artists, will enable him to acquire with facility, and to employ with advantage, the detached and partial ideas of beauty which will be exhibited to his view in a survey of nature in her actual state. When he discovers these partial beauties, he will be capable of combining them with those perfect forms of beauty with which he is already acquainted. In a word, by having always present to his mind the noble models already mentioned, he will be in some measure his own oracle, and will draw rules from his own mind.

There are, however, two ways of imitating nature. In the one a single object occupies the artist, who endeavours to represent it with precision and truth; in the other, certain lines and features are taken from a variety of objects, and combined and blended into one regular whole. All kinds of copies belong to the first kind of imitation; and productions of this kind must be executed necessarily in the Dutch manner, that is to say, with high finishing, and little or no invention. But the second kind of imitation leads directly to the investigation and discovery of true beauty, of that beauty whose idea is connate with the human mind, and is only to be found there in its highest perfection. This is the kind of imitation in which the Greeks excelled, and in which men of genius excite the young artists to excel after their example, viz. by studying nature as they did.

After having studied in the productions of the Grecian masters their choice and expression of select nature, their sublime and graceful contours, their noble draperies, together with that sedate grandeur and admirable simplicity that constitute their chief merit, the curious artists will do well to study the manual and mechanical part of their operations, as this is absolutely necessary to the successful imitation of their excellent.

manner.

It is certain that the ancients almost always formed their first models in wax: to this modern artists have substituted clay, or some such composition: they prefer clay before wax in the carnations, on account of the yielding nature of the latter, and its sticking in some measure to every thing it touches. We must not, however, imagine from hence that the method of forming models of wet clay was either unknown or neglected among the Greeks: on the contrary, it was in Greece that models of this kind were invented. Their author was Dibutades of Sicyon; and it is well known that Arcesilas, the friend of Lucullus, obtained a higher degree of reputation by his clay models than by all his other productions. Indeed, if clay could be made to preserve its original moisture, it would undoubtedly be the fittest substance for the models of the sculptor; but when it is placed either in the fire or left to dry imperceptibly in the air, its solid parts grow more compact, and the figure losing thus a part of its dimensions, is necessarily reduced to a smaller volume. This diminution would be of no consequence did it equally affect the whole figure, so as to preserve its proportions entire. But this is not the case for the smaller parts of the figure dry sooner than the larger; and thus losing more of their dimensions in the same space of time than the latter do, the symmetry and proportions of the figure inevitably suffer. This inconveniency does not take place in those models that are made in wax. It is indeed extremely difficult, in the ordinary method of

working the wax, to give it that degree of smoothness that is necessary to represent the softness of the carnations or fleshy parts of the body. This inconvenience may, however, be remedied, by forming the model first in clay, then moulding it in plaster, and lastly casting it in wax. And, indeed, clay is seldom used but as a mould in which to cast a figure of plaster, stucco, or wax, to serve henceforth for a model by which the measures and proportions of the statue are to be adjusted. In making waxen models, it is common to put half a pound of colophony to a pound of wax; and some add turpentine, melting the whole with oil of olives.

50

ble, and

So much for the first or preparatory steps in this Method of procedure. It remains to consider the manner of work-working ing the marble after the model so prepared; and the method here followed by the Greeks seems to have been extremely different from that which is generally observed by modern artists. In the ancient statues we find the most striking proofs of the freedom and boldness that accompanied each stroke of the chisel, and which resulted from the artist's being perfectly sure of the accuracy of his idea, and the precision and steadiness of his band: the most minute parts of the figure carry these marks of assurance and freedom; no indication of timorousness or diffidence appears; nothing that can induce us to fancy that the artist had occasion to correct any of his strokes. It is difficult to find, even in the second-rate productions of the Grecian artists, any mark of a false stroke or a random touch. This firmness and precision of the Grecian chisel was certainly derived from a more determined and perfect set of rules than those which are observed in modern times.

