any length of time, contains a mixture of carbonic and azotic gafes, the laft of which would form nitric acid with oxygen. Hence it is eafy to account for the adventitious portion of acid. With regard to the quantity of water diffolved in air, it is found to be extremely, fmall. Carbonic gas has indeed a stronger attraction, and retains a large portion in folution.

Art. XII. Some Obfervations on the Irritability of Vegetables. By James Edward Smith, M. D. F. R. S. Nature afcends through her productions by minute and infenfible gradations. A ftriking analogy in the ftructure and phyfiology subfifts between animals and vegetables. Every plant possesses, in fome degree, that principle of irritability, which was once conceived to be the characteristic of animal life. The delicate fenfibility of the mimofa, fenfitiva and pudica has long been admired. The dionaa mufcipula, from Carolina, manifefts this quality in a more remarkable manner; it grafps the infects that alight upon it, and transfixes them with its prickles. In the barberry, berberis communis, the ftamina are extremely irritable. Dr. Smith has examined this fubject with attention, and finds that this quality is confined to that fide of the filament next the germen. Upon touching that part with a fine briftle, feather, &c. the ftamina fpring forwards with great vigour from the petals, under which they were sheltered, to the ftigma.

Dr. Smith, like many of the difciples of Linnæus, is fond to indulge in the fearch of final caufes. But this is not the province of the philofopher. He then leaves the field of reason to foar in the aerial regions of fancy. How many inftances does the hiftory of philofophy record of imagined defign, which were afterwards exploded? and how much did these contribute to retard the progrefs of discovery?

Art. XIII. An Account of Experiments made by Mr. John M'Nab, at Albany Fort, Hudfon's Bay, relative to the freezing of Nitrous and Vitriolic Acids. By Henry Cavendish, Efq. F. R.S. and A. S. It would be tedious and uninterefting to give a detail of these experiments. We fhall content ourselves with an abftract of the refult. It appears that spirit of nitre fuffers not only an aqueous congelation, in which the watery part chiefly freezes, but also a spirituous congelation, in which the acid itself freezes. When the ftrength of the acid is fuch as not to diffolve so much as .243 of its weight of marble, it is liable to the aqueous congelation folely; and this congelation takes place at 44° below the freezing point, or at a higher temperature, according as the ftrength of the acid is diminished. When the strength of the acid is .418, it undergoes the fpirituous congelation at the leaft degree of cold, which is 2° below the freezing point; and, if the acid be either ftronger or weaker,

it requires a more intenfe 'cold to bring on the congelation. The oil of vitriol is more irregular in its congelations; it has two degrees of ftrength' at which the heats of its freezing points are minima. At the ftrength of .977, its freezing point is +1°; at .918, —26°; at .846, +42°; at .758, -45°.

The first part of this volume of the Royal Tranfactions concludes with a meteorological journal for 1787, kept in the apartments of the Society, by order of the prefident and council. From this it appears that the medium temperature without was 51°, the average height of the mercury in the barometer 29,8 inches, and the quantity of rain fallen 17 inches.

ART. V. Medical Inquiries and Obfervations. To which is added an Appendix, containing Obfervations on the Duties of a Physician, and the Methods of improving Medicine. By Benjamin Rufh, M.D. Profeffor of Chemistry in the University of Pennsylvania. The Second Edition. 8vo. 4s. fewed. Philadelphia, printed: Dilly, London. 1789.

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DR.

