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any length of time, contains a mixture of carbonic and azotic gases, the last of which would form nitric acid with oxygen. Hence it is easy to account for the adventitious portion of acid. With regard to the quantity of water diffolved in air, it is found to be extremely small. Carbonic gas has indced a stronger attraction, and retains a large portion in solution.

Art. XII. Some Observations on the Irritability of Vegetables. By James Edward Smith, M.D. F.R.S. Nature ascends through her productions by minute and insensible gradations. A striking analogy in the structure and physiology subfifts between animals and vegetables. Every plant possesses, in some degree, that principle of irritability, which was once con. ceived to be the characteristic of aniinal life. The delicate senfibility of the mimosa, sensitiva and pudica has long been admired. The dionæa muscipula, from Carolina, manifests this quality in a more remarkable manner ; it grasps the insects that alight upon it, and transfixes them with its prickles. In the barberry, berberis communis, the stamina are extremely irritable. Dr. Smith has examined this subject with attention, and finds that this quality is confined to that side of the filament next the germen. Upon touching that part with a fine bristle, feather, &c. the ftamina spring forwards with great vigour from the petals, under which they were sheltered, to the stigma.

Dr. Smith, like many of the disciples of Linnæus, is fond to indulge in the search of final causes. But this is not the province the philosopher. He then leaves the field of reason to foar in the aerial regions of fancy. How many instances does the history of philosophy record of imagined design, which were afterwards exploded ? and how much did these contribute to retard the progress of discovery?

Art. XIII. An Account of Experiments made by Mr. John M‘Nab, at Albany Fort, Hudson's Bay, relative to the freezing of Nitrous and Vitriolic Acids. By Henry Cavendish, Esq. F.R.S. and A.S. It would be tedious and uninteresting to give a detail of these experiments. We shall content ourselves with an abftract of the result. It appears that spirit of nitre suffers not only an aqueous congelation, in which the watery pait chiefly freezes, but also a spirituous congelation, in which the acid itself freezes. When the strength of the acid is such as not to dissolve so much as .243 of its weight of marble, it is liable to the aqueous congelation solely; and this congelation takes place at 44° below the freezing point, or at a higher temperature, according as the strength of the acid is diminished. When the strength of the acid is .418, it undergoes the spirituous congelation at the least degree of cold, which is 2°{ below the freezing point; and, if the acid be either stronger or weaker,

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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 strength' at which the heats of its freezing points are minima. At the strength 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 president 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 Observations. To which is added

an Appendix, containing Observations on the Duties of a Physician, and the Methods of improving Medicine. By Benjamin Rush, M.D. Professor of Chemistry in the University of Pennsylvania. The Second Edition. 8vo. 45. fewed. Philadelphia, printed: Dilly, London. 1789. R. Rush possesses fome ingenuity, and, unlike the generality

of his countrymen, writes with considerable correctness and elegance. His genius is versatile and specious; his ideas are confused, unconnected, and often extravagant. His language sometimes grovels with vulgarisms, but oftener it swells with falfe eloquence. The first essay in this collection, read before the American Philosophical Society at Philadelphia in 1774, is an inquiry into the natural history of medicine among the Indians. The children are plunged every day in cold water, and are suckled 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 shape, they are tied to a board, when they lie on their backs for fix, ten, or eighteen months. The Indians use'a diet partly animal and partly vegetable; their animals are wild, and therefore easy of digestion. They have no set time for eating, and, after whole days spent in the chace or in war, they often commit great excesses. 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 serves to diminish the sensibility of the nerves, and prepare them in some degree for enduring those cortures to which they submit. Fevers are almost their only diseases; the small-pox and the venereal disorder 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 close 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 stone, which instantly • involves the patient in a cloud of vapour and sweat; in this ' situation he rushes out and plunges himself, into the river, < from whence he retires to bed.' The Indians use

The Indians use purges and vomits and the caustic and astringent medicines. Bleeding they confme entirely to the part affected; and their instruments are sharp stones and thorns. The skill of the Indians in surgery 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 esteemed poisons, which subsequent experience has proved to be harmless, or even salutary. Dr. Ruth inveighs against the progress of luxury and effeminacy, and laments the uncertainty and instability of the healing art. He bursts into an extravagant and absurd swell: < 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 prognostics corresponded with modern practice.'

