Nobel Enventions.

Improved Gun-lock-stop.

MR. WESTLY RICHARDS, of Birmingham, has invented a very simple and safe bolt, for the purpose of preventing a gun from being discharged accidentally. It consists of a small sliding piece or bolt attached to a scroll at the back part of the guard, which piece locks into a notch in the hinder part of the trigger, and prevents the trigger from being drawn back, consequently confining the sear and other internal parts of the lock, and thereby precluding the possibility of the piece being discharged until the bolt is withdrawn, which is only to be done by the little finger or side of the right hand, when the piece is presented from the shoulder.

This contrivance is shewn in Plate IV. at fig. 10. The construction of the gun lock is the same as others upon the percussion principle; a is the scroll behind the guard, which, instead of being a continuation of the guard, as usual, is made in a distinct piece, and attached to the gun by two small buttons that pass through mortice holes in the guard plate; b is the bolt, extending from and forming part of the scroll piece; c is the hinder part of the trigger, which has the notch that the bolt, b, passes into. The piece being cocked and brought to the shoulder to be discharged, the little finger of the right-hand pushes the scroll back and unlocks the trigger, when the piece may be let off as usual.

Polytechnic and Scientific Entelligence.

ROYAL SOCIETY.

THE sittings of the Royal Society were resumed for the season on Thursday, the 17th of November, at which meeting a paper was communicated by Dr. Davy, entitled, Observations on the Changes which have taken place in some ancient alloys of Copper.

The author first describes the nature of an incrustation' upon an ancient helmet, found in a shallow part of the sea between the citadel of Corfu and the village of Castrades; the surface was of a variegated colour, mottled with spots of green, dirty white, and red: the red and green patches exhibited minute crystals of red oxide of copper and metallic copper, and were further composed of its green submuriate and carbonate; the dirty white parts consisted chiefly of oxide of tin.

These new combinations are only superficially produced: the metal was found bright beneath, and consisted of copper alloyed with 18.5 per cent. of tin.

An ancient nail from a tomb in Ithaca, and a mirror from a tomb at Samos, in Cephalonia, afforded nearly similar, but less distinctly, crystalline results. The copper in the mirror was alloyed with 6 per cent. of tin, and a minute portion of arsenic.

The examination of the incrustation upon ancient

coins, consisted of oxide of tin, and of carbonate, and submuriate of copper; it, in some cases, acquires a dingy hue, from the prevalence of black oxide of copper, mixed with a little of its protoxide.

The author could discover no connexion between the perfect state of preservation of ancient coins, and their composition; but he observes, that the manner in which the crystalline structure of the incrustation is acquired, is a peculiarly interesting question. There being no reason to suspect deposition from solution, "are we not," says the author, "under the necessity of inferring, that the mineralizing process witnessed in its effects depends on a slow motion and separation of the particles of the original compound; and must we not conclude that this motion is connected with the operation of attractions of different kinds, as chemical affinity, electro-chemical attraction, and attraction of aggregation?" If this conclusion be just, the author remarks, that it opens a new field of inquiry, which may help to explain several phenomena in mineralogy and geology,

At the same meeting a paper was also read, entitled, Observations of the Apparent Distance and Positions of 460 double and triple Stars, made in the years 1823, 1824, 1825, together with a re-examination of 36 Stars of the same description, the distances and positions of which were communicated in a former Memoir, by James South, F.R.S.

The author prefaces these observations with a brief account of the instruments with which, and the circumstances under which, they were made. The former being the same with which the observations previously communicated to this society were made, and being fully described in the former paper alluded to in the title of this, require no further particular description; he contents

himself therefore with noticing, that by a different adap. tation of their parts, higher magnifying powers than those formerly employed were obtained, and a series of powers from 92 to 787 used in a part of the observations. A large portion of these observations were made at Passy, near Paris; and the author takes occasion to make honourable mention of the facilities afforded him on the part of the French government, for the ingress and regress of his instruments into and out of France, and of the attention and assistance uniformly afforded him while resident there by many distinguished individuals.

Of the stars whose measures are here presented, he states that about 160 are hitherto undescribed, and probably new. The places of these are given merely with sufficient exactness to enable any one to find them in future. The remainder are in great measure stars comprised in M. Struve's catalogue of 796 double and triple stars, and among these about 160 belong to those examined for the first time by Sir Wm. Herschel.

The observations themselves are stated in a manner somewhat different from that adhered to in the former communication already alluded to. Instead of giving all the individual micrometrical measurements on which they depend, (about 14,000 in number,) which would have swelled the paper to an enormous bulk, only the mean results of each set of measures are given; but to afford every opportunity of forming an impartial judgment of their validity, not only the number of measures on which it depends is annexed to each mean result as stated, but also the difference between the greatest and least measure taken, or the limits within which all the measures necessarily lie.

The stars themselves are arranged in order of right as

cension for convenience of reference. After the statement of the mean results of the several sets of observations both of angle and distance, a final mean, with a mean date for an epoch, is deduced. In the case of Sir Wm. Herschel's stars, a comparison of the measures now obtained with those given in his catalogues, or now for the first time brought to light by a careful examination of his manuscripts, is subjoined. By this comparison several fresh instances have been found of double stars, in which the relative motion of the individuals composing them is satisfactorily proved. In one remarkable case, (that of star♪ Equulei,) this change has gone to an enormous extent, and is satisfactorily referred to proper motion in the large star. In another, not less singular, all the three stars of a triple star ( Cancri) are ascertained to be relatively in motion, describing orbits about each other, and forming probably a ternary system connected by the mutual gravitation of its members; thus completely justifying the views taken by Sir Wm. Herschel of this subject in his papers published in the transactions of this society in 1802 and 1804.

Annexed, as an appendix to these observations, is a reexamination of about 36 stars, measured in the former paper already alluded to, and which were considered as presenting peculiar interest from the evidence then obtained of their relative motion, and of their connection in binary systems. The results of this re-examination are in the highest degree satisfactory, as, with only two or three exceptions, these stars have been found to continue their motions in the directions, and in the greater number of cases, with nearly the velocities predicted. In the most remarkable case, that of the double star Ursæ majoris, an angle of nearly 14° has thus been described by the two