lake of Bavaria was bounded by two vaft chains of mountains of granite. One of these is a continuation of the mountains of Bohemia, extending, from the fouth-eaft to the north-weft, from the banks of the Danube near Paffau, to the mountains of Alface; the other runs from the south-west to the north-east, and is terminated on the north by the Fichtelberg.

On the Salt works in the Circle of Bavaria. By the Same. The works here defcribed are thofe of Hallein, in the principality of Saltzburg, of Bergtolfgaden, of Reichenhall and Trauenftein in the dutchy of Bavaria. At Hallein and Bergtolfgaden, the falt is found in its foffile flate; in order to obtain it, large cavities, called chambers, are dug in the mines, and filled with fresh water; fome of these are so large, that the water muft ftand in them during two years, before it is fufficiently impregnated with falt; in others, this procefs does not require more than a few weeks; when the water is saturated, it is carried through the mountain by pipes into a refervoir, whence it is conveyed to the cauldrons: of thefe, there are four at Hallein, and two at Bergtolfgaden, which are not above four leagues diftant from each other: the falt annually made, at the former of thefe places, amounts to four hundred thousand quintals, and, at the latter, to one hundred and fixty thoufand.

The fprings of Reichenhall are about four leagues from Bergtolfgaden, and are fuppofed to be impregnated with the falt of this mountain: they are twenty in number, but falt is made from only four of them: part of the water proceeding from them is conveyed by pipes to the cauldrons at Trauenftein, which is about three leagues diftant. The falt annually made from thefe fprings amounts to two hundred and fifty thoufand quintals.

The Count fuppofes that the mines at Hallein and Bergtolfgaden are parts of the fame bank of falt, which he thinks is a continuation of that at Gmund in Auftria, about eight leagues from Hallein; the irregularity of the ftrata feems to indicate that the connection, between the two mines hete described, must have been broken by fome violent revolution.

Concerning Coal. By the Same.

The Count diftinguishes this fofil into animal and vegetable; the former confifting of aquatic animals, the latter, of vegetable fubftances, converted into bitumen. These two claffes are difcriminated by the colour and quality of the afh; that of the animal coal is white, whereas that of the vegetable is ed; the former will effervefce with acids, but the latter will not. He acknowleges, however, that this divifion is not well fuited to a fyftem of mineralogy; and he obferves, that in this view, it will be more convenient to attend to external cha

racters,

racers, by which coal may be diftinguished into four fpecies. Thefe are, lithantrax Gagas, piceus, fchiflofus, and terreus: the firft of thefe is what is generally called Welch coal, and is very feldom found on the continent.

Memoir on Foffil Wood. By the Same.

The Count here defcribes nine fpecies of foffil wood found in Switzerland, most of which have been mentioned by Walle rius, in his Syftem of Mineralogy.

Defcription of a new Species of Stone. By the Same.

This tone is found at Rauwenftein in the Upper Palatinate, where it forms a bed forty fet and a half in depth, in which it lies in ftrata, each about two inches thick, and separated from that beneath it by a ftratum, two feet deep, of white mica, unmixed with quartzous particles. It has hitherto been confidered as a red quartz: but this academician maintains, that it is a ftone fui generis, to which he gives the name of fapphirine fpar. It is perfectly tranfparent, and of a changeable colour, which varies according to its pofition with refpect to the light: when this is reflected perpendicularly from its furface, it appears of a pile red: but, it placed on a dark foil, or feen in an oblique direction, it exhibits a fine blue. It is fo hard as to cut glafs; and the Count confiders it as a gem which ought to be claffed between the emerald and the oriental chryfolite.

On the Formation of Granite. By the Same.

The Count is of opinion that granite is formed by chryftal. lization, in order to which there must have been a previous folution of its fubftance in fome aqueous fluid. This fluid, he contends, could not be of the fame kind with that in which calcareous and argillaceous mountains were produced; for then the refults of the procefs would not have been diffimilar. Befide, neither fresh nor falt water is capable of perfectly diffolving quartzous earth. He therefore thinks it neceffary to fuppofe a chemical agent poflefling this property; fuch is the fluoric acid: hence he imagines that the earth was once covered with a vast ocean of this acid; that in it the vast quantity of quartz, of which our prefent mountains of granite were formed, was entirely diffolved; and that in confequence of the evaporation and concentration of this fluid, the cryftallization took place, to which he afcribes the production of the rocks. On this bold hypothefis we fhall leave our readers to make their own remarks.

Account of the Baths of Louëch. By Dr. LEVADE.

Thele baths are fituated in a deep valley, furiounded on the caft, weft, and north, by mountains; hence the temperature

of the air is remarkably mild, and the foil fertile: the Dala, which flows from the neighbouring glaciers, winds through the valley, and runs into the Rhone near Louëch.

The heat of the principal fpring is eftimated equal to fortythree degrees of Réaumur's thermometer. The baths are emptied, cleaned, and filled again every evening, that the water may cool during the night, and be ready for the bathers in the morning its temperature is thus reduced to about twentyeight degrees.

Thefe waters have no peculiar flavour either of fulphur or fixed air; and, notwithstanding their great heat, do not boil fooner on the fire than thofe of the coldeft fpring. The Doctor gives no chemical analyfis, but fays, that they abound with crocus martis; and he recommends the internal and external use of them in all thofe cafes in which warm mineral baths are usually prescribed.

Memoir concerning M. Born's Method of amalgamating Gold and Silver Ores. By Profeffor STRUVE.

