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the jar was covered with thick cotton, the quantity of ice melted was increased : but even when the jar was plunged in a freezing mixture, more ice was melted by water of the heat of 41° than by boiling water. Very little difference occurred when the jar was in the temperature of 32° or 61°.

• All these appearances might, I think, be accounted for in a fatisfactory manner on the principles we have assumed respecting the manner in which heat is propagated in liquids ; but without engaging ourselves at present too far in these abstruse speculations, let us take a retrospective view of all our experiments, and see what general refults may with certainty be drawn from them.......

Ice melted

in 30 minutes

Grains With boiling-hot water (ex.)

periments No. 39, 40, }| 558 * In the experiments in which ! With water at the tempe

and 41) the part of the jar which

rature of 619 (experi-(1 616 was occupied by the wa

ments No. 53 and No. ter was exposed uncovered to the air at the tem

54)

With water at the tem-) perature of 61°

perature of 410 (experi-(

ments No. 42 and No.() i 43)

( With boiling- hot water (ex-) In the experiments in which

periments No. 45, 46, | 399

| 47, 48, and 49) the part of the jar which

With water at the tem-) was occupied by the water was surrounded by

perature of 61° (experi.

El 661 pounded ice and water,

ments No. 51 and No. and consequently was at

With water at the temthe temperature of 32°

perature of 41° (experi. | 542

ment No. 50) : ST • From the results of all these experiments we may certainly venture to conclude that boiling-hot water is not capable of melting more ice when standing on its surface, than an equal quantity of water at the temperature of 41°, or when it is only nine degrees above the temperature of freezing!

• This fa&t will, I flatter myself, be considered as affording the most unquestionable proof that could well be imagined, that water is a perfect non-conductor of heat, and that heat is propagated in it only in consequence of the motions which the heat occasions in the ine sulated and solitary particles of that Auid * P. 277. · We have followed the count in these experiments with unusual attention, because we deem them very important. We may be more concise in speaking of his application. The law of condensation of water, in cooling, is productive of many great advantages. In cooling 22 degrees of Fahrenheit, the condensation is ninety times greater when the water is boiling than at the mean temperature of England. The consequence is, that fresh water must freeze slowly; and, when the surface is frozen, the water below, brought from the mean tempera. ture of the earth to 40°, will ascend and prevent the increase of ice beyond a certain thickness, while on a thaw, it will diminish the under surface as fast as the increased heat of the air corrodes the upper. Ice then, and snow in a greater degree, keep tlie water at a moderate temperature, even in the coldest weather of the molt ungenial climates ; and the ice is prevented from acquiring a thickness which no summer's sun could diffolve. The salt water, however, is not influenced by any funilar law; but its depth prevents it from attaining so great a degree of cold, and its saltness from being affected at the temperature of 32°. Its flux and reflux, and its currents on the surface, the balance of which is reciprocally supplied by suitable under currents, contribute to equalise the temperature. If, as we had occasion to remark, the currents of the ocean tend from the equator northward, we shall see additional reasons for assigning this office of equalising temperature to the sea. We may, on probable grounds, Tuppose that the course of the currents is not from the equator to the south pole, and we can explain the difference by La Place's demonstration, that the hemispheroids, of whichi this planet consists, are not equal; but we see the effe Et in the increased intensity of the cold in the southern hemisphere at equal latitudes.

• But the ocean is not more useful in moderating the extreme cold of the polar regions, than it is in tempering the excessive heats of the torrid zone ;- and what is very remarkable, che fitness of the sea water to serve this last important purpose is owing to the very same cause which renders it fo peculiarly well adapted for communicating heat to the cold atmosphere in high latitudes, namely, to the salt which it holds in solution.

5* The insight which this discovery gives us in regard to the nature of the mechanical process wbich takes place in chemical solutions is too evident to require ilustration ;-and it appears to me that it will enable us to account in a satisfactory mauner for all the various phænomena of chemical affinities and vegetation. Perhaps all the motions among inanimate bodies on the surface of the globe may be traced to the same cause, amely, to the non-conductings power of fluids with regard to heat,'

.. .... 19

• As the condensation of salt water with cold continues to go on even long after it has been cooled to the temperature at which fretli water freezes, those particles at the surface which are cooled by an immediate contact with the cold wind, must descend, and take their places at the bottom of the sea, where they must remain, till, by ac. quiring an additional quantity of heat, their specific gravity is again diminished. But this hieat they never can regain in the polar regious, for innumerable experiments have proved, beyond all possibility of doubt, that there is no principle of heat in the interior parts of the globe, which, by exhaling through the bottom of the ocean, could communicate heat to the water which rests upon it.

" It has been found that the temperature of the earth at great depth under the surface is different in different latitudes, and there is no doubt but this is also the case with respect to the temperature at the bottom of the sea, in as far as it is not influenced by the currents which flow over it; and this proves to a demonstration that the heat which we find to exist, without any senĞble change during fumnier and winter, at great depths, is owing to the action of the fun, and not to central fires, as some have too hastily concluded.

• But if the water of the ocean, which, on being deprived of a great part of its heat by cold winds, descends to the bottom of the fea, cannot be warmed where it defcends, as its specific gravity is greater than that of water at the same depth in warmer latitudes, it will iinmediately begin to spread on the bottom of the sea, and to flow towards the equator, and this inuft neceflarily produce a current at the surface in an oppofite direction; and there are the most in. dubitable proofs of the existence of both these currents.

The proof of the existence of one of them would indeed have been quite sufficient to have proved the existence of both, for one of them could not poflibly exist without the other : but there are few veral direct proofs of the existence of each of them.