R. Rufh poffeffes fome ingenuity, and, unlike the generality of his countrymen, writes with confiderable correctnefs and elegance. His genius is verfatile and fpecious; his ideas are confused, unconnected, and often extravagant. His language fometimes grovels with vulgarifms, but oftener it fwells with falfe eloquence. The firft effay in this collection, read before the American Philofophical Society at Philadelphia in 1774, is an inquiry into the natural hiftory of medicine among the Indians. The children are plunged every day in cold water, and are fuckled till they are near two years old. In order to facilitate their being moved from place to place, and at the fame time to preserve their fhape, they are tied to a board, when they lie on their backs for fix, ten, or eighteen months. The Indians ufe a diet partly animal and partly vegetable; their animals are wild, and therefore eafy of digeftion. They have no fet time for eating, and, after whole days spent in the chace or in war, they often commit great exceffes. They frequently spend three or four hours in fatisfying their hunger. The women are condemned by their husbands to drudgery and labour, and acquire a masculine firmness of body. During pregnancy their lot is mitigated; but they are delivered in a private cabbin, without an attendant, and with little pain. The Indians use the cold-bath, and anoint their bodies with bear's-grease mixed with clay, which ferves to diminish the fenfibility of the nerves, and prepare them in fome degree for enduring thofe tortures to

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which they fubmit. Fevers are almost their only diseases; the fmall-pox and the venereal diforder were communicated to the Indians of North America by the Europeans. They permit the patient to drink plentifully of cold water, and recommend sweating. The patient is confined in a clofe tent or wigwam, over a hole in the earth, in which a red-hot stone is placed; a quantity of water is thrown upon this ftone, which inftantly involves the patient in a cloud of vapour and sweat; in this fituation he rufhes out and plunges himfelf, into the river, 'from whence he retires to bed.' The Indians use purges and vomits and the cauftic and aftringent medicines. Bleeding they confme entirely to the part affected; and their inftruments are sharp ftones and thorns. The skill of the Indians in furgery and medicine has been much exaggerated; and their knowledge of the potency of fimples and antidotes has been heightened by ignorance and zeal. Many things have been efteemed poisons, which fubfequent experience has proved to be harmless, or even falutary. Dr. Rush inveighs against the progrefs of luxury and effeminacy, and laments the uncertainty and inftability of the healing art. He bursts into an extravagant and abfurd fwell: I honour the name of Hippocrates; but forgive me, ye vo'taries of antiquity, if I attempt to pluck a few grey hairs from his venerable head. I was once an idolater at his altar; nor ⚫ did I turn apoftate from his worship till I was taught that not one tenth part of his prognoftics correfponded with modern • practice.'

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The fecond tract is an account of the climate of Pennfylvania; which, though irregular and unconnected, contains fone interesting remarks. The ftate of Pennsylvania lies between the 40th and 42d degree of latitude; it extends 157 miles from north to fouth, and, exclufive of the late acceffions, it ftretches 311 miles from the coaft into the interior country. It is interfected and diverfified with numerous rivers, and at a diftance from the sea it is very mountainous. The Allegany crofles the state about 200 miles from Philadelphia, and is called by the Indians the back-bone of the continent. The foil of Pennsylvania is much diverfified; the vallies and bottoms confift of a black mould, but the furface of the earth is in general covered with a deep clay, which in many parts refts upon immenfe beds of limeftone. The climate of Pennfylvania is remarkably variable. In fummer the thermometer fometimes falls, in the courfe of a fingle night, from 90 to 60 degrees. In 1775 it was obferved to fall 20° in the space of an hour and an half. In winter, the variation is often 40° in the courfe of twenty-four hours. On the night of the 31st December 1764 the Delaware, which is about a mile wide near the city, was completely frozen between ENG. REV. VOL. XV. APRIL 1790.

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between ten at night and eight next morning. The fpring in Pennsylvania is generally unpleasant. In March the weather is ftormy, variable, and cold; in April it is damp and cloudy, June is the month when nature wears her moft agreeable robes. The weather is then temperate, the fky is ferene, and the fields and the forefts are painted with univerfal verdure. In July the fun rages with violence, and the air is clear, calm, and fultry. In Auguft the evenings grow cool, and hence abundant dews. Clothes are fometimes wet, and marfh-meadows and creeks, which have been dry during the fummer, are thus fometimes fupplied with moisture. During autumn the weather is mild and. agreeable. The froft fets in about the end of October, or the beginning of November. During winter the cold is intense, and often of long duration. It is curious to obferve that thofe feafons which have been reckoned extraordinary in Europe, have also been confidered as remarkable in America:

The winter of the year 1779, 80, was uniformly and uncommonly cold. The river Delaware was frozen near three months during this winter, and public roads for waggons and fleighs connected the city of Philadelphia, in many places, with the Jerfey fhore. The thickness of the ice in the river near the city, was from fixteen to nineteen inches, and the depth of the froft in the ground was from four to five feet, according to the expofure of the ground and the quality of the foil. This extraordinary depth of the froft in the earth, compared with its depth in more northern and colder countries, is occafioned by the long delay of fnow, which leaves the earth without a covering during the last autumnal and the first winter months. Many plants were deftroyed by the intenseness of the cold during this winter. The ears of horned cattle, and the feet of hogs, expofed to the air, were froft-bitten; fquirrels perifhed in their holes, and partridges were often found dead in the neighbourhood of farmhoufes. The mercury in January stood for feveral hours at 5° below o in Farenheit's thermometer; and during the whole of this month (except on one day) it never rofe in the city of Philadelphia so high as to the freezing point.'

The winters 1779, 80, 1783, 84, and 1788, 89, were all in America remarkably fevere.-Dr. Rush fums up the account of the climate of Pennfylvania in a few words: Here we have the moisture of Britain in the fpring, the heat of Africa in the fummer, the temperature of Italy in June, the fky of Egypt in autumn, the cold and fnows of Norway and the ice of Holland in winter, the tempefts (in a certain degree) of the Weft Indies in every feason, and the variable winds and weather of Great-Britain in every month.'

The medium temperature of the city of Philadelphia is 5410, and the average fall of rain is from 24 to 36 inches. The

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mercury in the barometer generally falls with a foutherly wind and rifes with a northerly.

The fubject of the next effay is the bilious remitting fever which appeared in Philadelphia in the fummer and autumn of the year 1780. The fpring was dry and cool. A catarrh appeared among children from one to feven years old; and in May an intermittent fever prevailed among adults. July and August were uncommonly warm. Many labouring people expired by the exceffive heat, or by drinking cold liquors. children, the fickness and mortality were great. end of August the weather becane fuddenly cool. fignal of difeafe. The epidemic rapidly spread. Intemperance, exposure, the flighteft accident, gave birth to the disorder, and ages and both fexes were affected:

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Among the Towards the This was the

This fever generally came on with rigour, but seldom with a regular chilly fit, and often without any fenfation of cold. In fome perfons it was introduced by a flight fore throat, and in others by a hoarfenefs, which was mistaken for a common cold. A giddiness in the head was the forerunner of the disease in fome people. This giddinefs attacked fo fuddenly, as to produce, in several inflances, a faintnefs, and even fymptoms of apoplexy. It was remarkable that all thofe perfons who were affected in this violent manner, recovered in two or three days.

The pains which accompanied this fever were exquifitely fevere in the head, back, and limbs. The pains in the head were fometimes in the back parts of it, and at other times they occupied only the eyeballs. In fome people the pains were fo acute in their backs and hips, that they could not lie in bed. In others, the pains affected the neck and arms, fo as to produce, in one instance, a difficulty of moving the fingers of the right hand. They all complained more or lefs of a foreness in the feats of thefe pains, particularly when they occupied the head and eyeballs. A few complained of their flesh being tore to the touch in every part of the body. From these circumftances the difeafe was fometimes believed to be a rheumatism; but its more general name among all claffes of people was, the breakbone fever.

Dr. Rush began with emptying the contents of the ftomach and bowels by a gentle vomit of tartar emetic, and by gentle dofes of falts, cream of tartar, or of butter-nut pill. He then gave fmall doses of tartar emetic mixed with Glauber's falts, and recommended cordial aperitive drinks, and bathing the feet at. night. Moft of those who recovered complained of nausea, of the total want of appetite, of wearinefs and faintnefs. Sometimes the convalefcence was attended with dejection of ípirits; in which cafe the Doctor gave the tincture of bark, and the elixir. of vitriol, in frequent dofes. He found that, after the neceffary evacuations were made, the ufe of opium was highly fuccefsful.