To this edition, a large appendix is added, containing the relation of some farther experiments, in order to fhew the differences between the heats imparted by pure and common air; alfo a long feries of experiments communicated by Mr. Gadolin, profeffor of chemistry at Abo, on the abfolute heat of bodies, which confirm Dr. Irvine's opinion concerning the point of total privation; and a general view of the difcoveries made by Dr. Black and Dr. Irvine. Here Dr. Crawford vindicates himself against the infinuations which he fays had been thrown out foon after the publication of the first edition of his work, that he had published Dr. Irvine's difcoveries without acknowleging the author; the copy of a letter from Dr. Irvine fufficiently proves the falfehood 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. R.....m.

ART. VI. An Account of fome of the most remarkable Events of the War between the Pruffians, Auftrians, and Ruffians, from 1756 to 1763 and a Treatife on feveral Branches of the Military Art, with Plans and Maps. Tranflated 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 101ft. Volume II. large 8vo. 15s. Boards. Walter. 1788.

Na former number of our Review *, we announced the firft volume of this useful and elegant work. The articles in this fecond volume, as recited in the title-page, are divided into four fections. The firft fection contains details of various marches of the troops of both armies, with divers fkirmishes, attacks of pofts, and other movements of detachments and parties, previously to the grand operations of the campaign. Although there are neither very important nor inftructive, yet they are, in many places, rendered interefting by the valuable. notes of the tranflators, explaining the nature and establishment of the Coffacks, and other irregulars in the Ruffian army; together with a defcription of fome pieces of artillery peculiar to that fervice.

Section the fecond, gives a circumftantial account of the battle of Zorndorff, and a critical examination of the difpofitions of the two, 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 fo injudiciously formed,

*See Vol. lxxviii. January 1788, p. 55..

as to be, in feveral parts, enfiladed by the Pruffian artillery, with fuch effect, that one ball is faid to have killed forty-two men. Many circumftances, both before and after this battle, do not feem to place the Ruffian general, Fermer, in a very advantageous point of view, either for vigilance or fkill.The predilection of the Ruffians for the hollow fquare is here noticed, and juftly cenfured.

Section the third, gives a minute journal of the fiege of Colberg, for which neither the besieged nor the befiegers appear to have been properly furnished; the garrifon of that fortrefs confifting chiefly of militia and burghers, almoft without engineers or artillery officers; the number of the befiegers was much too fmall for carrying on the neceffary works; and they were also deftitute of a proper train of artillery, having only fix twelvepounders, and three or four guns of a lighter nature: they were likewife fcantily provided with ammunition. The event was, the Ruffians were forced to raise the fiege, with the lofs of between four and five hundred men; while that of the befieged is faid, in their account, to have been only fix foldiers and two burghers. The defence of this place does great honour to the commandant; and the like is due to the Ruffian general for the strict difcipline 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 Ruffian generals, but that his knowlege of its ftate 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 ftrengthened, and the garrifon reinforced.

The different articles are illuftrated by ten well engraved plans and maps.

We are extremely forry to learn, from an advertisement at the conclufion of this volume, that the fubfcriptions have not been fufficient 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 firft afcertained whether there will be a fufficient number of fubfcribers; they, therefore, requeft that those who wish to fubfcribe, will fignify their intentions to Mr. Walter, the book feller; who is directed not to receive any fubfcriptions, but only to make memorandums of the

namès.

Gro.e.

ART.

ART. VII. An Effay towards a Syftem of Mineralogy. By Axel Fre deric Cronstedt, Mine-Mafter, or Superintendant of the Mines in Sweden. Tranflated from the original Swedish, with Annotations; and an additional Treatife on the Blow-pipe, by Gustav von Engeftrom, Counsellor of the College of Mines in Sweden. The fecond Edition; greatly enlarged and improved by the Addition of the modern Difcoveries, and by a new Arrangement of the Articles. By John Hyacinth de Magellan, Talabrico-Lufitanus, Reg. Soc. Lond. Acad. Imp. Petro. &c. &c. Socius. 8vo. z Vois. 14s. Boards. Dilly. 1788.

moft of our mineralogical Readers are acquainted with

A Croftedt's fyftem, and as thofe who are not will find an

epitome of it in our account of Engeftrom's tranflation, 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 neceffarily be fomewhat altered in the prefent edition, to make it fuitable to the improved ftate of the fcience. Mr, Magellan juftifies himself in this refpect, by the authority of the great Bergman, who, fpeaking of this fyftem, fays, "If the author had lived longer, for the benefit of the fciences, he would no doubt have rectified the difpofition of his mineralogical fyftem." The claffes of minerals remain the fame as in the original work, viz. ft Earths, 2d Salts, 3d Inflammables, and 4th Metals.