In the year 1786, M. Born published at Vienna an account of his method of feparating gold and filver from the ore by amalgamation. Profeffor STRUVE here gives a fhort defcription of the procefs, and examines the principles on which its advantages are founded.

The difference between M. Born's method, and the common one, confifts in his directing the ore, after being washed and ground into a very fine powder, to be mixed with common falt, and roafted in a reverberating furnace. The Profeffor obferves that, by roafting the ore with falt, a double decompofition takes place, in confequence of which the vitriolic acid unites with the alkali of the falt, and the muriatic acid, combined with the metals, forms metallic falts. Hence more foluble falts are obtained, the vitriolic falts and acids are prevented from corroding the furface of the mercury, and the muriatic acid, being rendered elaftic, acts on the imperfect metals with greater efficacy, and calcines them with more ease. He thinks that to this agency of the muriatic acid, the principal advantage of M. Born's method may be afcribed: but he is of opinion that the procefs might be improved, by roasting the ore before the falt is added, and afterward triturating it with about a fixteenth part of falt and water.

The proportion of falt, which, according to M. Born, ought to be mixed with the ore, previously to the roafting, is about eight pounds to the hundred. The amalgamation is per

* See an account of a tranflation of this work, in the M. R. for June laft, New Series, vol. viii. p. 174.

formed

formed in copper veffels, over a gentle fire, by which the metal is heated to between fifty and fixty degrees of Réaumur's thermometer.

CHEMISTRY.

Analysis of the Waters of Amphion. By M. TINGRY.

The cold mineral fprings, here mentioned, are near Evian, on the fouthern banks of the lake of Geneva: the water contains calcareous earth, fixed air, and iron; the latter is fulpended but not diffolved in it.

AGRICULTURE.

Memoir on the proper Season for pruning Vines. By the Abbé BERTHOLON.

After fome obfervations on the advantages refulting from this operation, the academician inquires whether the spring or the autumn be the most proper season for performing it. If the climate be warm, and the vineyard fituated in a dry air and foil, he prefers the autumn: but, if the climate be cold, the foil damp, and the vines exposed to moift rainy weather, he thinks they may be pruned with greater fafety in the spring. However, in the latter cafe, he advifes to prune both in autumn and fpring; in the firft pruning, to leave the shoots about double the ufual length, and to cut them off closer in the following fpring. Thus all the advantages of autumnal pruning will be gained, and the danger avoided.

Defcription of a new Kind of Bee-hive. By M. DE GELIEU. This hive appears to be a fimple and ingenious contrivance, for which we are originally indebted to the inhabitants of Madagafcar. It may be conftructed of either ftraw or wood: but, as its internal dimenfions must be the fame throughout its whole length, it is neceffary that its form fhould be either cylindrical or prifmatic. Its principal advantage is, that its bafes are moveable, and may be fixed by pins at any distance from each other; by which means, its fize may be increased or diminished at pleasure. It must lie on its fide; and, in the foremost bafe, must be a paffage for the bees. Hence, by drawing out the pofterior base, the honey may be taken out of the back part of the hive, without hurting the bees; and, when this is done, the bafe fhould be pushed in clofe to the remaining comb, in order to avoid leaving any intermediate space. Another advantage is, that, by turning the hive, and making the entrance in that which had before been the pofterior base, the bees will build new cells, in the room of what had been taken away; in confequence of which, the honey will be more pure and white.

From

From the above account of the memoirs contained in this volume, taken in connection with thofe before published *, we leave our readers to form their own eftimate of the labours of this learned fociety. The inquiries of the philofopher are unavoidably influenced by the nature of the country which he inhabits, and by the fcenes with which he is converfant; it is therefore reasonable to expect that the members of this academy should bestow the chief of their attention on that part of natural hiftory, which, from the circumftances of their fituation, they have the moft favourable opportunities of cultivating. We cannot, however, avoid obferving, that there are other branches of science not lefs worthy of their notice, and the purfuit of which would afford more interefting information than the hypothetical conjectures and dry details of the mineralogift.

ART. II. Lettres Originales de MIRABEAU, &c. i. e. The Origi nal Letters of MIRABEAU, written from the Prison of Vincennes, during the Years 1777, 1778, 1779, and 1780; containing the Particulars of his private Life, his Misfortunes, and his Amours with Sophia Ruffei, Marquife de Monnier. Collected by P. Manvel, Citizen. 8vo. 4 Vols. Paris. 1792. Imported by De Boffe, London.

WE

E cannot help confidering the pofthumous publication of letters which were never intended for the prefs, as a grofs injury to the deceafed; and when this is done by one who calls himfelf a friend, it is a breach of confidence which renders him unworthy of the title. Perhaps M. MANUEL may think himself vindicated from this imputation, by alledging that MIRABEAU knew that he poffeffed thefe papers, and had only defired that the publication of them might be deferred till after his death: but, had he been infpired with that delicate and ftrict fenfe of honour, to which none but the man of confiftent virtue can pretend, he would have difdained the paltry pecuniary advantage that might refult from complying with the corrupt and vicious taste of his countrymen, and would not have been tempted to expofe fentiments and actions, which cannot but be injurious to the reputation of his departed friend, and unfavourable to the general interefts of morality. As friends to the virtue and happinefs of mankind, the fame principles that infpire us with an abhorrence of licentioufnefs and anarchy, animate us with a love of liberty, and with a warm approba. tion of those who endeavour to deliver their fellow-citizens

See Review, New Series, vol. iii. p. 545

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