The method generally observed by the modern sculptor is as follows: First, out of a great block of marble he saws another of the size required, which is performed with a smooth steel saw, without teeth, casting water and sand thereon from time to time; then he fashions it, by taking off what is superfluous with a steel point and a heavy hammer of soft iron; after this, bringing it near the measure required, he reduces it still nearer with another finer point; he then uses a flat cutting instrument, having notches in its edge; and then a chisel to take off the scratches which the former has left; till, at length, taking rasps of different degrees of fineness, by degrees he brings his work into a condition for polishing.

After this, having studied his model with all possible attention, he draws upon this model horizontal and perpendicular lines which intersect each other at right angles. He afterwards copies these lines upon his marble, as the painter makes use of such transversal lines to copy a picture, or to reduce it to a smaller size. These transversal lines or squares, drawn in an equal number upon the marble and upon the model, in a manner proportioned to their respective dimensions, exhibit accurate measures of the surfaces upon which the artist is to work; but cannot determine, with equal precision, the depths that are proportioned to these surfaces.— The sculptor, indeed, may determine these depths by observing the relation they bear to his model; but as his eye is the only guide he has to follow in this estimate, he is always more or less exposed to error, or at least to doubt. He is never sure that the cavities made

by

by his chisel are exact; a degree of uncertainty accompanies each stroke; nor can he be assured that it has carried away neither too much nor too little of his marble.

It is equally difficult to determine, by such lines as have already been mentioned, the external and internal contours of the figure, or to transfer them from the model to the marble. By the internal contour is understood that which is described by the parts which approach towards the centre, and which are not marked in a striking manner.

It is farther to be noticed, that in a complicated and laborious work, which an artist cannot execute without assistance, he is often obliged to make use of foreign hands, that have not the talents or dexterity that are necessary to finish his plan. A single stroke of the chisel that goes too deep is a defect not to be repaired; and such a stroke may easily happen, where the depths are so imperfectly determined. Defects of this kind are inevitable, if the sculptor, in chipping his marble, begins by forming the depths that are requisite in the figure he designs to represent. Nothing is more liable to error than this manner of proceeding. The cautious artist ought, on the contrary to form these depths gradually, by little and little, with the utmost circumspection and care; and the determining of them with precision ought to be considered as the last part of his work, and as the finishing touches of his chisel.

The various inconveniences attending this method determined several eminent artists to look out for one that would be liable to less uncertainty, and productive of fewer errors. The French academy of painting at Rome hit on a method of copying the ancient statues, which some sculptors have employed with success, even in the figures which they finished after models in clay or wax. This method is as follows. The statue that is to be copied is inclosed in a frame that fits it exactly. The upper part of this frame is divided into a certain number of equal parts, and to each of these parts a thread is fixed with a piece of lead at the end of it. These threads, which hang freely, show what parts of

the statue are most removed from the centre with much more perspicuity and precision than the lines which are drawn on its surface, and which pass equally over the higher and hollow parts of the block: they also give the artist a tolerable rule to measure the more striking variations of height and depth, and thus render him more bold and determined in the execution of his plan.

But even this method is not without its defects: for as it is impossible, by the means of a straight line, to determine with precision the procedure of a curve, the artist has, in this method, no certain rule to guide him in his contours; and as often as the line which he is to describe deviates from the direction of the plumb line, which is his main guide, he must necessarily feel himself at a loss, and be obliged to have recourse to conjecture.

This

It is also evident, that this method affords no certain rule to determine exactly the proportion which the various parts of the figure ought to bear to each other, considered in their mutual relation and connections. The artist, indeed, endeavours to supply this defect by intersecting the plumb-lines by horizontal ones. resource has, nevertheless, its inconveniences, since the squares formed by transversal lines, that are at a distance from the figure (though they be exactly equal), yet represent the parts of the figure as greater or smaller, according as they are more or less removed from our position or point of view. But, notwithstanding these inconveniences, the method now under consideration is certainly the best that has hitherto been employed: it is more practicable and sure than any other we know, though it appears, from the remarks we have now been making, that it does not exhibit a sure and universal criterion to a sculptor who executes after a model.

