fhaped by a chiffel. Our author means to examine it more particularly, but it is inacceffible, being too fteep to allow the fnow to rest on it.

In this fpot alfo there were no granites in mass, no vertical ftrata. The height of St. Theodule, and the rocks which our author vifited to the north above this point, were composed of alternate ftrata, a little inclined, of steatite, calcareous stone, and quartz. Among the ftones which fell from Mount Cervin, our author found only veined granites, and foliated rocks of quartz and mica; but the variety of colours in this natural obelifk fhows, that it probably contains fome other kinds. Its ftrata are not diftinct, though they are fo in the other parts of the chain, which forms as it were the fhoulders of this enormous Giant. Our author foon returned, and the mules feemed particularly eager to efcape from thefe icy regions. Nothing very particular occurred in his journey to Geneva, from whence he had been absent thirty-feven days. He returned the twen tieth of Auguft.

M. de Sauffure, in the continuation of his account, recapitulates the remarkable properties of Mount Rofe, which we need not follow; but we may add, from the conclufion, a few words refpecting the inhabitants of this country and their manners. The villages round the mountain are chiefly German, but the inhabitants now speak French and Italian. The origin of thefe Germans is unknown: they probably were inhabitants of the Upper Valais, who, on traverting the Alps, faw that the fummits of thefe valleys were not inhabited, and fixed on them, while the more effeminate inhabitants of Italy had not courage to lead their flocks or to vifit these apparently inhofpitable regions. The barren and ungrateful foil fcarcely farnishes them the conveniencies of life, and the men foon leave it, as the knowledge of three languages, which they may acquire in their infancy, fits them for travelling. The women remain almost wholly charged with the labours of agriculture. They alfo carry the burthens, and travel with great dexterity, avoiding the dangerous fpots, thus loaded, in places inacceffible to beafts. Their ftrength, their diligence, and their integrity are equally remarkable. They will carry a burthen fufficient to load two mules, and which a man can fcarcely lift, nor does this exceffive labour leffen their gaiety and fpirit. They accompanied our author; and, as they had no burthens, they ran on laughing, fpringing and leaping from the point of one rock to another, finging in the fhade till our travellers overtook them, when they again fet off with their usual veloeity and gaiety.

Sobriety, the ufual attendant of induftry, diftinguishes alfo thefe mountaineers. Their rye-bread, we have faid, is eaten only fix months after it is baked: they foften it in whey or butter-milk, and it makes their principal food; checfe, and a

7

little

little of the flesh of an old cow, or of a goat falted, for they are not fo extravagant as to eat fresh meat, are reserved for their festivals. The opulent live with the fame economy, and our author faw his hoft at Macugnaga, with great care unlock his cupboard, and take out every evening a little garlick, of which he distributed a clove to his wife and each child; and this was the only fauce to their hard bread, which they bruised between two ftones. Those who have travelled, and been used to better fare, return without murmuring or uneafinefs to their old diet. Their greatest fault is a want of hofpitality. They are unwilling to receive frangers; and, if they meet, endeavour to avoid them. Yet, after fome time the inhabitants of Macugnaga accofted our travellers in a friendly manner, and feemed flattered by the attention paid to their country. Since writing this Account,' M. Sauffure tells us, that he has feen the chevalier Roubilant's work on the Utility of Travelling in our own Country. It is published in 4to at Turin, and contains fix accurate views of Mount Rofe. Eight others of different mountains are added; but they are not illuftrated by descriptions.

