four English miles, or one-eighth part of the whole too great. Experience has taught the navigators, that they come too foon down upon Anholt; or that they, cruifing between Anholt and Sweden, overrun their reckoning, which was afcribed to the currents; although the true reafon of it was the great error in the geographical and hydrographical pofition of Anholt in a narrow and dangerous paffage.' Investigations, founded on the Theory of Motions, for determining the Times of Vibration of Watch Balances. By George Atwood, Efq. F. R. S.

Inftrumenes for measuring time by vibrating motion were invented about the beginning of the 16th century: but, though the pendulum was used before this period, and was known to be a very exact meafure of time, it was not combined with clockwork till the year 1657, when Mr. Huygens applied it to this ufeful purpose. The honour of the invention has, indeed, been contefted. Some have afcribed it, as our author does, to Huygens, and others have urged the claims of Galileo. It is not improbable that in this, as well as in many other instances, the discovery of the one was independent of that of the other. It appears, however, from various accounts, that the balance was univerfally adopted in the conftruction of the first clocks and watches: - but, as the balance was made to vibrate merely by the impulses of the wheels, without any other controul or regulations, its vibrations must have been unsteady and irregular. To Dr. Hooke's ingenious invention of applying a spiral (pring to the balance, in 1658, we are indebted for the remedy of thefe imperfections; as the action of this spring on the balance of a watch is fimilar to that of gravity on the pendulum, by which it ferves to correct the irregularities of impulse and refiftance, that would otherwife difturb the ifochronifm of the vibrations. In the modern improvements of time-keepers, principally devised and executed by the artists of our own country, the irregular forces, both of impulfe and refiftance, are greatly diminished by the accuracy, with refpect both to form and dimenfion, with which the various parts of the machines are conftructed; and they are farther corrected by the maintaining power derived from the main fpring: for, whatever motion is loft by the balance from resistance of any kind, almoft the fame motion is communicated by the maintaining power, fo as to continue the arc of vibration, as nearly as poffible, of the fame length. In thefe important and ufeful machines, the real mealure of time is the balance,' the other parts ferving only to preferve its motion, and to indicate the time measured by its vibrations. The regularity of a time-keeper must therefore chiefly depend on that of the time in which the balance vibrates. The object of the ingenious Mr. Atwood, in this paper, is to investigate

investigate the time of vibration by means of the theory of motion, from the feveral data or previous conditions on which it depends. What thefe data are he first enumerates; and he then investigates, by mathematical proceffes, which admit of no abridgement, the vibration of a balance impelled by a fingle fpiral fpring and that occafioned by two or more springs. The latter investigation is applied to the folution of fome cafes which occur in confidering the conftruction of Mr. Mudge's time-keeper. In this machine, no force nor impulfe whatever is communicated to the balance from the main fpring; and yet the vibrations are continued of their due length, and the maintaining power, by which the motion of the balance is preferved, is always uniformly the fame. The accomplishment of this object to its full extent, in the conftruction of watches, our author afcribes to the ingenuity of Mr. Mudge. It is alfo a farther advantage, pertaining to the conftruction of this excellent artift, that the balance is perfectly detached from the wheelwork of the machine; the only communication between the balance and the balance- wheel being that which fubfifts while the pallet is difengaged from the tooth; and this is an inftant of time, which, in a practical fenfe, is almost evanefcent.

For other obfervations on the construction of time-keepers in general, and on that of Mr. Mudge in particular, we must refer the reader to the paper itself.

[To be concluded in the next Review.]

ART. XIV. A Picturesque Tour from Geneva to the Pennine Alps. Tranflated from the French. Folio. pp. 16. 12 Plates. 51. 5s. Boards. Bate, Cornhill.