52

statue.

To polish the statue, or make the parts of it smooth of polishand sleek, pumice-stone and smelt are used; then tri-ing the poli; and when a still greater lustre is required, burnt straw is employed. For the Casting of Statues, see FOUNDERY, and PLASTER of Paris. See also ARTS, FINE, SUPPLEMENT.

SCU

SCUM, properly denotes the impurities which a liquor, by boiling, casts up to the surface. The term scum is also used for what is more properly called the scoria of metals.

SCUPPERS, in a ship, are certain channels cut through the water-ways and sides of a ship, at proper distances, and lined with plated lead, in order to carry the water off from the deck into the sea. The scuppers of the lower deck of a ship of war are usually furnished with a leathern pipe, called the scupper-hose, which hangs downward from the mouth or opening of the scupper. The intent of this is to prevent the water from entering when the ship inclines under a weight of

sail.

SCURVY, in Medicine, see that article, N° 351. where we have given an account of the symptoms, causes, and modes of prevention and cure, according to some of the most eminent writers in medicine. We have here only to add, that, in the opinion of Dr Beddoes, the mineral acids, especially the nitric and vitriolic, may

SCU

Scute.

be employed in the prevention or cure of this dreadful Scurvy disease with as much success as the vegetable acids.But of all the substances that can at once be cheaply procured and long preserved, he thinks the concrete acid of tartar by far the most promising. It is very grateful, and comes near to the citric acid. In tropical countries the scurvy is seldom known.

SCURVY-Grass. See COCHLEAREA, BOTANY Index. SCUTAGE (scutagium, Sax. scildpening), was a tax or contribution raised by those that held lands by knights service, towards furnishing the king's army, at one, two, or three merks for every knight's fee. Henry III. for his voyage to the Holy Land, had a tenth granted by the clergy, and scutage, three merks of every knight's fee, by the laity. This was also levied by Henry II. Richard I. and King John. See KNIGHT-Service.

SCUTE, (scutum), a French gold coin of 3s. 4d. in the reign of King Henry V. Catharine queen of England had an assurance made her of sundry castles, manors, lands, &c. valued at the sum of 40,000 scutes,

Suther

land's Tour up the

Straits,
Letter xii.

every two whereof were worth a noble. Rot. Parl. 1. Hen. VI.

SCUTELLARIA, SKULL-CAP, a genus of plants, belonging to the didynamia class; and in the natural method ranking under the 4th order, Personate. See BOTANY Index.

SCUTTLES, in a ship, square holes cut in the deck, big enough to let down the body of a man, and which serve upon some occasions to let the people down into any room below, or from one deck to another.

SCYLAX, a celebrated mathematician and geographer of Caria, flourished under the reign of Darius Hystaspes, about 558 B. C. Some have attributed to him the invention of geographical tables. We have under his name a geographical work published by Hoeschelius; but it is written by a much later author, and is perhaps only an abridgement of Scylax's Ancient Geography.

SCYLLA, in Ancient Geography, a rock in the Fretum Siculum, near the coast of Italy, dangerous to shipping, opposite to Charybdis, a whirlpool on the coast of Sicily; both of them famous in mythology.

Scylla and Charybdis have been almost subdued by the repeated convulsions of this part of the earth, and by the violence of the current, which is continually increasing the breadth of the straits. If proper allowance be made for these circumstances, we shall acquit the ancients of any exaggeration, notwithstanding the very dreadful colours in which they have painted this passage. It is formed by a low peninsula, called Cape Pelorus, stretching to the eastward on the Sicilian side, immediately within which lies the famous whirlpool of Charybdis, and by the rocks of Scylla, which a few miles below on the Calabrian shore project towards the west. The current runs with surprising force from one to the other alternately in the direction of the tide, and the tides themselves are very irregular. Thus vessels, by shunning the one, were in the utmost danger of being swallowed up by the other.

