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To this edition, a large appendix is added, containing the relation of some farther experiments, in order to thew the dif. ferences between the heats imparted by pure and common air ; also a long series of experiments communicated by Mr. Gadolin, professor of chemistry at Abo, on the absolute heat of bodies, which confirm Dr. Irvine's opinion concerning the point of total privation; and a general view of the discoveries made by Dr. Black and Dr. Irvine. Here Dr. Crawford vindicates bimself against the insinuations which he says had been thrown out soon after the publication of the first edition of his work, ebat he had publithed Dr. Irvine's discoveries without aca knowleging the author; the copy of a letter from Dr. Irvine sufficiently proves the falsehood of the report. · At the end of the book, Dr. Crawford has given a general view of the results of all his experiments in the form of a table, exhibiting the comparative heats of different bodies to water, as the standard.

Ro....mo

Art. VI. An Account of some of the most remarkable Events of the

War between the Prusians, Aufrians, and Rufians, from 1756 to 1763: and a Treatise on several Branches of the Military Art, with Plans and Maps. Transated from the 2d Edition of the German Original of J. G. Tielke, by Capt. C. Craufurd, of the Queen's Regiment of Dragoon Guards, and Capt. R. Craufurd, of the 75th Regiment, late of the 101st. Volume II. large 8vo. 15 s. Boards. Walter. 1788. N a former number of our Review *, we announced the

first volume of this useful and elegant work. The articles in this second volume, as recited in the title-page, are divided into four sections. The first section contains derails of various marches of the troops of both armies, with divers skirmilbes, attacks of posts, and other movements of detachments and parties, previoully to the grand operations of the campaign. Although these are neither very important nor instructive, yet they are, in many places, rendered interesting by the valuable notes of the translators, explaining the nature and establishment of the Cofracks, and other irregulars in the Russian army; together with a description of some pieces of artillery peculiar to that service.

Section the second, gives a circumstantial account of the battle of Zorndorff, and a critical examination of the dispofitions of theywo, armies ; whence we learn, that the valour of the Ruffian foldiers was not employed to the greateft advantage, but that, on the contrary, they were so injudiciously formed,

• See Vol. Ixxviii. January 1788, p. 55.

as

as to be, in several parts, enfiladed by the Pruffian artillery, with such effedt, that one ball is said to have killed forty-two men. Many circumstances, both before and after this battle, do not seem to place the Russian general, Fermer, in a very advantageous point of view, either for vigilance or skill. The predilection of the Ruffians for the bollow square is here noticed, and justly censured.

Section the third, gives a minute journal of the fiege of Col. berg, for which neither the besieged nor the befiegers appear to have been properly furnished ; the garrison of that fortress confisting chiefly of militia and burghers, almost without engineers or artillery officers; the number of the besiegers was much too small for carrying on the necessary works ; and they were allo deltitute of a proper train of artillery, having only fix twelvepounders, and three or four guns of a lighter nature : they were likewise scantily provided with ammunition. The event was, the Ruflians were forced to raise the fiege, with the loss of between four and five hundred men; while that of the besieged is said, in their account, to have been only fix soldiers and two burghers. The defence of this place does great honour to the command. ant; and the like is due to the Rulian general for the strict discipline observed by his troops, with respect to the inhabitants of the environs of this place.

Section the fourth, contains the author's plan for taking the fortress by a coup de main; a variety of reafons (he fays) prevented him from laying it before the Russian generals, but that his knowlege of its state confirms him in the opinion that it might have been carried into execution in the latter end of 1758, or the beginning of 1759, but not later ; for, after that period, the whole was strengthened, and the garrison reinforced.

The different articles are illustrated by ten well engraved plans

We are extremely sorry to learn, from an advertisement at the conclusion of this volume, that the subscriptions have not been sufficient to defray the expences of the publication ; and that the Captains Craufurd do not think it advisable to proceed with the work, till they have firit ascertained whether there will be a fufficient number of subscribers; they, therefore, request that those who wish to subscribe, will fignify their intentions to Mr. Walter, the bookfeller; who is directed not to receive aný subscriptions, but only to make memorandums of the names.

and maps.

Gro.e.

Art.

dut. VIL. Ar Elay towards a Syftem of Mineralogy. By Axel Free deric Croostedt, Mine-Master, or Superintendant of the Mines in Sweden. Translated from the original Swedish, with Annotations; and an additional Treatise on the Blow-pipe, by Gustav voz Éngeltrom, Counsellor of the College of Mines in Sweden. The second Edition ; greatly enlarged and improved by the Addition of the modern Discoveries, and by a new Arrangement of the Articles. By John Hyacinth de Magellan, Talabrico-Lufitanos, Reg. Soc. Lond. Acad. Imp. Petro. &c. &c. Socius, 8vo. 2 Vois. 148. Boards. Dilly, 1785.

S moft of our mineralogical Readers are acquainted with A

Cronstedt's system, and as those who are not will find an epitome of it in our account of Engeftrom's translation, Rev. vol. xlii. p. 312, we shall now chiefly confine ourselves to a detail of the additions and valuable notes for which the public is indebted to Mr. Magellan.

The order adopted by the Author, in his fyftem, muft neces. sarily be somewhat altered in the present edition, to make it suitable to the improved state of the science. Mr, Magellan juftifies himself in this respect, by the authority of the great Bergman, who, speaking of this system, says, “ If the author had lived longer, for the benefit of the sciences, he would no doubt have retified the disposition of his mineralogical system.”

