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Zurich, he had not the smallest notion of the sciences, or of elegant literature, and consequently no taste for study. The first incident that developed a hidden gern of philosophical gea' nius, was his meeting with Wolf's metaphysics ; this was the birth of his taste for science; but he wanted a guide. The clergyman with whom he lodged was (no uncommon thing!) an ignorant man, and the academical prelections were, as yet, above the reach of his comprehension. On the other hand, a sedentary life was not the thing he liked, nor to which he had been accustomed ; and, moreover, a sociable turn of mind led him often into company, where he loft much time in frivolous amusements, yet without corrupting his morals. Who, that observed him, says Mr. Formey, at this period, would have thought that SULZER would one day be numbered among the most knowing and wiseft men of his time! The learned Gefner was the inftrument of Providence, that rendered Sulzer's inclination to study triumphant over his passion for amusement and company. Animated by the counsels and example of this worthy and learned man, he applied himself to philosophy and mathematics with great ardour, and resumed the pursuit of Grecian literature and the Oriental languages. The contemplation of nature became his noble and favourite passion. An ecclesiastical fetelement in a rural scene, that exhibited happy objects and occasions for this delightful study, began to render his days happy and useful; and he published, in 1741, Moral Contemplations of the Works of Nature ; and, the year following, an Account of a voyage he had made through the Alps; which · Thewed, at the same time, his knowledge of natural history, and the taste and sensibility with which he surveyed the beauties of nature, and the grandeur and goodness of its author. He afterwards became private tutor to a young gentleman at Magden' burg. This procured him the acquaintance of Messrs. Mau. pertuis, Euler, and Sack, which opened to his merit the path of preferment, and advanced him successively to the place of mathematical professor in the King's College at Berlin, in 1747, and to that of member of the Royal Academy in 1750.
In this last quality he distinguished himself in a very eminent manner, enriched the class of Speculative Philofophy with a great number of excellent memoirs, and was juftly conlidered as one of the first-race metaphysicians in Germany. But his genius was not confined to this branch of science. His Universal Theory of the Fine Arts, is a capital production. A profound knowledge of the arts and sciences, and a perfect acquaintance with true taste are eminently displayed in this work, and will secure to its author a permanent and distinguished rank in the republic of letters. The first volume of this excellent work was published in 1771, and the second in 1774. We shall co...
not here give a catalogue of the writings of M. Sulzer ; but we cannot help mentioning his Remarks on the Philosophical Ef fays of the late Mr. Hume, as a work of real merit, which does justice to the acuteness, while it often detects the sophistry of the British Bayle. The moral character of M. SULZER was amiable and virtuous : fociability and beneficence were its characteristical lines ; and his virtues were animated by that facred philosophy that forms the Chrisian, ennobles man, and is the only source of that heart-felt serenity and sedate fortitude, which support humanity, when every other object of confidence fails. His dying moments were calm, humble, and sublime; and when he expired, the placid and composed air of his countenance made his mourning friends doubt, for some time, whether it was death, or sleep, that had suspended his converfation. He had no enemy; and his friends were numerous, affectionate, and worthy of the tender returns he made them.
The king of Prussia diftinguilhed him by repeated marks of munificence and favour. We learn, however, with some furprise, from the eulogy before us, that his royal protector had never seen him before the end of the year 1777, though he had been member of the academy from the year 1750. The audience, indeed, though late vouchsafed, was honourable to M. Sulzer, with whom the monarch conversed for a long time with the greatest affability and condescenfion.
EXPERIMENTAL PHILOSOPHY. Mem. I. An dicount of some Attempts to obtain Kunkel's Red Glass, already coloured, when taken from the Crucible. By M. MARGRAFF. Kunkel's glass is always white and transparent when it comes from the crucible, and only assumes its beautiful red colour when it is warmed at a Aamë.
Mem. II. Experiments relative to a new Method of disengaging the Copper from the Mine. By the same. The celebrated M. Pott is said to have discovered a method of disengaging the copper from its mine by one single fusion, and to have died without communicating to any person the means he employed for this purpose.' At the earneft defire of the late M. Sulzer, our Academician made several trials of this kind, and succeeded. He
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Mem. III. A new Method of extracting Pruffian Blue from all kinds of Cobalt, for the use of China Manufactures. By M. GERHARD.