We promifed to add to the account of M. Sauffure's travels, his fon's experiments for determining the density of the air at different heights. It is a work which reflects the highest honour on his talents, his ingenuity, and his industry. The air, it is well known, is condenfed very nearly in the ratio of the weight which preffes on it, and confequently its denfity ought to decreafe in a geometrical progreffion, while the heights increase in an arithmetical one; but it is not eafy to judge of the different density, without taking into the account the influences of heat and moisture, which, independently of the changes in the preffure, are the principal caufes of its variations. M. Bouguer, who, in calculating the height of mountains from the different heights of the mercury, took the difference of the logarithms correfponding to thefe different heights, found his conclufions accurate only within certain limits, for he made little allowance for a difference of heat, and none for the different state of moifture in the air. M. Bouguer then examined the denfity of the air by the motion loft by a pendulum vibrating at various heights, and enquired whether the refult found in this way, correfponded with thofe by the barometer. They feemed to do fo while the barometer ftood between 16 and 21 inches. After this, the relative density of the air diminished more and more, down to the height of 200 toifes above the level of the fea; it then went on increafing till he came to the fea. His conclufion was, that all the molecules of air had not an equal elasticity, and that the moft elastic ones gained the top of the atmosphere, leaving the lefs elaftic ones belew. In this ftate was our knowledge on the fubject, when M. Sauffure engaged in the examination.

M. Sauffure firit attempted to repeat Bouguer's experiments;

but

but various inconveniencies occurred with the pendulum, particularly on the mountains, when it was neceffary to attach the inftrument to fome part of the tent, which foon alfo began to vibrate and produce a combined motion. Thefe experiments, however, were kept in view, when made with every correction that could be employed, and they were of ule to compare with the others. Another method was, to weigh, at different heights, a balloon of glass accurately clofed; and M. M. Gruber and Gerstner's very tender balance, or the apparatus of M. Fouchy (Mem. de l'Academie, 1780) might have been employed with advantage. The time would not, however, admit of great preparation; and M. Sauffure was contented with his own balance, which vibrated fenfibly with half a grain. His globe was fealed hermetically, and fufpended by a hook of glafs; its form was that of a flattened elipfoid, whofe two diameters were 153 and 147.86 lines respectively; its folid contents 1053.95 cubic inches. When the thermometer (Reaumur's) was at 11, the hygrometer at 75, and the barometer at 27 inches, it weighed 18723 grains, and difplaced a bulk of air equal to 461.79 grains. If then the density of the air is expreffed by unity when the barometer is at 28 inches, the denfity at 27 inches will be =.06719. The balance was affected with a change of denfity equal to the thousandth part.

The influence of heat on the density of the air, is varied, ift. in proportion to its actual quantity, zdly, in proportion to the density of the ftratum on which it acts. The corrections are, therefore, determined by the height of the barometer, or that of the thermometer. Thefe two corrections may be fuppofed independent of each other, and probably are fo; but their mutual influence can at any rate produce no great error. From obfervation then, it appeared, that a difference of 25 degrees of heat comprehended between o and 25° of Reaumur, correfponds to a difference of 43.5 grains in the weight of the balloon, or to the 0.094199 part of the dentity, which is here equal to 99.28 cubic inches. M. Sauffure next, by the rule of proportion, determined the mean influence of a degree of the thermometer, for every 6 degrees; and the product of the quotient, by the number of degrees above or below 11.5, gives the nume ber of grains to be deducted or added to the weight found by, obfervation.

To obtain the second correction, he compared the effect of a certain number of degrees of the thermometer on the weight of the balloon at a given elevation, with the fame heat on the plain. At 27 inches, 5 degrees of heat between 10 and 15, correspond to 8.5 grains; at 24, to 9.35 grains, or the 0.022512th part of the density. A difference of 3 inches, therefore, produces one of c.85 grains, in the influence of 5 degrees of heat. It would have been curious to have feen whether this correction would

have

have been proportionally the fame at different heights; but is the highest ftations, the variations of heat are not fufficiently confiderable.

The most direct method of knowing the influence of moisture, independent of heat and the height of mercury in the barometer, is to choose a spot where the laft circumstances continue uns altered, while the moisture of the air varies. It follows, from thefe obfervations, that humidity diminishes the density of the air, and that a difference of 10 degrees of the hygrometer, be tween 65 and 9, correfponds to the difference of a grain in the weight of the balloon; and that the height of the mercury does not influence it. At the 19th degree, our author thinks the denfity of the air requires no correction for the moisture, fince it is as heavy as at 75° of the hygrometer. This obfervation agrees very well with the range of the barometer, in which the mercury always rifes when it begins to rain.'