The first class was divided into nine orders, one for each of the primitive earths; later difcoveries and experiments, however, have now determined that all earths are reducible to these five, viz. Calcareous, Ponderous, Magnefian, Siliceous, and Argillaceous; to which Mr. Magellan has referred all the genera of Cronstedt. Among the additions to this clafs, are some juft obfervations on marle, and arable foil, and on the feveral compounds of calcareous earth. Ponderous earth, or barytes, was unnoticed in the former edition, as was alfo magnefia. Under this laft mentioned earth, Mr. Magellan has placed Epfom falt, P. 97; and under the order of neutral falts, we obferve vitriolated magnefia, p. 384; thus placing the fame fubftance in two different claffes. Similar duplicates alfo occur; but they refer to each other, as muriatic chalk among the falts, p. 380, and muriatic calcareous earth among the earths, p. 39-as Vitriolum Veneris among the metals, p. 695, and among the falts, p. 401; with fome others. This circumftance, however, could not be avoided, and is of no confequence where the reference is made; it is agreeable to the general fyftem, which claffes bodies according 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 beft authors, and partly original; of these laft, thofe 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 fcale.

Among the falts, many additional fections 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 hepatic airs have places allotted to them in the 3d class, in the notes to which Mr. Magellan gives a concife view of the phlogiftian and antiphlogiftian doctrines. The plumbago, compounded of phlogifton and aerial acid, is feparated from the molybdena, and claffed among the inflammables, while molybdena is retained among the femi-metals.

The notes to the fourth clafs are more numerous than those which Mr. Magellan has 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 moft fyftems, holds the firft rank. The editor, like other writers on the fubject, gives feveral inftances of its ductility. We should not have mentioned this circumftance but for the fake of correcting fome typographical errors in the note at page 513, in the last paragraph of which 3.3 Square inches ought to be 3.3 inches fquare; 272.23 ought to be 272.25; and 56.718, 56.7175. These however are fmall defects, and are amply counterbalanced by the great fund of chemical and metallurgical knowlege which the notes contain.

Quickfilver 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 quickfilver :

• Before I dismiss the fubject, I must beg leave to give a specimen or two of the enormous blunders committed by various philofophers and numerous pretenders, who have been extremely busy in our times, to determine the heights of mountains, and the relative pofition of places above the level of the fea, by means of barometrical obfervations, 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 refpect, excepting only the fpecific gravity of their quickfilver; fo that one be filled with the first kind I have tried, viz. whofe fpecific gravity was 13.62, and the other 13.45; in this cafe, 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 must be in the inverfe ratio of their specific gravities, viz. 13.45: 13.62:30: 30.379. Now the Logarithm of 30

And

of 30.379

4771.21

4825.73

54.52 fathoms,

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

This is a juft remark, and ought to be obferved by inftrument-makers when they conftruct barometers for meafuirng heights. The specific gravity of the mercury may be marked on fome part of the inftrument, and will be useful for other purposes befide measuring heights,

The notes to the bafer metals contain, like the reft, a variety of useful obfervations relative to fmelting, preparing, purifying, and combining the metals for various purposes: defcribing the uses to which they may be conveniently applied, and the danger attending them when not properly manufactured. Befide thefe practical obfervations, Mr. Magellan introduces no small share of philofophy; the fubject indeed requires it: and though his notes do not abound with what was before altogether unknown, yet by collecting, from various authors, the later difcoveries and improvements, and bringing them together in a regular manner, he hath rendered fcience a material fervice. Where he has difcovered errors, he hath corrected them; and where the opinions of former writers have been apparently oppofite or contradictory to each other, he has, by philofophical inveftigation, pointed out the cause of thefe difagreements, and reconciled them.

By way of Appendix, he has added a defcription of two portable laboratories for affaying minerals, and making chemical experiments on a fmall fcale. The apparatus is ingeniously contrived, and feems well calculated for making the intended trials.

A fecond Appendix contains feveral particulars useful to mineralogical enquirers, especially the method of analyfing earths and ftones, as given by Mr. Kirwan;-the defcription of an inftrument for finding fpecific gravities, by the very ingenious Mr. Nicholson; and an easy method of procuring accurate original weights.

The Effay on the Blow-pipe, by Mr. Engeftrom, is also added, and enriched with many notes, on the refults of experiments made with that inftrument, and the proper mode of ufing it.

*Thefe are all French measure,

REV. Jan. 1789.

Ꭰ

As