I saw it, and undistinguishable from the other oaks in its neighbourhood, except that its bark seemed rather smoother, occasioned, I apprehended, only by frequent climbing. Having had the account of its early budding confirmed on the spot, I engaged one Michael Lawrence, who kept the White Hart, a small alehouse in the neighbourhood, to send me some of the leaves to Vicar's Hill, as soon as they should appear. The man, who had not the least doubt about the matter, kept his word, and sent me several twigs on the morning of the 5th of January, 1782, a few hours after they had been gathered. The leaves were fairly expanded, and about an inch in length. From some of the buds two leaves had unsheathed themselves, but in general only one. One of its progeny, which grew in the gardens at Bulstrode, had its flower buds perfectly formed so early as the 21st of December, 1781.
"This early spring, however, of the Cadenham oak, is of very short duration. The buds, after unfolding themselves, make no further progress, but immediately shrink from the season and die. The tree continues torpid, like other deciduous trees, during the remainder of the winter, and vegetates again in the spring, at the usual season. I have seen it in full leaf in the middle of the summer, when it appeared, both in its form and foliage, exactly like other oaks."
Dean Wren, speaking of this tree, says, "King James could not be induced to believe the [Greek: to toi] (reason) of this, till Bishop Andrewes, in whose diocese the tree grew, caused one of his own chaplaines, a man of known integritye, to give a true information of itt, which he did; for upon the eve of the Nativitye he gathered about a hundred slips, with the leaves newly opened, which he stuck in claye in the bottom of long white boxes, and soe sent them post to the courte, where they deservedly raised not only admiration, but stopt the mouth of infidelitye and contradiction for ever. Of this I was both an eye-witness, and did distribute many of them to the great persons of both sexes in court and others, ecclesiastical persons. But in these last troublesome times a divelish fellow (of Herostratus humour) having hewen itt round at the roote, made his last stroke on his own legg, whereof he died, together with the old wondrous tree; which now sproutes up againe, and may renew his oakye age againe, iff some such envious chance doe not hinder or prevent itt; from which the example of the former villaine may perchance deterr the attempt. This I thought to testifie to all future times, and therefore subscribe with the same hand through which those little oakye slips past."
SCHOOL EXPENSES IN THE OLDEN TIME.