history of chemistry, a science, embrating the whole of natural phenomena; since, comparatively speaking, there are few changes but what are attended with effects which fall within its consideration. Its importance to the potter, the refiner, the brewer, the distiller, the agriculturist, the apothecary; and lastly, as applying to the preparation of our food, was clearly shewn.

The rise of this art among the Egyptians, its subsequent extinction in the dark ages, its revival amongst the Arabians in the ninth century, the progress of it in the days of Alchemy, in those of Paracelsus, and from the earliest period when it began t› be treated. in a philosophical manner to its present state, were traced in a pleasing and comprehensive manner.

7th. In the evening the scientific course of astronomy was pursued. The apparent motions, magnitudes, and changes, of the heavenly bodies were described, and the different hypotheses on, which the celestial phenomena have been accounted for by different. philosophers explained, particularly the system of Newton.

8th. The laws of chemical attraction were described. It was. shewn, that besides the attraction existing between particles of the same kind, bodies of different natures exert upon each other an at- : traction more or less strong, and that all chemical changes are pro-, duced by means of this property. The laws which regulate the attraction of combination were next detailed, as well as the diffe.. rent names given by chemists to the affinity of combination according to the effects produced. The lecture concluded with remarks. on the controversy respecting the question, Whether the attrac-. tion of cohesion and combination be the same force that Newton, denominates gravity?

10th. The subject of the last evening lecture continued.

11th. The motions of the earth round the sun, of the moon round the earth, and the planets round both, were explained and shewn by. appropriate machinery. The changes of the moon, and of the seasons, were described and accounted for; the relative distances of the planets from each other pointed out; the discoveries of Dr. Herschel enumerated; and other curious astronomical phenomena

described.

13th. The professor entered on the important subject of heat. He shewed that the terms hot and cold as vaguely used in common discourse, and as applied to our bodily sensations, have only a relative signification; and that in order to avoid error it is necessary, in all experiments, to use some invariable standard. The effect of heat in the expansion of bodies was explained and demonstrated by heating in the fire an iron pin previously fitted to its ring, as well as by other experiments equally decisive. The power which different bodies possess of conducting heat, formed a very interesting part of this lecture.

14th. On this evening the properties of matter, and the doctrine of central forces, were explained. The production of motion and rest, the ultimate causes of resistance, the communication, of power, the motion produced by two or more powers acting upon a body in different directions, the multiplication and increase of power, &c. were spoken of.

15th.

15th, Thermometers and their construction were explained. The method of obtaining a knowledge of the extremes of heat and cold in the atmosphere, by an ingenious contrivance of Mr Sixe, was also shewn; and that of Mr. Wedgewood for measuring the degrees of heat in such situations as would melt the glass of a common thermometer. This lecture concluded with a full account of Dr. Black's theory of latent heat.

17th. The subject of the last evening lecture was continued.

18th. The solar system was farther explained, and the nature of . comets pointed out. The professor urged many reasons in support of the conjectures of some philosophers as to a plurality of aworlds; and endeavoured to shew the probability of the sun even being inhabited, as has been maintained by Dr. Herschel,

19h. The evening lecture consisted of a discourse on the mechanic powers; in which the principles of the lever, wheel and axle, pulley, inclined plane, wedge, and screw, were severally demonstrated. These subjects were illustrated by models, and their application to the useful purposes of life fully set forth.

20th. In a former chemical lecture, Dr. Black's simple and be autiful theory of latent heat having been given, the professor entered on the experiments necessary to confirm that theory. He shewed, that when solids become fluids they absorb a great quantity of heat, which remains in a state not evident to the senses; and that when they are changed back to their former state they give out this heat again. On this principle he accounted for the great degrees of cold produced by a mixture of different salts with the mineral acids, by which means even quicksilver may be frozen. 'The water of crystallization in these salts absorbing a great quantity of heat, accounts for the extreme degree of cold produced by freezing mixtures. A familiar example of the production of ice by artificial means, was cited in the process for making iced creams.