At present, in moderate weather, when the tide is either at ebb or flood, boats pass all over the whirlpool : but, in general, it is like the meeting of two contending currents, with a number of eddies all around; and, even now, there is scarcely a winter in which there are not , some wrecks.

"At the time when we passed the straits (says Captain Sutherland, from whom we have obtained this accurate information) the weather was as favourable as we could wish; and yet in spite of a strong breeze and the current, which hurried us on with surprising velocity, the ship's head was suddenly whirled round near three points; but the wind blowing fresh, in a few seconds she dashed through the eddy that had caught her; for, to avoid Scylla, and secure Messina, we had kept pretty close to Charybdis." For a later account of these rocks, see SICILY.

SCYROS, an island in the gean sea, at the distance of about 28 miles north-east from Euboea. It is 60 miles in circumference. It was originally in the possession of the Pelasgians and Carians. Achilles retired there to avoid going to the Trojan war, and became father of Neoptolemus by Deidamia the daughter of King Lycomedes. Scyros was conquered by the Athenians under Cimon. It was very rocky and barren. Now Sciro. E. Long. 25. o. N. Lat. 38 15.

SCYTALA LACONICA, in antiquity, a stratagem or

I

device of the Lacedæmonians, for the secret writing of Seytala letters to their correspondents, so that if they should chance to be intercepted, nobody might be able to read Scythe. them. To this end they had two wooden rollers or cylinders, perfectly alike and equal; one whereof was kept in the city, the other by the person to whom the letter was directed. For the letter, a skin of very thin parchment was wrapped round the roller, and thereon was the matter written; which done, it was taken off, and sent away to the party, who, upon putting it in the same manner upon his roller, found the lines and words in the very same disposition as when they were first written. This expedient they set a very high value on; though, in truth, artless and gross enough: the moderns have improved vastly on this method of writing. See CIPHER.

SCYTALIA, a genus of plants belonging to the oc tandria class; and in the natural method ranking with those that are doubtful. See BOTANY Index.

SCYTHE, in Husbandry, a well known instrument which has been long employed for cutting grass for hay. The same instrument with certain modifications in its construction has been used in reaping grain, in place of the sickle, the use of which is far more common, and in Scotland at least prevails almost universally, although it must be admitted that the method of reaping by the scythe, where it is practicable, is attended with less labour, is more expeditious, and therefore more economical. But against the use of the scythe, as a reaping instrument, many objections have been raised. Some of these are probably founded in prejudice, while others, considering the slow progress which has been made in introducing this instrument as a substitute for the sickle, rest on a more solid foundation.

It is said that this instrument shakes the ear, so that many of the grains are lost; that it lets the corn fall after it is cut, in a scattered confused manner, in consequence of which either a great deal of it is lost, or much time is wasted in gathering it together. It is also affirmed that it can only be made use of in very even land, and which is free from stones; that it does not leave length enough of stubble on the ground, on which to lay the corn when it is cut; that it mixes noxious weeds with the corn, the seeds of which are sown the ensuing year; and finally, that the use of the scythe is prejudicial to the health of the reaper.

It appears, however, that these objections have either no weight, or they are made by those who are unacquainted with the scythes peculiarly adapted to this purpose, and with the manner in which they ought to be used. With a good scythe properly managed, the corn when cut, remains at first upright, afterwards falling gently on the rake fixed to the scythe, without any shaking or jolting, or at least with less than what is occasioned by the sickle. The loss of grain chiefly arises from the corn being too dry, and therefore it ought to be reaped on proper days, and suitable times of the day, which is more easily accomplished by the scythe than the sickle, because the one requires less time than the other. The stalks, held together by the rake, may be laid on the ground, or against the corn not yet cut down, in a state so regular and connected, that those by whom the sheaves are collected and bound have themselves alone to blame, should any thing be left behind. It is sufficiently even when lands are ploughed and barrowed

Scythe rowed in a proper manner; and the only necessary precaution in stony ground, is to keep the scythe a little higher, that it may not strike against the stones. If the stubble be short, the straw cut off will of course be the longer, and of consequence more valuable; and long stubble only incommodes the cattle afterwards sent to feed upon it.

