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was expelled from finery cinder by heat, I went through fimilar procefies with this fubftance and mafficot, from which all air had been previously expelled; and after reviving both of them in inflammable air, I found the refults, in all refpects, the very fame. The refiduums of the inflammable air were equally free from fixed air; and when they were fired with equal quantities of dephlogisticated air, the diminutions of bulk were very nearly the fame, lefs than when the original inflammable air was ufed, becaufe all the impurities in the whole quantity were retained in a small refiduum, the metals having imbibed nothing but pure phlogiston. Alfo the inflammable air had been long confined by water, in confequence of which it is always altered more or lefs.'
We may perhaps add that, in the experiments with the electrical machine, in igniting the two kinds of air, the force feems greatest on the lower part of the tube, which dilates and foon burfts; this Dr. Priestley explains, by fuppofing that the spark expands the air in the upper part, and, of course, condenfes it in the lower, where confequently the heat and the force appears to be greatest.
Art. III. Obfervations on the Clafs of Animals, called by Linnæus Amphibia; particularly on the Means of distinguishing those Serpents which are venomous, from those which are not fo. By E. W. Gray, M. D. P. R. S.-In the clafs of amphibia, Mr. Gray confiders, we think with reafon, Linnæus as unufually hafty, and peculiarly unfortunate. The amphibia nantes are not furnished with lungs; and, on that account, foreign naturalists, as we have lately obferved in that department of our work, have removed the cartilaginous fishes to the pifces." A fingle ventricle is also not the most common ftructure, for the hearts of the amphibia are ufually double, with an aperture between the ventricles, analogous to the foramen ovale of the foetus. The diftinction is, however, as Mr. Gray acknowledges, pretty complete, by the character of having cold red blood, and being furnished with lungs.
The diftinction between the poisonous genera and the others, has not yet been properly pointed out; and we fufpect the terrors of ignorant perfons have in fome refpects influenced naturalifts. In one or two inftances our author feems to have been mifled by these impreffions. His diftinctions are taken from the shape of the head, of the tail, and the fituation of the teeth. A broad head covered with small scales, though not a certain criterion, he thinks, with a few exceptions, is a general character of venomous ferpents. A tail under, one-fifth of the length is another, though not without exceptions; but a tail, longer in proportion, is a pretty certain mark that the animal is innocent. A thin acute tail is not, on the whole, peculiar to Ffz
the venomous clafs; but a thick obtufe one is only found among the innoxious ones: carinated fcales are in fome measure a mark of the poifonous tribe. The fangs of the poisonous fort are not always, or perhaps effentially, moveable: their fize is various, and they are generally fituated in the anterior and exterior part of the upper jaw, not connected with a row of teeth all round. Venomous ferpents have only two rows of teeth, and the innoxious ones have four. The number of venomous ferpents is perhaps about one in fix.
Art. IV. Obfervations on the Drynefs of the Year 1788. In a Letter from the Rev. Mr. B. Hutchinfon, to Sir J. Banks, Bart. P. R. S.-At Kimbolton (in Huntingdonshire) the mean quantity of rain for feven years was 25 inches, but in 1788 it was only 14.5. We perceive, from the journal at the end, that in London it was only 14.9 nearly; and we should not indeed expect a very great difference at a distance fo inconfiderable. The last year was confeffedly a fruitful one; and our author endeavours to explain it by fhowing, that the rain fell at the time when it may be supposed to have been moft serviceable to the corn and the fruits.
Art. V. On the Method of determining from the real Probabilities of Life, the Value of a contingent Reverfion in which Three Lives are involved in the Survivorship. By Mr. William Morgan; communicated by the Rev. R. Price, D. D. F. R. S. This is the fupplement of a former paper on this fubject. Mr. Morgan informs us, that on purfuing the fubject farther, he finds that, as it is never fafe, fo it can never be necefary to have recourfe to the expectations of life in any case; and that the folution of problems, which include three lives, is far from being fo formidable as it appears. His fupplement chiefly confiits of the folution of the following problem:
Suppofing the ages of A, B, and C to be given, to deter mine, from any table of obfervations, the value of the fum S, payable on the contingency of C's furviving B, provided the life of A fhall be then extinct.'
Simpson's value of 100l. payable on the contingent of this problem appears, from this folution, to be very erroneous.
Art. VI. Refult of Calculations of the Obfervations made at various Places of the Eclipfe of the Sun, which happened on June 3, 1788. By the Rev. Jofeph Piazzi, C. R. Profeffor of Aftronomy in the Univerfity of Palermo; communicated by N. Mafkelyne, D. D. F. R. S. and Aftronomer Royal. - The differences of longitude, in various places, deduced from thefe obfervations are very important, and we may be allowed to extract the table fo far as relates to this fubject:
Greenwich, Dr. Mafkelyne,
Milan, Meff, de Cefaris and Reggio,
Art. VII. An Account of a bituminous Lake or Plain in the Island of Trinidad. By Mr. Alexander Anderson; communicated by Sir Jofeph Banks, Bart. P. R. S.-The island Trinidad is between Tobago and the Spanish Main. The lake confifts of petroleum of an uncertain depth, on a spot pretty certainly volcanic. It hardens and forms by retraction, areolæ not unlike those on the back of a turtle: in fact, it is a tarred spot, whofe little hollows are occafionally filled with water; and, where the heat is concentrated by the woods, the tar is liquid. Hot fprings abound in the neighbourhood, 22 or 24 degrees hotter than the atmosphere, probably about 100 degrees of Fahrenheit. The island is covered with argillaceous earth, and the mountains are compofed of fchiftus argillaceus, and talcum lythomargo. Our author's theory of the formation of the island is only a theory of its increase, from the effects of the currents into the gulf of Paria from the coafts of Brazil and Andalufia, and the confequent eddies: it is of much lefs value than his obfervations.