Having concluded this subject, the doctor passed to that of heat under its various modifications and appearances, and explained the phenomena that present themselves when fluids are made to boil, or are converted into elastic or aëriform substances. He shewed that the operation of heat in producing vapour is similar in its operation in producing fluidity; that, when a fluid is heated up to its boiling point, it absorbs a large quantity of heat, and becomes aëriform, and that this heat becomes latent. He farther observed, that fluids, when once brought to their boiling point, cannot be heated beyond that; and that in culinary processes, where attempts are made to expedite the cooking of meat by causing the water to boil violently, a great waste of fuel occurs without any advantage.

21st. This evening the subject of mechanics was resumed, attraction and gravitation were considered, and their general laws pointed out. The subject of pendulums was then taken up, their vibrations in circular and cycloidal arches described, together with the methods of measuring the descent of heavy bodies in a given time by them. Dr. Garnet then proceeded to the doctrine of projectiles, and after having demonstrated that the path of a projectile in vacuo is a parabola, he observed that the air's re

fiftance

E

sistance causes the path of the body to deviate so much from the parabola, that this theory is now considered of little use in directing the practice of the engineer. To these remarks were added some observations on friction, and the means of diminising it in the construction of machines; the whole illustrated by experi

ments.

22d. The subject of heat continued. All the different forms under which bodies appear were shewn to depend on the latent heat, or caloric, which is combined with them: but their permanency, or continuance in any form, depends on the degree of their temperature or sensible heat. Water is solid in all degrees below thirty-two: it is then disposed to combine with caloric, and become a fluid; it retains its fluidity under the ordinary pressure of the atmosphere, till its sensible heat is augmented to 212°. It then absorbs a much larger portion of caloric, and is converted into an elastic vapour or gas, in which state it would always continue if the heat of the atmosphere exceeded its own heat, The same law applies to other fluids. Evaporation, sublimation, and distillation, were explained on these principles. The production of cold by evaporation was accounted for, and demonstrated by moistening a small glass tube containing water, with a mixture of equal parts of vitriolic and muriatic ether, and waving it in the air to quicken the evaporation, by which means the water was frozen. The effects of evaporation were traced in a very interesting way to the forma tion of clouds, mist, and rain.

Ignition was next considered. It was shewn, that there exists a curious connection between light and heat, since a body intensely heated becomes luminous, and on the other hand, the concentrated rays of light from the sun produce heat. An account of the physical properties of light, as connected with chymistry, was given; and at the conclusion of the lecture, Dr. Garnet made the experiment of producing combustion by the mixture of nitrous acid with oil of turpentine, which is supposed to be the Greek fire of the ancients.

24th. The effects of friction were farther considered, and the means by which it may be diminished. The application of this subject to wheel-carriages, the advantage of large over small wheels, the most judicious way of placing heavy loads in carts, and many other interesting particulars relating to this subject were dwelt on. The doctrine of central forces concluded the lecture.

25th. On this day two lectures were delivered. In that of the morning, the causes of the celestial motions were pointed out; the revolutions of primary planets round the sun, and of the secondary planets round the several primary planets, by the compound action of a projectile and centripetal force (which last agrees with gravity in its quantity and direction,) demonstrated by experiments. The professor illustrated the action of these forces by a very simple contrivance, which shewed that a body under the action of a projectile and centripetal force would move in an eliptic orbit. He next proceeded to explain the cause of the tides; in doing which he de fended the Newtonian theory, and explained the moon's inflagree very satisfactorily. The methods of determining the latitude and

longitude

longitude of places, with the difficulties attending the latter subject, were explained at considerable length.

The exhibition of the astronomical lucernal proved a powerful attraction to the subscribers in the evening. By this curious machine the respective motions of the heavenly bodies were represented in the happiest manner, and the explanations which accompanied them gave great satisfaction.