To judge if the densities found by the balloon were proportional to the preffures indicated by the barometer, our author endeavoured to determine, independent of obfervation, the relation which ought to prevail between the weight of the volume of air displaced by the balloon, and the correfponding height of the mercury, fuppofing the denfities proportional to the preffure. On comparing the refult of this enquiry with experiments, it appears that the denfities are always in proportion to the pres fures, if the corrections above mentioned are employed.

In the higher parts of the atmosphere, where the heat varies but little, or where it is much less than in the plain, the influence is confequently lefs, and the denfities will appear in proportion to the preffure, without making any correction for the heat, as M. Bouguer found. In the lower part of the atmosphere the fame relations will not be equally confpicuous. As the fame degree of hear, therefore, has so much less influence on the denfiry of a ftratum of air, in proportion as that stratum is lower, we ought to find, cæteris paribus, the denfity proportionally lefs great as we approach the level of the fea; and this feems to have occurred to M. Bouguer: fo that his theory is erroneous, and the variations in his experiments evidently proceed from his not attending to the heat, or perhaps from the inaccuracy with which he made them. Our author adds the particulars of his experiments with the pendulum, in which he fuppofes that the lofs of motion in a given time, is proportional to the denfity, and this implies a propofition not clearly demonstrated, that the refiftance of the air increases as the fquare of the velocities. Our author adds alfo the refult of his experiments with the balloon, as well as examples to fhow, that with the neceffary corrections, thefe experiments are confiftent with the general principle of the denfity, being in proportion to the preffure.

F 0.

FOREIGN ARTICLE.

Tableau Generale de la Suede. Par M. Catteau. 8vo. 2 Tomes. Laufanne.

SWEDEN was for many years the arbitres of Europe; and the fuccefs with which the, for a time, refifted the vast power of Ruffia, has rendered her an interefting object at this period. It was long fuppofed that he could never recover the exertions which the extravagant ambition of Charles XII. had occafioned. Our author draws this picture only after having refided fome time in Sweden, and concludes his preface with the following animated apostrophe to its inhabitants.

• Swedes, with whom I have long refided, to you I offer this work: the most fcrupulous impartiality has guided my pen. I have written what my eyes have feen, my mind perceived, and my heart felt. You know that every human fociety has its im perfections: by unfolding them, without feverity, we lead gently to a correction. In other refpects, I am ambitious of your efteem; and I should only have been contemptible in your eyes if flattery had induced me to betray the interests of truth.'

The eleven chapters of the first volume relate to the Geography and the Philofophical History of Sweden; its civil hiftory, name, arms, title of its king, his coronation, court, family, refidence, and villas; the connection of the kingdom with foreign powers, its conftitution internal and external, adminiftration, religion, civil and criminal laws, military establishments and orders of knighthood, the revenues and expences of the

crown.

Sweden was a part of the vast country which the Romans formerly called Scandinavia. It is divided into five parts, which, together, form the largest kingdom in Europe next to Ruffia. The winter is long, dry, and very cold; the fummer fhort and extremely hot. Thefe two feafons fucceed each other with fcarcely any interval, for fpring and autumn are almost wholly unknown. The moon, the aurora borealis, and the reflection of the fnow, enliven the long nights of winter with a mild and agreeable light. In fummer, the fun hangs fo long on the horizon, that night confifts only in a flight twilight. Then nature regains its vigour, and feems to compenfate for her long inactivity. Though placed almoft under the arctic circle, the climate is milder than in the correfponding latitudes of Afia and America, owing, as our author fuppofes, to the fea, by which it is interfected, but more probably to its degree of cultivation. Thunder, venomous animals, and earthquakes, are uncommon; even of the fufpected volcanos of a former æra, our author thinks the proofs not fatisfactory. The pure elastic air renders the Swedes long-lived, free from epidemics, and in general healthy. According to a memoir of M. Vargentin, in a late æra, during a period of from nine to ten years, there VOL. LXX, Nov. 1799.

૦ ૧

were