W HEN a writer is tranflating an anonymous foreign work, it may fuffice to mention the language in which it was originally written: but if the production bears in its title page the name of its author, the tranflator acts at least unhandfomely if he conceals it: more efpecially when the original publication is of great price and merit. What inducement the English editor of the prefent work, and of the Hiftorical and Picturefque Defcription of the County of Nice*, (fee M. Rev. New Series, vol. x. p. 308,) which it follows en fuite, could have for practifing this concealment, we are at a lofs to conjecture; fince the exhibition of the name of the author muft rather have affifted than hindered its fale: yet the prefent exquifitely beautiful engravings, coloured from nature to imitate drawings, and the itinerary with which they are accompanied, have not one line in the form of advertisement, preface, or note, to fatisfy the most

When we reviewed that work, its prototype did not occur to us.

obvious

obvious and neceffary inquiries. All that we are told of this picturesque tour is that it is tranflated from the French. In the explanation of the plates, we find a reference to a foregoing work,' which we understand to be the above-mentioned Defcription of Nice: but there is nothing to convey this information to those who never heard of, or may not recollect, that volume.

While we announce this fplendid publication, and acknowlege the amufement and inftruction which we have derived from it, we must not omit to do juftice to the author, to whofe accurate pencil we owe the exhibition of thefe most fublime and ftriking scenes, and whose pen has been employed in affifting the inquifitive traveller to explore them. The prefent is the tranflation of a work printed at Geneva in the year 1787, under the following title; Voyage Pittorefque aux Alpes Pennines, précédé de quelques obfervations fur les hauteurs de montagnes, glaciers, des différens villages, qui fe trouvant fur cette route. Suivi de quelques notes pour fervir d'explication aux deffeins qui compofent cet ouvrage. Dédié à Son Alteffe Royale La Princeffe Sophie Matilde de Gloucefter. Par Albanis Beaumont, Ingenieurpenfionné de Sa Majefié le Roi de Sardaigne,& Profeffeur en Mathematiques et Fortification de Son Aiteffe Royale le Prince Guillaume de Gloucester.

Whether the English Editor of this and the foregoing work be in poffeffion of the original copper plates, or whether he has only a certain number of the French copies, which he has endeavoured to prepare for the English market by prefixing to each a translation of the original letter-prefs, it is not within our province to inquire.

Waiving all farther regard to the hiftory of the publication, we proceed to speak of it as it prefents itfelf to our examination. In fome inftances, the tranflator has either not understood his fubject, or has been negligent in performing his duty. We were furprized to fee Mont-Blanc,to which, as making one proper name, the English ear is accuftomed,-rendered throughout the work the Mount-Blanc :-Here the article is as unneceffary as before Aina or Vefuvius. Parts of fentences we find occafionally omitted; and in one place one of the names of a particular glacier, and by which alone it is pointed out in the explanation of the plates; fo that no one could fuppofe, from the English work, that le Glacier de Bois and that called Mer de Glace was the fame. Sometimes the verfion is bald, as when the tranflator renders justement vifitée juftly vifited,' and chaque paffant jette une pierre fur leur fepulture, every pallenger throws a ftone upon their fepulture,' instead of on their grave. On the whole, however, the tranflation is faithful; and the ac

counts

counts of the mountains and glaciers, compofing the region undertaken to be defcribed, when affifted by the pictorial representations of the fublime beauties which it contains, muft render this a moft interefting and valuable publication. Drawings and engravings we cannot copy: but we can and will indulge our readers with the description of le Glacier de Bois or Mer de Glace, and le Montanverd, or Green Mountain:

The second day at Chamouni is usually employed in a visit to the Valley of Ice, and to attain which it is neceffary to afcend the Montanverd, or Green Mountain, so called from its verdure. I fhall not undertake to describe the beauty of that enormous glacier called Le Glacier de Bois (in the French it is added, ou Mer de Glace) or the fenfations I experienced at the fight of it. No better idea can be conveyed to the mind than by imagining a ftormy fea fuddenly furprized by a frost.

• The mountains which furround the valley are, ift, Mount Charmos on the right; 2d, Mount Mallet in the back ground; 3d, Perfades; 4th, the Great Jorra, of an extraordinary height; 5th, l'Aiguille du Moine; 6th, that of Dru, which is oppofite to the little hermitage, where people commonly ftop to dine on the provisions they carry with them. This mountain (Montanverd) is very curious, being half covered with ice and fnow, and, in intermediate spaces, with excellent paftures, where cattle feed.

