Oldalképek
PDF
ePub

only of the profession in this country. To remedy this inconvenience, application has been made to Mr. JOHN AUGUSTINE SMITH, of the Royal College of Surgeons in London, and Professor of Anatomy and Surgery in the College of Physicians and Surgeons of New-York, to publish an abridged edition of the "Principles of Surgery." But to reduce Mr. Bell's book to any moderate size, to correct where correction might be deemed necessary, to compare him with other authors, and to state the result, would be so to change the work that it could no longer be called BELL'S SURGERY. Moreover, it is certainly improper to publish mutilated copies of a work, particularly during the life of the author. Such an opinion is entertained of the merit of Mr. Bell's performance, that if a cheap edition of it could have been printed here, it would not have been necessary to undertake a new system of Surgery. The work is intended to be so nearly an abridgment of Mr. Bell's, as to supersede the necessity of such a publication, and, at the same time, so much an original performance as to admit of the introduction of any important matter from other sources. will be published by Messrs. Collins and Perkins.

It

They have likewise in the press the Anatomy of the Human Body, by JOHN and CHARLES BELL, in two large octavo volumes, from the third London edition corrected, and illustrated by one hundred and twenty-five engravings.

The publication in this country of medical works, at all times a matter of the greatest consequence to the profession, is now peculiarly so, when the importation of foreign books is entirely suspended. The cheapness of American editions, for they are sold at half, or less than half the price charged for those printed in London, is a consideration of great importance, particularly to those who purchase to a considerable amount. It has been objected to the editions issued from our presses, particularly those in which there are plates, that though cheaper, they are likewise inferior to those imported. This we think will not be the case with the above edition of Bell's Anatomy, for we

have seen some of the plates which are superior to those in the London copy. The extensive sale of the book will, we hope, remunerate the activity and enterprise of the publishers.

Quincy's Lexicon improved.

Messrs. T. & J. SWORDS, the proprietors of the improved American edition of Quincy's Lexicon, are preparing for the press a new edition of this valuable medical dictionary, which it is expected will make its appearance in the course of the ensuing summer.

FOREIGN.

Account of farther Discoveries in extracting Metals from the

Earths and Alkalies.

The Swedish chemists, M. PONTIN and BERZELIUS, have succeeded in obtaining amalgams of the metals of lime and barytes, of magnesia and of strontites, by exposing these earths moistened to negatively electrified mercury; but this method has no effect on alumen or silex. These gentlemen have also made a very interesting experiment on ammonia; they placed a solution of it in contact with mercury, negatively electrified, as in the former experiments, and thus succeeded in obtaining a soft amalgam, which proves its metallic nature.

Mr. DAVY has since improved on the discovery of the Swedish chemists. The amalgam of barytes and mercury obtained by their method was distilled, and the mercury being driven off, he obtained the metal of barytes in a pure form: and by the same process he procured the metals of strontites and magnesia nearly pure. The earths are mixed with red precipitate, which is negatively electrified; the amalgam is absorbed by fresh mercury, and when it becomes semi-fluid, is distilled in the vapour of naphtha in a tube of plate glass.

The above facts were communicated by Mr. DAVY to the Royal Society a few weeks ago, when he also stated, that in experiments made with a voltaic battery of 36,000 square inches, on barytes, strontites, and the other alkaline earths, and on silex and alumen; all these bodies, when slightly moistened, and acted on by iron wires negatively electrified, undergo changes at the points of contact; and the metals of the earths appear to form alloys with the negatively electrified iron.

Mr. DAVY likewise metallized the earths by electrifying them when mixed with the oxyds of lead, of silver, or of mercury, when the metals of the earths and the common metals were revived together in the state of alloy.