• What has been called the gulf stream, in the Atlantic Ocean, is no other than one of these currents that at the surface which moves from the equator towards the north pole, modified by the trade winds, and by the form of the continent of North America; and the progress of the lower current may be considered as proved direétly by the cold which has been found to exist in the sea at great depths in warm latitudes;<a degree of temperature much below the intan annual temperature of the earth in the latitudes where it has been found, and which of course must have been brought from colder latitudes.

The mean annual teniperature in the latitude of 6;" has been determined by Mr. Kirwan, in his excellent treatise on the temperature of different latitudes, to be 39°; but lord Mulgrave found on ihe 20th of Jone, when the temperature of the air was 48{°, that the teinperature of the sea at the depth of 4680 feet was fix degrees below freezing, or 260 of Fahrenheit's thermometer.

• On the zilit of August, in the latitude of 69°, where the annual

temperature is about 38°, the temperature of the sea at the depth of 4038 feet was 32°; the temperature of the atmosphere (and probably that of the water at the surface of the lea) being at the same time at 591

• But a still more striking, and I might, I believe, say an incon-, trovertible proof of the existence of currents of cold water at the bottom of the sea, setting from the poles towards the equator, is the very remarkable difference that has been found to sublist between the temperature of the sea at the surface and at great depth, at the tropic,--though the temperature of the atmosphere there is so conItant that the greatest changes produced in it by the seasons seldom amounts to more than five or fix degrees; yet the difference between the heat of the water at the surface of the sea, and that of the depth of 3600 feet, has been found to amount to no less than 31 degrees; the temperature above or at the surface being 84', and at the given depth below no more than 53o.

" It appears to me to be extremely difficult, if not quite impofli. ble, to account for this degree of cold at the bottom of the sea 'in the torrid zone, on any other supposition than that of cold currents from the poles; and the utility of these'currents in tempering the exceflive heats of those climates is too evident to require any ile luftration.' P. 309.

We can cheerfully join in our author's conclusion, that all is wisely and happily contrived for the best : though we see through a glass darkly, we see enough to admire and adore the benevolence and wifdom of the supreme contriver of all...

The eighth essay contains the substance of the two papers published in the Philosophical Transactions, already quoted, and the ninth is on the source of heat excited by friction,' published in the volume of Philosophical Transactions for 1798, and noticed by us in our XXIVth volume, N, A. p. 37. Our auchor's future labours, some of which have recently ap. peared, we shall receive with pleasure and gratitude.

An Account of an Embally to the Kingdom of Ava. Canti

nued from Vol. XXIX, p. 371, New Arr.). .. .

UMMERAPOOR A, the present capital of the united kingdoms of Ava, Arracan, and Pegu, was founded by Minderagee Praw, a succeffor of Alompra, either from.vanity, or the superstitions inspired by judicial astrology, a study to which he was much addicted. Úmmera poora is situated about four miles north-east of Ava: - In this fpot, a deep anıt extensive lake is formed by the influx of the river, through' 'a natrow channel, during the sumnıner monsoon. It foon expands, and displays a body of water a mile and half broad, and leven, or Crit. Rev. VOL. XXX. Orober, 180o. J.

M en eight miles long. Its direction is, at first, northerly, nearly parallel with the river, but it afterwards' curves to the southeaft, wliile its stream gradually terminates in a morass, thus forming a dry liealthy peninsula. This spot was arid and parched at the time of our author's arrival, though little above the level of the lake; and the usual embankments, for the plantations of rice,' were, from the uncommon drought, use. less: the formerly fertile grounds were an unproductive waste:

* As soon as my visitors took their leave, I made a survey of our new habitation; it was a spacious house of one story, raised from the ground somewhat more tban two feet, and better covered than Birman houses usually are;. it covoited of two good sized rooms, and a large virando, or balcony; the partitions and walls were made of cane mats, with latticed windows in the Gdes : the tape of the roof was such as distinguishes the houses of nobles: it was altogether a comfortable habitation, and well adapted to the climate, Mr. Wood had a smaller house erected behind mine, and parallel to it, and Dr. Buchanan another at right angles. Small separate huts were constructed for the guard, and for our attendants; the whole was surrounded by a strong bainboo paling, which inclosed a court yard. There were two entrances by gates, one in front of my house,, the other backwards ; at each of these, on the outside of the paling, was a fhed, in which a Birman guard was poited to protect us from thieves, keep off the populace, and probably to watch and report our movements..'

"On tite kirts of the same' grove, in a line with our dwelling, funilar houfes 'mere erected for three Chinese deputies, who had ar. rived at Ummerapoora about two months before us: these perfonages were represented as composing a royal'misfion from the imperial city of Pekin, but circiimstances early led me to suspect that their real character did not rise higher than that of a provincial deperation from Manchegee, or Yunan, the south-west province of China, which borders on the kingdoni of Ava, a conjecture that was afterwards confirmed. They had accompanied the governor of Bamoo, wbich is the frontier province, to the capital; and I underitood that their business was to adjust some mercantile concerns re. lating to the jee, or mari, where the commodities of the two empires are brought and birtered. It was not at all improbable that the mission had been fan&tioned by the authority of the emperor of China, especially as the principal member of it was a native of Pekin, and had lately come from thence: but the false pride of the Birman court suggested the puerile * expedient of representing it to us as an imperial embally, a distinction to which, I was privately

"The Chinese seem to have been actuated by a policy equally absurd, when they intormed fir George Staunton, at the time of the formal introduction of lord Macartney, that " emhaffacors from Pegue" were present; and Bhat «Siam, Ava, and Pogüe, were tr bucary to China:" such unworthy dereptions not being expced, could hurdly be guarded against. The courts of

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