The clafles of minerals remain the same as in the original work, viz. ist Earths, 2d Salts, 31 Inflammables, and 4th Metals.

The firft class was divided into nine orders, one for each of the primitive earths; later discoveries and experiments, bow. ever, have now determined that all earths are reducible to these five, viz. Calcareous, Ponderous, Magnesian, Siliceous, and Argillaceous ; to which Mr. Magellan has referred all the genera of Cronstedt. Among the additions to this class, are some just observations on marle, and arable soil, and on the several compounds of calcareous earth. Ponderous earth, or barytes, was unnoticed in the former edition, as was also magnesia. Under this last mentioned earth, Mr. Magellan has placed Epsom salt, p. 97 ; and under the order of neutral salts, we observe vitriolated magnesia, p. 384 ; thus placing the same substance in two different classes. Similar duplicates allo occur; but they refer to each other,—as muriatic chalk among the salts, p. 380, and muriatic calcareous earth among the earths, 2. 39-Is Vitriolum Vineris among the metals, p. 695, and among the salts, p. 401; with some others. This circumstance, however, could not be avoided, and is of no consequence where the reference is made; it is agreeable to the general system, which classes bodies accord ing to their component parts.

To

To enumerate all the additions which Mr. Magellan has made, would increase our article too much. His notes are the most valuable, being partly compiled from our best authors, and partly original ; of these last, those on diamonds and precious ftones contain much real information. The note on clay gives an abridged account of Mr. Wedgwood's thermometer, with a comparative view of his and Fahrenheit's scale.

Among the salts, many additional sections are introduced, one of which is allotted to the aerial acid. This is not the only air that is claffed in the mineral kingdom; inflammable and bepatic airs have places allotted to them in the 3d class, in the notes to which Mr. Magellan gives a concise view of the phlogiftian and antiphlogistian doctrines. The plumbago, compounded of phlogiston and aerial acid, is separated from the molybdena, and classed among the inflammables, while molybdena is retained among the semi-metals.

The notes to the fourth class are more numerous than those which Mr. Magellan bas given with the other three. The utility of metals in common life, and the variety of forms under which they appear, afford much room for enlarging on the subject. Gold, as in most systems, holds the first rank. The editor, like other writers on the subject, gives several instances of its duetility. We should not have mentioned this circumstance but for the fake of correcting some typographical errors in the note at page 513, in the last paragraph of which 3-3 square inches ought to be 3.3 inches Square; 272.23 ought to be 272.25; and 56.718, 56.7975. These however are small defects, and are amply counterbalanced by the great fund of chemical and metallurgical knowlege which the notes contain.

Quicksilver is brought from the place in which it was formerly arranged, and numbered with the perfect metals. Mr. Magellan concludes his long but valuable notes on this metal, with the following paragraph the fubject on which he expatiates being the different specific gravity of different parcels of quicksilver :

• Before I dismiss the subject, I must beg leave to give a specimen or two of the enormous blunders committed by various philoSophers and numerous pretenders, who have been extremely busy in our times, to determine the heights of mountains, and the relative position of places above the level of the sea, by means of barometri. cal observations, without paying any particular attention to the specific gravity of the mercury, with which their barometers were made. If the two barometers were both at 30 inches high, and equally circumstanced in every other respect, excepting only the specific gravity of their quicksilver ; so that one be filled with the first kind I have tried, viz. whose specific gravity was = 13.62, and the other = 13.45; in this case, and in all probability many of this kind have often occurred, the error must have been no less than 327 feet; because the heights of the mercurial columns in each baro

meter

meter muß be in the inverse ratio of their specific gravities, viz.
13.45: 13.62 :: 30:30:379.

Now the Logarithm of 30 = 4771.21
And

of 30.379 = 4825.73
The difference

54.52 fathoms, which difference shews that there are 54.52 fathoms between one place and another, or 327 * feet; though in reality both places are on the same level.'

This is a just remark, and ought to be observed by instrument-makers when they conftruct barometers for measuirng heights. The specific gravity of the mercury may be marked on some part of the instrument, and will be useful for other purposes beside measuring heights.

The notes to the baser metals contain, like the rest, a variety of useful observations relative to smelting, preparing, purifying, and combining the metals for various purposes : describing the uses to which they may be conveniently applied, and the danger attending them when not properly manufactured. Beside these practical observations, Mr. Magellan introduces no small thare of philosophy; the subject indeed requires it: and though his notes do not abound with what was before altogether unknown, yet by collecting, from various authors, the Tater discoveries and improvements, and bringing them together in a regular manner, he hath rendered science a material service. Where he has discovered errors, he hath corrected them; and where the opinions of former writers have been apparently oppofite or contradictory to each other, he has, by philosophical investigation, pointed out the cause of these disagreements, and reconciled them.

By way of Appendix, he has added a description of two portable laboratories for aslaying minerals, and making chemical experiments on a small scale. The apparatus is ingeniously contrived, and seems weil calculated for making the intended trials.

A second Appendix contains several particulars useful to mineralogical enquirers, especially the method of analysing earths and ftones, as given by Mr. Kirwan ;-the description of an inftrument for finding specific gravities, by the very in genious Mr. Nicholson ; and an easy method of procuring accurate original weights.

The Efsay on the Blow-pipe, by Mr. Engeltrom, is also added, and enriched with many notes, on the relulis of experiments made with that inftrument, and the proper mode of uling it,

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* These are all French measure. Rev. Jan. 1789.

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