four English miles, or one-eighth part of the whole too great. Exper rience 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. Inftruments 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 measure 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 inftances, the difcovery of the one was independent of that of the other. It appears, however, frem 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 impulfes of the wheels, without any other control or regulations, its vibrations must have been unfteady and irregular. To Dr. Hooke's ingenious invention of applying a fpiral fpring to the balance, in 1658, we are indebted for the remedy of thefe imperfections; as the action of this fpring on the balance of a watch is fimilar to that of gravity on the pendulum, by which it ferves to correct the irregularities of impulfe and refiftance, that would otherwife difturb the ifochronifm of the vibrations. In the modern improvements of time-keepers, principally devised and executed by the artifts 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 Constructed; 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 measure of time is the balance,' the other parts ferving only to preferve its motion, and to indicate the time meafured 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 inveftigate inveftigate the time of vibration by means of the theory of motion, from the feveral data or previous conditions on which it depends. What these 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 fprings. 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 preserved, 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 also 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 instant of time, which, in a practical fenfe, is almoft 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.] Re.s. ART. XIV. A Picturesque Tour from Geneva to the Pennine Alps. WHEN When we reviewed that work, its prototype did not occur to us. obvious obvious and neceffary inquiries. All that we are told of this picturefque 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 amusement and instruction which we have derived from it, we must not omit to do justice to the author, to whofe accurate pencil we owe the exhibition of thefe moft fublime and ftriking fcenes, and whofe pen has been employed in asfifting 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 trouvent 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 Majefte le Roi de Sardaigne, Profeffeur en Mathematiques et Fortification de Son Aiteffe Royale le Prince Guillaume de Gloucefter. 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 tranflation 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 Etna 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 visitée juftly vifited,' and chaque paffant jette une pierre fur leur fepulture, every paffenger throws aftone upon their fepulture,' inftead 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 reprefentations of the fublime beauties which it contains, must render this a moft interefting and valuable publication. Drawings and engravings we cannot copy: but we can and will indulge our readers with the defcription of le Glacier de Bois or S Mer de Glace, and le Montanverd, or Green Mountain: The fecond day at Chamouni is ufually employed in a vifit to the Valley of Ice, and to attain which it is neceffary to afcend the Montanverd, or Green Mountain, fo called from its verdure. I fhall not undertake to defcribe 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 fur prized by a froit.— The mountains which furround the valley are, ift, Mount Charmos on the right; 2d, Mount Mallet in the back ground; 3d, Periades; 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 now, and, in intermediate spaces, with excellent paftures, where cattle feed. Although it be difficult to afcertain 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 fea of ice and even to cross it, but the dangers are many on account of the large crevices which it is necessary to ftep over, that are more than an hundred feet deep; however, 1 did it myself. It is matter of much furprize, on coming to this place, to find the waves, which at fome diftance 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 (re); 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 ftrata, fuperb cafcades, mixing their waters with the Arveron, which iffues from a most beautiful grotto above an hundred feet high, composed entirely of ice. The wonderful effects of maffes of ice contrafted with the impending woods and rich paftures that crown this grand and uncommon fcene feene, added to the frightful noife fo frequently heard of enormous bodies of it breaking off from the mountain and dashing 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 unufual magnitude, 'fuch as Mont-Blanc and Glaciers, they as much require the affiftance of verbal defcription to imprefs our minds with a fenfe of their vaftness, as the verbal defcription 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 prefent work to with 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 pleafure which must be excited amid fuch auguft and romantic feenery. Moo-y. 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. 1. 11s. 6d. Boards. Egertons. 1793. own L Es Voyages pittorefques of the French have given birth to to |