inches long, befides a tail of 34. This fpecies i= habit Surinam.

Catefby, or the Striated Weafel of Pennant, is blackish, with 5 parallel white ftripes, from the head along the back and fides, to the tail; inhabits N. America, is of the fize of a cat, but longer in the body; the head is round, with a long fnout, and 3 rows of whiskers; the hind feet are long, and reft on the heel; all the feet have 5 toes; the fore feet have long claws; the fore teeth are all parallel and equal. This fpecies dig holes in the earth; fleep all day, and roam for prey in the night, and feed on worms, infects, poultry, eggs, and flesh. When attacked by dogs, they brittle up the hair on their back; and when irritated, defend themselves by a fetid vapour.

(2.) WEASEL, BROWNISH, Muftela fubfusca, of Brown, of Jamaica; the Cape Fitchet, or Viverra Capenfis, of Schreber, and the Ratel Weafel of Pennant; the far is long and black, with a grey or brownish black, edged with a white line; is 2 feet long, befides a tail of 8 inches. They inhabit Guinea and the Cape, defend themselves by their fetor, and are fond of wild honey.

3. WEASEL, FOUR-TOED, of Miller and Pennant; Viverra tetradactyla, or the Surikate of Schreber; has only 4 toes on each foot; a nofe long and flexible; is 12 inches long, befides a tail of 8; the muzzle is fharp, the upper jaw longeft, the tip black; with black whifkers; ears black, fmall, rounded, and Aat: the back broad and rounded; belly broad and flat; legs fhort, feet fmall, with long claws before, and thort behind. They inhabit Java, and S. Africa; grunt; are much in motion; often fit upright, the fore paws hanging down; when pleased, make a noife like a fmall rattle feed on raw flesh, chickens, eggs, and fifh; they burrow in the ground, but are easily tamed.

4. WEASEL, GREY, or Grifon, of Pennant and Buffon, and Schreber: Viverra Vittata of Kerr and Gmelin; or the YAGUANE of Falkner; has a white fillet from the fhoulders, across the fore head; the head is very large; ears femicircular and fhort; eyes large; 6 cutting teeth in each jaw; 5 toes on all the feet, with yellowish claws; the fur is brown, with white tips, appearing grey; the head and neck bright grey; the muzzle, un. der parte, legs and tail, black; the body is 7

5. WEASEL, MEXICAN, of Pennant; Viverr. Prebenfilis, or Kinkajou, of Buffon; is 24 feet lors with a tail i foot 3; the fur olive, grey, an brown; the tail prehenfile; the nofe dufky tongue long, ears fhort and rounded; eyes fmail throat and legs, a lively yellow; the belly yellow ith white; the palms of the paws are naked, and of a vermilion colour; with toes each, and white hooked claws. They inhabit Mexico; ar gentle and lively, fit up like fquirrels, are fond e fugar, fruits, and plants, but fuck the blood poultry, without eating the flesh.

E

6. WEASEL, SPANISH, of Briffot; Viverr Genetta, or Spanish Genet of Schreber; the Gene of Pennant; has a long tail, with parti-coloure rings; the body covered with blackish spots. resembles the ZIBET, (See VIVERRA, N° 3.) bu is (maller; being 17 inches long, befides a tail o 12, black, but annulated with white rings. frequent rivulets in Afia, Spain, the S. of France and about Conftantinople; they are gentle, eafil tamed, playful, and catch mice.

The

7. WEASEL, STIFLING, of Pennant, Viverra Quasje of Gmelin; or the YZQUUIEPATL, O Little Fox of Seba; inhabits Surinam, but is al ready pretty fully described under VIVERRA, N° 2 8. WEASEL, VARIEGATED, of Briffot, or th ICHNEUMON. (See VIVERRA, N° 1.) Mr Ker defcribes other 3 fpecies of the Ichneumon, viz the Indian, Cafrarian, and African; but none o them differ greatly from the one already de fcribed.

9. WEASEL, YELLOW, of Pennant, Viverr. Caudivolvula of Schreber; the Potto of Buffon is of a mixed yellow and black colour, and has prehenfile tail of 17 inches long; the body alon is 19. The head is broad and flat; the cheek fwollen; nofe fhort and dusky; eyes fmail; ear fhort, broad, and flapping; tongue long; fu fhort, foft, and gloffy; the legs thick and fhort with 5 toes each foot, and large flesh-coloured claivs, hooked. Yet it is mild and playful, and fufpends itfelf by the tail like the SAPAJOUS (See SIMIA, N° V. 43-53.) They inhabit the mountains of Jamaica.

sphere with regard to all other meteors. See METEOROLOGY.

INTRODUCTION.

We infert this article in the form of a science, not only on account of its scientific nature, and neceffary connection with various fciences, but also because a divifion into fections, in the alphabetical order, would unavoidably interrupt the connection that ought to be preferved in all its parts, and render confused what we wish to make as perfpicuous and intelligible as possible.