Although it be difficult to ascertain the length and breadth of the fea of ice, as objects appear nearer on high mountains than in valleys, where the air is more denfe, yet it may fairly be conjectured to be three quarters of a league broad and five leagues long; that is to fay the space which the eye comprehends from Montanverd; for the fea of ice may extend about twelve leagues.—

A more curious, and at the fame time a more dreadful scene than this cannot be conceived, at once prefenting the image of the frozen fea and the verdure of the temperate zone. It is poffible to defcend from the Montanverd on the sea of ice and even to cross it, but the dangers are many on account of the large crevices which it is neceffary to step over, that are more than an hundred feet deep; however, I did it myself. It is matter of much furprize, on coming to this place, to find the waves, which at some distance appear inconfiderable, to be more than eighty or an hundred feet in height.

From Blair's Hofpital there is a very steep and narrow path, through a forest of firs and larches, which takes about an hour to defcend, in order to return to a place on a level with the Priory, where there is a little wooden bridge to cross over the Arveron (l'Arve); when another most aftonishing object prefents itself, an entire mountain of ice, formed by the fall of the glacier, feen from the Montanverd, which defcends into the valley. High mountains of granite furround thefe glaciers, and form, by their irregular strata, fuperb cafcades, mixing their waters with the Arveron, which iffues from a moft beautiful grotto above an hundred feet high, compofed entirely of ice. The wonderful effects of maffes of ice contrafted with the impending woods and rich pastures that crown this grand and uncommon

fcene,

fcene, added to the frightful noife fo frequently heard of enormous bodies of it breaking off from the mountain and dafhing themselves to pieces in the Arveron, muft create an admiration and furprize more readily felt than expreffed.'

The plates are beautifully executed but, when drawings undertake to reprefent bodies of vaft and unusual magnitude, fuch as Mont-Blanc and Glaciers, they as much require the affistance of verbal description to imprefs our minds with a fenfe of their vaftnefs, as the verbal defeription ftands in need of the pencil of the artift to produce an accurate conception of outline and arrangement of parts.

If, on reviewing the author's accounts and views of the County of Nice, we longed to enjoy the delightful region and climate which he there defcribes, we are equally tempted by his present work to wish that, before our mortal journey be brought to an end, we could explore the wonders of the Pennine Alps, and participate in that awful and philofophic pleasure which must be excited amid fuch august and romantic fcenery.

ART. XV. Picturefqne Views on the River Medway, from the Nore to the Vicinity of its Source in Suffex: with Obfervations on the Public Buildings and other Works of Art in its Neighbourhood. By Samuel Ireland. Large 8vo. pp. 206, and 29 Plates. 11. 11s. 6d. Boards. Egertons. 1793.

LE

Es Voyages pittoresques of the French have given birth to many elegant and amufing publications in our own country; among which thofe of Mr. Ireland are certainly not unworthy of being claffed. Of his Picturefque Tour through Holland, &c. and of his Picturefque Views on the River Thames, we have given fome account in our New Series, vol. v. p. 93, and vol. xii. p. 51; and we have now to inform our readers that, in confequence of the marriage which poetry records (and who will fo impeach his taste or his gallantry as to question the teftimony?) to have taken place between the Lady Medway and the old River God Thames, Mr. Ireland is induced to offer this publication, not as a distinct undertaking, but as a continuation of his former work. Having exhibited the attractions of the hufband, he haftens to do juftice to the beauties of the bride: but, instead of beginning at the fource, (as in his account of the Thames,) and following the Medway downward to its confluence with the former, he commences at the Nore, and traces it upward to its fource. By thefe means, the two works may be made to include one aquatic tour; and the beauties of art and nature, on which the pencil has been employed, may be explored by thofe who are difpofed REV. JAN. 1795.

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