Plate

ecce xxviii. ig. 1.

These and similar considerations, prevailed with the patriotic society of Milan, to send to these places where scythes are used for reaping; and having procured a model from Silesia, they ordered one of a proper size to be made. It was first tried on corn, and afterwards on raillet; and notwithstanding the first was far from being made with accuracy, and although such an instrument had never before been made use of by the reaper, nearly half the usual time was found to be saved, and the wonted fatigue and labour were much diminished. The corn was cut without receiving any injurious shock, falling in an even and regular state, by which means it was afterwards bound up with ease in compact sheaves. These instruments are so simple in their construction, that a figure of one of them renders a description almost unnecessary. Fig. 1. represents the Silesian scythe tried by the society, the difference between which and the Austrian one we shall mention in our description. The Silesian scythe differs little from that commonly employed in mowing grass, except that the blade is rather smaller; to it four teeth of wood are added, parallel to the blade, fixed and secured in a proper manner, and designed to keep the corn together after it is cut; so that instead of its falling in a confused state, the reaper can lay it down in a regular and compact manner. The Austrian scythe is similar to the former, but the blade is larger; of course the wooden teeth, being five in number, are longer; the handle is also flatter, and rather crooked.

In the first, the handle a b (see fig. 1.) is four feet three inches in length; the blade bc is about two feet; the piece of wood in which the teeth are fixed, one foot ten inches and a half. In the second, the handle is four feet one inch; the blade, two feet eight inches; the piece in which the teeth are fixed, 11 inches.

The difference in the construction of these two scythes renders it necessary to use them in a different manner, which will be better acquired in practice than by precept. Such as are accustomed to the use of the common scythe will soon find out the most advantageous manner of using these new kinds of scythes, and of laying down the corn properly after it is cut.

It is necessary to observe, that, in mowing grass, the feet are held in a position nearly parallel to each other, whereas in reaping corn they should be kept on a line, the one behind the other, bringing the right foot forward, and drawing the left towards it. The reason is, that when grass is mowed it is left to fall where it is cut; but when corn is cut down, it is to be laid in a proper manner against that which is not yet cut, and which is at the reaper's left hand. Were the feet kept parallel to each other, the reaper would be under the necessity of extending and turning his body in a very

inconvenient manner.

These observations having been published, the society made farther experiments on the subject, by which they discovered, that when the stalks of corn are bent down by reason of extremely wet weather, the wooden teeth

of the scythes are apt to lay hold of some ears, to the Scythe, stalks of which the iron does not extend; and therefore Scythia. these not being cut below, are pulled so that the grain is scattered. This chiefly happens from the reapers not being accustomed to that kind of scythe, and therefore not knowing how to adapt it to particular existing eir

cumstances.

It occurred to an ingenious blacksmith, that, in order to remedy this inconvenience, a collector made of cloth should be added to the common scythe, as may be seen at fig. 2. where a b c is a common scythe, cdmlofne Fig. 2. is the gatherer, which at cde is composed of a thin plate of iron, having a hollow at its extremity for receiving the point of the blade. At ed are holes for sewing in the cloth, which is coarse, light, and of low price; it is also fixed to two thick iron wires, of which the upper one is continued to f, where it terminates in a hole in the handle; the other is fixed to the back of the blade. The manner of fixing this gatherer to the back of the scythe will be better understood by referring to fig. 3. which represents one of the irons, which, by Fig. 3. means of the screw, are fastened to the back of the scythe. These proceed from, and make part of the upright irons mn, lo, which serve to keep the gatherer extended.