Since Mr. DAVY's first discovery of the metallic nature of the alkalies by the voltaic battery in last November, several others have been made relative to them and the earths, with a rapidity seldom witnessed before on similar occasions. Soon afterwards the discovery of the French chemists was made, that the metal of potash might be obtained in large quantities without the aid of galvanism, by means of the superior attractions of iron and charcoal for oxygen in a strong heat, and the tendency of the new metal to form an alloy with iron; and in the foregoing short notice are contained no less than four more important discoveries; that of the Swedish chemists, of the effect of negatively electrified mercury in accelerating the metallization of the earths; and those of Mr. Davy, of the ob taining these metals púre, by the distillation of the amalgams so formed; of the operation of the oxyds of lead, silver, and mercury, when electrified, in reviving the metals of the earths by forming alloys with them, and of the same effect produced by negatively electrified iron in the metallic state.

The discovery of ammonia being of a metallic nature, shows that it is probable the very air we breathe contains metal in a gaseous state; for azote, which forms a large portion of our atmosphere, has long since been proved to be a component part of ammonia.

[blocks in formation]

Silex and alumen having both proved refractory to the processes which obtained metals from the other earths, gives additional weight to the old opinions of their being of the same nature, or of their being different modifications of the same substance. [Athenæum, Sept. 1808.

Davy and Singer's Chemical Experiments.

It has been asserted by most writers and experimentalists, that silver burns with a bright emerald-green light. In Mr. DAVY's late lectures at the Royal Institution, the deflagration of silver leaf was attended by the emission of a brilliant white light, which the professor ascribed to the great purity of the silver employed; and he expressed an opinion that the green flame usually observed, arose from the admixture of copper with the silver. Mr. G. B. SINGER has, however, discovered that this phenomenon proceeds from a different cause. Having observed that Mr. Davy's conducting wires were terminated by charcoal, he repeated the experiment with a similar arrangement; and applying the charcoal to a pure silver leaf, it immediately burned with a beautiful white light. Some of the same portion of silver having been before employed when the green flame was produced, it became evident that the white light in this and in Mr. Davy's experiment proceeded from the char"coal; and that this was really the case, appeared from the im`mediate evolution of green light, when the contact was made by a metallic wire. By the application of charcoal to the extremity of a wire, so bent that either the wire or the charcoal may touch the silver at pleasure, the white and the green flame 'may be alternately produced; and a conclusive demonstration of the fact, with a pleasing variation of a brilliant experiment, will be thus at once afforded.

Reade and Hincks's 'Chemical Experiments.

Dr. JOSEPH READE has published an account of an experiment, the result of which is in direct contradiction to the re

ceived opinion, that the agitation or friction of fluids cannot excite sensible heat. It is as follows:-The temperature of the apartment being 40°, half a pint of water at a similar heat, was poured into a tin, bottle-shaped vessel, into the aperture of which was inserted a thermometer surrounded with chamois leather, and made to fit accurately, with its bulb nearly in the axis. After briskly agitating the vessel for a few minutes, to his great surprise, he found that the temperature of the water rose eight degrees; and, even after the apparatus was unco vered and laid at rest on the table, the water continued to rise for several minutes; proving the origin of the heat to be inhe rent in the fluid, and independent of any external causes, Anxious to obviate every source of fallacy or objection, Dr. Reade prevented the communication of caloric by his hands, or of radiation from his body by coating the tin vessel with many layers of woollen cloth carefully wrapped round it, over which there was a tin case, the entire nearly two inches in thickness, and covered externally with three wet towels. In the course of the experiment he dipped his hands frequently in snow water, and also sprinkled the towels. The Rev. Mr. Hincks, lecturer on chemistry in the Cork Institution, to whom the experiment was communicated, on repeating it in a glass bottle, found the heat of the vessel, by means of a thermometer placed between it and the covering, to be inferior to that of the enclosed fluid, and on a par with the atmosphere, which proves, in a most satisfactory manner, that there could be no communication of caloric from the hand.

Chemical Effects of Galvanic Electricity.

Some of the extraordinary effects of electricity in producing chemical decomposition, and in changing the ordinary affinities of different substances for one another, mentioned in Mr. DAVY's first Bakerian Lecture of 1806, are the following:

When compounds soluble in water were put into water contained in agate cups, and electrified, the decomposition was

« ElőzőTovább »