VIII. An Account of a particular Change of Structure in the human Ovarium. By M. Baillie, M. D.; communicated by J. Hunter, Efq. F. R. S. - Dr. Baillie, in this paper, as well as in his former one, attempts to fay fomething new; but it is to us unintelligible. It is fufficient to remark, that the hair and teeth found in this cafe in the ovarium, were wholly and decidedly independent of impregnation, but to fay that, in given circumstances, the ovarium may have an aptitude of tak
ing on a procefs, fomewhat fimilar to generation,' may appear to be philofophical, though they are in reality, words without meaning. We might philofophize nonfenfically in our turn, and fpeak of the vegetable nature of hair and teeth,' but we would not trifle with our readers; and we fhall confefs, that the cafe is wholly unintelligible, unlefs we fuppofe a confufion of two fœtufes, where the most incorruptible parts remain, and from their vegetative nature, increase to a magnitude which has attracted attention. This, though the more probable hypothefis, we cannot recommend as deferving a moment's notice; it has not, however, detained us long.
Art. IX. Some Account of the Vegetable and Mineral Productions of Boutan and Thibet. By Mr. Robert Saunders, Surgeon at Boglepoor in Bengal; communicated by Sir Joseph Banks, Bart. P. R. S.-This journey is in many respects curious; and has afforded us information and entertainment The country from Bahar to Buxaduar is flat, marfhy, and unwholfome; but at Buxaduar, lat. 26° 3, the thermometer falls almoft to our fummer heat, and the Bengal plants require nurfing it was never above 82° or below 73°. The rains were inceffant, and this part of the country appears to be unhealthy. The country contains quartz refembling marble, fparry flint, and granite; and, in the progress northward, Mr. Saunders met with European plants and European heats. From Chouka to Panuka there is much lime-ftone, which the natives know not the use of. At Chepta, about the latter end of May, the neighbouring mountain Lomyla was covered with fnow, and the thermometer was at 57°. Chalk and lime-stone again occur, with chalybeate fprings, in their way to Taffefudon, the capital of Boutan, in lat. 27° 43', from major Rennel's map. This country is, in general, fruitful, and feems to be filled with European plants, for the neighbouring mountains are almoft conftantly covered with fnow. They have two crops annually; the one of wheat, the other, fowed in the rainy feafon, of rice the minerals are chiefly iron, with a very little copper:
Here (on the mountains near the fource of the Pachu) we quit the boundary of Boutan, and enter the territory of Thibet, where nature has drawn the line ftill more ftrongly, and affords, perhaps, the most extraordinary contraft that takes place on the face of the earth. From this eminence are to be feen the mountains of Boutan, covered with trees, shrubs, and verdure to their tops, and on the fouth fide of this mountain, to within a few icet of the ground on which we tread. Cn the north fide the eye takes in an extenfive range of hills
and plains, but not a tree, fhrub, or fcarce a tuft of grass to be feen. Thus, in the courfe of lefs than a mile, we bid adieu to a moft fertile foil, covered with perpetual verdure, and enter a country where the foil and climate feem inimical to the production of every vegetable. The change in the temperature of the air is equally obvious and rapid. The thermometer in the forenoon 34, with froft and fnow in the night-time. Our prefent obfervations on the caufe of this change confirmed us in a former opinion, and incontestably prove, that we are not to look for that difference of climate from the fituation of the ground as more or lefs above the general level of the earth. In attending to this caufe of heat or cold, we thuft not allow ourfelves to be deceived by a comparison with that which is immediately in view. We ought to take in a greater range of country, and where the road is near the banks of a river, we cannot well err in forming a judgement of the inclination of the ground. Punukha and Wandepore, both to the northward of Taflefudon, are quite in a Bengal climate. The thermometer at the first of thefe places, in the months of July and January, was within two degrees of what it had been at Rungpore for the fame periods. They feem in more expofed fituations than Taffefudon; and, were we to draw a comparison of their heights from the furrounding ground, I fhould fay they were above its level. The road, however, proves the reverse. From Punukha to Taffefudon we had a continued and fleep afcent for fix hours and a half, with a very inconfiderable defcent on the Taffefudon fide. From the fouth fide of the mountain dividing Boutan from Thibet, the fprings and rivulets are tumbling down in cafcades and torrents, and have been traced by us near to the foot of the hills, where they empty themfelves to the eastward of Buxaduar. On the north fide they glide fimoothly along, and by paffing to the northward as far as Tifhoolumboo, prove a defcent on that fide, which the eye could not detect. This part of the country, being the most elevated, is at all times the coldeft: and the fnowy mountains, from their heights and bearings, notwithstanding the distance, are certainly thofe feen from Purnea.
The foil on the Thibet fide of the mountain is fandy, with much gravel and many loose ftones.'
In thefe higher grounds lakes containing alum and the mineral alkali were not uncommon : the wind from the fouth-eaft blowing over the defert just mentioned, is cold, piercing, and almost equal to the harmattan in drynefs. When they proceed farther into the dominions of the Delai Lama, they find the sky ferene, and the country fertile; the minerals rich, plentiful, and frequent, particularly gold; lead, containing much filver; and a very rich cinnabar. Rock-falt and borax are known to be productions