This contrivance is both cheap and simple; but an attempt was made to render it more so, by substituting two iron hoops for the gatherer, which are shewn in fig. 2. by the dotted lines hg, ki, with a cross piece p, Fig. 2. which connects them. Experience has shewn, however, that the gatherer is in general preferable to these hoops, as it does not leave an ear of corn behind.

SCYTHIA, an ancient name for the northern parts of Asia, now known by the name of Tartary; also for some of the north-eastern parts of Europe.

This vast territory, which extends itself from the Ister or Danube, the boundary of the Celts, that is, from about the 25th to almost the 110th degree of east longitude, was divided into Scythia in Europe and Scythia in Asia, including, however, the two Sarmatias; or, as they are called by the Greeks, Sauromatias, now the Circassian Tartary, which lay between and severed the two Scythias from each other. Sauromatia was also distinguished into European and Asiatic; and was divided from the European Scythia by the river Don or Tanais, which falls into the Palus Meotis; and from the Asiatic by the Rha, now Volga, which empties itself into the Caspian sea

1. The Asiatic Scythia comprehended in general, Great Tartary, and Russia in Asia; and, in particular, the Scythia beyond or without Imaus, contained the regions of Bogdoi or Ostiacoi, and Tanguti. That within, or on this side Imaus, had Turkestan and Mongal, the Usbeck or Zagatai, Kalmuc and Nagaian Tartars; besides Siberia, the land of the Samoiedes and Nova Zembla. These three last not being so soon inhabited as the former, as may be reasonably supposed, were wholly unknown to the ancients; and the former were peopled by the Bactrians, Sogdians, Gandari, Sacks, and Massagetes. As for Sarmatia, it contained Albania, Iberia, and Colchis; which makes now the Circassian Tartary, and the province of Georgia.

2. Scythia in Europe reached (towards the southwest) to the Po and the Alps, by which it was divided from Celto-Gallia. It was bounded on the south by

the

Sea.

Scythia the Ister or Danube and the Euxine sea. Its northern U limits have been supposed to stretch to the spring-heads of the Boristhenes or Nieper, and the Rha or Volga, and so to that of the Tanais.-The ancients divided this country into Scythia Arimaspaa, which lay eastward, joining to Scythia in Asia; and Sarmatia Europeana on the west. In Scythia, properly so called, were the Arimaspai on the north; the Getæ or Dacians along the Danube on the south; and the Neuri between these two. So that it contained the European Russia or Muscovy, and the Lesser Crim Tartary eastward; and, on the west, Lithuania, Poland, part of Hungary, Transylvania, Walachia, Bulgaria, and Moldavia. Sarmatia is supposed to have reached northward to that part of Swedeland called Feningia, now Finland; in which they placed the Ocenes, Panoti, and Hippopodes. This part they divided from Northern Germany, now the west part of Sweden and Norway, by the Mare Sarmaticum or Scythicum, which they supposed ran up into the northern ocean, and, dividing Lapland into two parts, formed the western part of Sweden, with Norway, into one island, and Finland into another; supposing this also to be cut off from the continent by the gulf of that name.

I

What pro

Although the ancient Scythians were celebrated as a warlike people, yet their history is too uncertain and obscure to enable us to give any detail which would not prove equally tiresome and uninteresting to the reader. Mr Pinkerton, in a dissertation on their origin, endeavours to prove that they were the most ancient of nations; and he assigns for the place of their first habitation the country known by the name of Persia. From Persia, he thinks, they proceeded in numerous hordes westward, surrounded the Euxine, peopled Germany, Italy, Gaul, the countries bordering on the Baltic, with part of Britain and Ireland. That the Scythians were of Asiatic origin, cannot, we think, be questioned; and as Persia was peopled at a very early period, it may not improbably have been their parent country: but when our author contends that their empire had subsisted for more than 1500 years before Ninus the founder of the Assyrian monarchy, and that it extended from Egypt to the Ganges, and from the Persian gulf and Indian sea to the Caspian, we cannot help thinking that his prejudices against the Celts, and his desire to do honour to his favourite Goths, have made him advance a paradox inconsistent with the most authentic records of antiquity. His dissertation however is ingenious, and replete with a variety of curious learning.

