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Lamp without Flame.—A very curious lamp has recently been constructed in London, upon the principle of Sir Humphry Davy's late discoveries, which, while it forms a very amusing philosophical experiment, promises to be of considerable use. A cylindrical coil of platina wire, about 1-100th of an inch thick, and containing about ten turns, is placed, part of it round the cotton wick of a spirit lamp, and part of it above the wick: The lamp is then lighted so as to heat the wire to redness. When the flame is blown out, the vapour of the alcohol will keep the upper part of the wire red hot, as long as there is a supply of alcohol, of which the expenditure is very trifling. The heat of the wire is sufficient to kindle German fungus, or paper prepared with nitre; so that a sulphur match may be lighted when it is required. A wick composed of twelve threads of the ordinary sized lamp cotton yarn, will require about half an ounce of alcohol to keep it lighted for eight hours. When the wire becomes oxided, it is necessary to uncoil it, and rub it bright again with fine glass paper.

Captain Kater has found, that the length of the pendulum vibrating seconds, in vacuo, at the level of the sea, is 39.1386 inches of Sir George Shuckburgh's scale, the scale being at 32°, and the latitude of the place of observation, 51° 31' 8" .3. In an appendix to Captain Kater's paper on the pendulum, Dr Thomas Young has given a new and elegant demonstration of a theorem discovered by Laplace, that if a compound pendulum be made to vibrate on cylinders instead of knife edges, the distance between the surfaces of the cylinders will be the equivalent pendulum.

Sir Humphry Davy has repeated the experiments on muriatic acid gas, which have lately been made by Dr Andrew Ure of Glasgow, and Dr Murray of Edinburgh, and has found, that the water which these chemists obtained was merely an accidental product. He found that the oxide of lead, and the alkali in the flint glass, both furnished the oxygen.

Dr E. D. Clarke and Mr Holmes of Cambridge, have analyzed a new mineral from Sweden, to which they have given the name of Berzelite, in honour of the illustrious chemist, Baron Berzelius of Stockholm. It consists of

Its specific gravity is 2.45, nearly equal to that of quartz. It scratches glass, and has a general resemblance to white quartz. It admits of a twofold cleavage, parallel to the sides of a rhomboidal prism, two of which, parallel to each other, are splendent, and the other two are dull.

A method of making doubly refracting prisms, perfectly achromatic, has been invented by Dr Brewster; a full description of the method will be found in the Annals of Philosophy for March 1818.

Our celebrated countryman, Dr Gregory, Professor of the Practice of Physic in the University of Edinburgh, has been elected a corresponding Member of the Institute of France, in the Class of Medicine;—the candidates were, Dr Matthew Baillie, M. Lauth of Strasburg, M. Maunoir of Geneva, and M. Fodere of Strasburg.

Remarkable Acoustic Experiment.—M. Pictet, of Geneva, states a curious circumstance relative to sound, on occasion of a visit which he lately paid to a manufactory of sulphuric acid at Winterthur in Switzerland. The rooms in this manufactory are very large. One of them was empty, says M. Pictet, and the proprietor, M. Ziegler, invited us to avail ourselves of this occasion for making a very curious experiment. It was this: When you introduce your head into this room, by a lateral window, about breast-high, and sound the notes ut mi sol, they produce a perfect chord in one continuous sound, like that of stringed instruments. This chord is kept up for about ten seconds in a manner highly pleasing to the ear, which can even distinguish octaves above those which have been sounded.—M. Pictet ascribes this effect to the reciprocal and perfectly regular reflections of all the faces of the parallelepipedon in which these reflections are formed by vibrations of air respectively isochronal to those which belong to the notes sounded; but which being prolonged all at once for a longer or shorter time, produce the continuous accord which is heard.

The Titi Ape.—According to the description of M. Von Humboldt, the species of ape called Titi, seems to approach nearer to man in a variety of points than any other of its genus. Its features exactly resemble those of a child; they have the same expression of innocence, the same roguish smile, and the same sudden transitions from joy to grief. The Indians assert, that the Titi weeps, in like manner, when it is vexed; and this statement is perfectly accurate. Whenever it is frightened or crossed, its eyes fill with tears. The Titi is in constant action; but its motions are as graceful as they are rapid: you never find it angry or ill-tempered, but always playing, skipping about, or catching insects, among which it