26th. The doctrine of central forces was continued this evening, and the several propositions were illustrated by the help of the whirling table, a method which conveys a clear idea of this intricate subject, even to those who do not possess any degree of mathematical knowledge. These propositions were then applied, agreeably to the Newtonian system, to account for the motions of the heavenly bodies.

The laws of chemical combination, the effects of mixture, solution, &c. were explained. The method of separating from each other the constituent parts of bodies, the construction of furnaces,. and the apparatus necessary for chemical operations, occupied the remainder of the lecture,

31st. Dr. Garnett began his lecture this evening by informing his audience, that though what he should say on heat in the evening. Lectures would be confined chiefly to its mechanical effects, yet he should be under the necessity of repeating some of his observations on its chemical properties, otherwise the subject would be incomplete to those who had it in their power to attend the evening course only. He observed, that two opinions had long divided, and did still divide the philosophical world respecting the nature of heat. The one was, that it consists in a peculiar motion or vibration of the parts of bodies; the other supposes, that heat is a substance or fluid, whose greater or less quantity causes a higher or lower temperature. This enquiry, however, as being neither useful nor necessary in the first steps of the investigation, he declined entering into, observing, that we may speak of the quantities of heat in bodies, whether these quantities or intensities be caused by quantities of motion or quantities of matter.

Expansion was considered and demonstrated. To this the errors in time picces are to be attributed; brittle substances, as glass, &c. Frack by sudden heat or cold applied to them. Water, indeed, shown to be an exception, not contracting but expanding violently by freezing, The cause of this expansion, the doctor observed, has not been properly explained, but may, perhaps, depend on some kind of polarity in the attraction which disposes the particles of water to unite into a solid when their heat is sufficiently diminished, and which, at the same time, forces them to run into certain lines or figures, instead of uniting simply together; in consequence of which, little vacancies are left in the mass, Causing it to occupy more room.

In this manner the lectures were regularly continued to the termination of the session, on Tuesday, June the 10th, when the professor took leave of his audience by a respectful and elegant address, in which he apologized for the deficiences of the course.

SOCIETY

SOCIETY OF ANTIQUARIES, LONDON.

This society has published the thirteenth volume of Archæologia, nsisting of tracts read at their meetings, from April, 1796, to January, 1799.

ORIENTAL SOCIETY, LONDON.

The Oriental society, of which we mentioned the institution in a former number of the Museum, is now about to publish a quarto volume of essays and miscellaneous papers, under the superintendance of Sir WILLIAM OUSELEY,

POLITICAL OCCURRENCES.

JULY, 1800.

:

and ful

lowing day received the congratulations of the constituted authorities, on his recent splendid victory.

His Majesty went in state to the House of Lords, to give the Royal Assent to the Bill for incorporating the Kingdoms of Great Britain and Ireland into one great and potent Empire.

The first stone of the new Wet Dock, at the Isle of Dogs, laid by the Right Hon. William Pitt.

General Lecourbe, after defeating the Austrians, possessed himself of Feldkirk, Coire, and all the country of the Grisons.

The Queen East Indiman blown up at Brazil, and about eighty of the persons who were on board of her unfortunately perished.

An armistice concluded in Germany between Generals Moreau and Kray; in consequence of which, hostilities were immediately discontinued.

A smart action took place off Ostend, between his Majesty's ship Nemesis and a Danish frigate, called the Freya. The Dane first fired at the boats of the Nemesis, while going to examine the papers of her convoy. The conflict lasted an hour and twenty minutes, when the Dane struck, with her convoy, to the British flag, and was brought Into the Downs.

The emperor of Germany restored the new pope, Pius VII. to -the full possession of his government of the ecclesiastical states in - Italy.

Preliminaries of peace between Austria and France, at Paris, by count St. Julien and M. Talleyrand, which however the emperor refused to ratify.

The Russian men of war, which had been so long in our ports sailed from Portsmouth for their own country, with a number of transports, having on board the remains of the Russian troops engaged in the expedition against Holland.

AUGUST.

The Irish parliament prorogued never to meet again.

Lord