SCYTHIAN Lamb, in Natural History. See Scythian LAMB.

SCYTHROPS, or CHANNEL-BILL, a genus of birds belonging to the order of Picæ. See ORNITHOLOGY,

N° 149.

SEA, in a strict sense, signifies a large portion of water almost surrounded by land, as the Baltic and Mediterranean seas; but it is frequently used for that vast body of water which encompasses the whole earth. What proportion the superficies of the sea bears to portion the that of the land, cannot easily be ascertained. Buffon has surface of supposed that the surface of our globe is equally divided the sea between land and water, and has accordingly calculated the superficies of the sea to be 85,490,506 square miles. But it is now well known that the ocean covers much more than the half of the earth's surface. Buffon be

bears to that of the land.

Sen.

2

the sea.

lieved the existence of a vast southern continent, which Captain Cook has shown to be visionary. It was this circumstance which misled him. According to the most accurate observations hitherto made, the surface of the sea is to the land as three to one; the ocean, therefore extends over 128,235,759 square miles, supposing the superficies of the whole globe to be 170,981,012 square miles. To ascertain the depth of the sea is still more difficult than its superficies, both on account of the Depth of numerous experiments which it would be necessary to make, and the want of proper instruments for that pur pose. Beyond a certain depth the sea has hitherto been found unfathomable; and though several methods have been contrived to obviate this difficulty, none of them has completely answered the purpose. We know in general that the depth of the sea increases gradually as we leave the shore; but if this continued beyond a certain distance, the depth in the middle of the ocean would be prodigions. Indeed the numerous islands everywhere scattered in the sea demonstrate the contrary, by showing us that the bottom of the water is unequal like the land, and that so far from uniformly sinking, it sometimes rises into lofty mountains. If the depth of the sea be in proportion to the elevation of the land, as has generally been supposed, its greatest depth will not exceed five or six miles, for there is no mountain six miles perpendicular above the level of the sea. The sea has never been actually sounded to a greater depth than a mile and 66 feet; every thing beyond that therefore rests entirely upon conjecture and analogical reasoning, which ought never to be admitted to determine a single point that can be ascertained by experiment, because, when admitted, they have too often led to false conclusions. Along the coasts, where the depth of the sea is in general well known, it has always been found proportioned to the height of the shore: when the coast is high and mountainous, the sea that washes it is deep; when, on the contrary, the coast is low, the water is shallow. Whether this analogy holds at a distance from the shore, experiments alone can determine.

contains

To calculate the quantity of water contained in the Quantity sea, while its depth is unknown, is impossible. But if of water we suppose with Buffon that its medium depth is the which it fourth part of a mile, the ocean, if its superficies be 128,235,759 square miles, will contain 32,058,939-75 cubic miles of water.

art. 10.

Let us now endeavour to compute the quantity of water which is constantly discharged into the sea. For this purpose let us take a river whose velocity and quantity of water is known, the Po, for instance, which ac- Buffon's cording to Riccioli is 1000 feet (or 100 perches of Theory of Bologna) broad, 10 feet deep, and runs at the rate of the Earth, four miles in an hour; consequently that river discharges into the sea 200,000 cubic perches of water in an hour, or 4,800,000 in a day. A cubic mile contains 125,000,000 cubic perches; the Po therefore will take 26 days to discharge a cubic mile of water into the sea. Let us now suppose, what is perhaps not very far from the truth, that the quantity of water which the sea receives from the rivers in any country is proportioned to the extent of that country. The Po from its origin to its mouth traverses a country 380 miles long, and the rivers which fall into it on every side rise from sources about sixty miles distant from it.

The