The second tract is an account of the climate of Pennsylvania; which, though irregular and unconnected, contains fone interesting remarks. The state of Pennsylvania lies between the 40th and 420 degree of latitude; it extends 157 miles from north to fouth, and, exclusive of the late accefions, it stretches 311 miles from the coait into the interior country, It is intersected and diversified with numerous rivers, and at a distance from the sea it is very mountainous. The Allegany croffes the state about 200 miles from Philadelphia, and is called by the Indians the back-bone of the continent. The soil of Pennsylvania is much diversified; the vallies and bottoms consist of a black mould, but the surface of the earth is in general covered with a deep clay, which in many parts refts upon immense beds of limestone. The climate of Pennsylvania is remarkably variable. In summer the thermometer sometimes falls, in the course of a single night, from go to 60 degrees. In 1775 it was observed to fall 20° in the space of an hour and an half. In winter, the variation is often 40° in the course 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



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between ten at night and eight next morning. The spring in Pennsylvania is generally unpleasant. In March the weather is stormy, variable, and cold; in April it is damp and cloudy, June is the month when nature wears her most agreeable robes. The weather is then temperate, the sky is ferene, and the fields and the forests are painted with universal verdure. In July the sun rages with violence, and the air is clear, calm, and fultry. In August the evenings grow cool, and hence abundant dews. Clothes are sometimes wet, and marsh-meadows and creeks, which have been dry during the summer, are thus sometimes supplied with moisture. During autumn the weather is mild and agreeable. The frost sets 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 observe that those seasons which have been reckoned extraordinary in Europe, have also been considered 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 sleighs connected the city of Philadelphia, in many places, with the Jersey fhore. The thickness of the ice in the river near the city, was from fixteen to nineteen inches, and the depth of the frost in the ground was from four to five feet, according to the exposure of the ground and the quality of the soil. This extraordinary depth of the frost in the earth, compared with its depth in more northern and colder countries, is occasioned 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 destroyed by the intenfeness of the cold during this winter. The ears of horned cattle, and the feet of hogs, exposed to the air, were frost-bitten; squirrels perished in their holes, and partridges were often found dead in the neighbourhood of farmhouses. The mercury in January stood for several hours at 5° below o in Farenheit's thermometer; and during the whole of this month (except on one day) it never rose 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 severe. Dr. Rush sums up the account of the climate of Pennsylvania in a few words: “Here we have the 6 moisture of Britain in the spring, the heat of Africa in the • fummer, the temperature of Italy in June, the sky of Egypt + in autumn, the cold and snows of Norway and the ice of Hol

land in winter, the tempests (in a certain degree) of the West • Indies in every season, and the variable winds, and weather of 6 Great-Britain in every

month.' The medium temperature of the city of Philadelphia is 54 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 southerly wind and rises with a northerly.

The subject of the next essay is the bilious remitting fever which appeared in Philadelphia in the summer and autumn of the year 1780. The spring was dry and cool. peared among children from one to seven 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. Among the children the fickness and mortality were great. Towards the end of August the weather becarie2 suddenly cool. This was the signal of disease. The epidemic rapidly spread. Intemperance, exposure, the flightest accident, gave birth to the disorder, and all ages and both sexes were affected : :

This fever generally came on with rigour, but feldom with a regular chilly fit, and often without any sensation of cold. In some persons it was introduced by a flight sore throat, and in others by a hoarseness, which was mistaken for a common cold. A giddiness in the head was the forerunner of the disease in some people. This giddiness attacked so suddenly, as to produce, in several infiances, a jaintness, and even symptoms of apoplexy. It was remarkable that all those persons who were affected in this violent manner, recovered in two or three days.

• The pains which accompanied this fever were exquisitely severe in the head, back, and limbs. The pains in the head were sometimes in the back parts of it, and at other times they occupied only the eyeballs. In some people the pains were so acute in their backs and hips, that they could not lie in bed. In others, the pains affected the neck and arms, so as to produce, in one instance, a difficulty of moving the fingers of the right hand. They all complained more or less of a foreness in the feats of these pains, particularly when they occupied the head and eyeballs. A few complained of their flesh be ing iore to the touch in every part of the body. From these circumitances the disease was sometimes believed to be a rheumatism; but its more general name among all classes of people was, the breakbone f-ver.'

Dr. Rush began with emptying the contents of the stomach and bowels by a gentle vomit of tartar emetic, and by gentle doses of salts, cream of tartar, or of butter-nut pill. He then gave small doses of tartar emetic mixed with Glauber's falts, and recommended cordial aperitive drinks, and bathing the feet at, night. Most of those who recovered complained of nausea, of the total want of appetite, of weariness and faintness. Sometimes the convalescence was attended with dejection of spirits ; in which case the Doctor gave the tincture of bark, and the elixir of vitriol, in frequent doses. He found that, after the necessary evacuations were made, the use of opium was highly successful. S 2


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