The phenomena of the weather must have at all times attracted much of the attention of mankind, because their fubfiftence and their comfort in a great measure depended upon them. It was not till the 17th century, however, that any confider able progrefs was made in investigating the laws of meteorology. How defirous foever the ancients might have been to acquire an accurate know ledge of this science, their want of proper inftru. ments entirely precluded them from cultivating it. By the discovery of the BAROMETER and THERMOMETER in the 17th century, and the invention of accurate ELECTROMETERS and HYGROMETERS in the 18th, this defect is now pretty well fupplied; and philofophers are enabled to make meteorological obfervations with ease and accuracy. Accordingly a very great number of fuch obfervations have been collected, which have been arranged and examined from time to time by ingenious men, and confequences deduced from them, on which feveral different theories of the weather have been built. But meteorology is a science so exceedingly difficult, that, notwithstanding the united exertions of some of the first philofophers of the age, the phenomena of the weather are ftill very far from being completely understood; nor can we expect to fee the veil removed, till accurate tables of observations have been obtained from every part of the world, till the atmosphere has been more completely analyfed, and the chemical changes which take place in it ascertained. From the meteorological facts, however, which are already known, we shall give our readers the best account of the weather we can; and fball treat of the different phenomena in the following order: heat and cold, wind, rain, thunder, alterations in the gravity of the atmoSphere.

SECT. I. Of HEAT and COLD.

I. THOUGH the temperature of the atmosphere in fummer and in winter varies materially in every part of the world; though in the fame feafon the temperature of almost every day, and even every hour, differs from that which precedes and follows it; though the heat varies continually in the moft irregular and feemingly capricious mannerftill there is a certain mean temperature in every climate, which the atmosphere has always a tendency to obferve, and which it neither exceeds nor comes fhort of, beyond a certain number of degrees. What this temperature is, may be known by taking the mean of tables of observations kept for a number of years; and our knowledge of it must be the more accurate the greater the number of observations is,

The greatest mean annual temperature is at the equator (or at least a degree or two on the north fide of it); and it diminishes gradually towards the poles, where it is least. This diminution takes place in arithmetical progreffion, or, to speak more properly, the annual temperature of all the latitudes are arithmetical means between the mean annual temperature of the equator and the pole. This was first discovered by Mr MAYER; and, by means of an equation which he founded on it, but rendered confiderably plainer and fimpler, Mr KIRWAN has calculated the mean annual temperature of every degree of latitude between the equator and the pole. He proceeded on the following principle. Let the mean annual heat at the equator be m and at the pole m―n; put ❤ for any other latitude; the mean annual temperature of that latitude will be m-n X fin. 2. If therefore the temperature of any two latitudes be known, the value of m and n may be found. Now the temperature of N. lat. 40° has been found by the beft obfervations to be 62.1°, and that of lat. 50°, 52'9°. The fquare of the fine of 40° is nearly 0419, and the fquare of the fine of 50° is nearly 0'586. Therefore

m-041n62°1 and

m-058n=52'9: therefore

621+0°41 n=52'9 +0°58 n, as each of them, from the two firft equations, is equal to m. From this laft equation the value of n is found to be 53 nearly; and m is nearly equal to 84. The mean temperature of the equator therefore is 84°, and that of the pole 31o. To find the mean temperature for every other latitude, we have only to find 88 arithmetical means between 84 and 31. In this manner Mr Kirwan calculated the following table.

TABLE of the MEAN ANNUAL TEMPERATURE of the STANDARD Situation, in every LATI

TUDE.

But this table gives only the temperature of the atmosphere of the ocean. It was calculated for that part of the Atlantic ocean which lies between 80° of N. and 45° of S. lat. and extends W. as far as the GULF STREAM, and to within a few leagues of the coaft of America; and for all that part of the Pacific ocean reaching from lat. 45° N. to lat. 40° S. from 20° to 275° lon. E. of London. This part of the ocean Mr Kirwan calls the STANDARD; the reft of the ocean is fubject to anomalies which will be afterwards mentioned.

The mean monthly temperature of the standard ocean has also been calculated by Mr Kirwan. The principles on which he went were thefe: The mean temperature of April feems to approach very nearly to the mean annual temperature; and as far as beat depends on the action of the folar

rays, the mean heat of every month is as the mean altitude of the fun, or rather as the fine of the fun's altitude. The mean heat of April, therefore, and the fine of the fun's altitude being given, the mean heat of May is found in this manner: As the fine of the fun's mean altitude in April is to the mean heat of April, so is the fine of the fun's mean altitude in May to the mean heat of May. In the fame manner the mean heats of June, July, and Auguft, are found; but the rule would give the temperature of the fucceeding months too low, because it does not take in the heat derived from the earth, which poffeffes a degree of heat nearly equal to the mean annual temperature. The real temperature of these months therefore must be looked upon as an arithmetical mean between the aftronomical and terrestrial heats. Thus in latitude 51o, the aftronomical heat of September is 44'6°, and the mean annual heat is 52'4°; therefore the real heat of this month should be 446 + 44'6+52'4 =48'5. Kirwan, however, after going through a tedious calculation, found the refults to agree fo ill with obfervations, that he drew up the following table, partly from principles and partly by studying a variety of fea journals.

2

Mr

28.5 29

30 31 32

30°5 \31° 31°