. Mem. IV. Concerning a new Method of producing, with a very small quantity of Goals, or other inflammable Substances, a Heat equal to that which is obtained by Mirrors and Burning.glasses of a conf. derable size : Together with the Description of a Stove, wbich, while it warms an Apartment, purifies the Air which it contains, by depriving it of its Phlogiflon. By M, ACHARD, It was by trans
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mitting a current of depblogisticated air through burning coals, that our ingenious Academician produced a quantity of heat which the burning body could not have produced in the common atmospherical air, which always contains a certain quantity of phlogiston; and in proportion to this quantity is less proper to accelerate inflammation, as the experiments of Dr. Priestley, often repeated by others, abundantly testify." We refer our Readers to the Memoir for an account of M. ACHARD's Experiments relative to this object. Dephlogisticated air may be obtained in large quantities, with litile trouble, and at a very small expence; and every kind of air may be easily deprived of its phlogiston, as M. ACHARD has fully shewn in this Memoir, and in another contained in the preceding volume. Common air, transmitted by a bellows through fused nitre, loses all its phlogiston by its imperceptible detonation with the nitrous acid, so that it comes de. phlogisticated out of the bellows. The quantity of heat that was added to the fame of a small lamp, by conveying to it a current of dephlogisticated air, melted, in two seconds, a rod of iron one-fifth of an inch in diameter, and made it diffolve in burning drops ; but still greater effects were produced by coals.
Besides the advantages, with respect to the production of an intense heat, that natural philosophy and chemistry may reap from the dephlogistication of common air, effectuated by its transmislion through nitre in fusion, this operation may be employed for a purpose equally important, and in which it will be of more general utility : for, by it, the dephlogistication of the air of an apartment may be carried to any degree that may be judged expedient. The consequence of which this may be to health and spirits is not at all dubious. It is well known how both are promoted by the purity of the air which we breathe ; and our academician has observed hypochondriac persons pass from a state of gloomy anxiety to a state of serenity and comfort, by passing from the common air into an apartment where the air had been dephlogisticated. He gives here an ample description of the easiest method of freeing the air of a room of its phlogiston, in any degree that may be desired. In this method, the same stove that warms the apartment is employed in melting the nitre : and as this would render the operation impracticable, or at least in'olerable, at certain times of the year, when the weather is temperate or warm, on account of the degree of heat required in the ftove to fuse the nicre, M. ACHARD indicates a very ingenious method of remedying this inconvenience. We recommend the perusal of this memoir, in a particular manner, to those who are concerned in the direction of hospicals, where noxious air so often baffles all the efforts of the physician. All we can do is, to i::dicate the sources of APP. Rev. Vol. Ixv.
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useful information.--Want of space must often hinder as front catering into particulars.
Mem. V. Concerning the Analogy that there is between the Production and the Effeets of Electricity and Heat; as also bet weet she Property in Bodies by which they condu&t the eleEtrical Fluid, and that which reders them fufceptible of Heat. To which is added, the Description of a new Inftrument, adapted to measure the Quantity of the electrical Fluid which is conduded by Eodies of a different Nature placed in the same Circumsi ances. By M. ACHARD. This is no more than a short abridgment of an ample memoir, which the indefatigable academician has composed upon this curious subject. It is divided into three parts. In the first, M. ACHARD endeavours to prove, that the preduction of electricity is similar to the production of heat. - In the second he thews, that the effects produced by the electrical fluid are analogous to those produced by the igneous fluid. In the third he proves, that there is a perfect resemblance between the aptitude of bodies to conduct the ele&rical fluid, and their aptijude to receive heat.
In the first part, the point of resemblance is rubbing or friction, by which both electricity and heat are produced. It may be objected, that the analogy here is not perfect ; since metals, and the bodies which are generally considered as conduélors, become electrical, according to the notion commonly received, only by their contact with bodies originally electrical, which are rubbed ; and that the rubbing, directly, these bodies (the conductors), cannot render them electrical. In order to answer this objection, M. ACHARD remarks, that when a body, originally electrical, is electrified by being rubbed against a body which is a conductor, the latter, when insulated, exhibits signs of electricity, as palpable as those which are given by the body that is electrical per fe. Now, says he, this electricity is not communicated to the conductor by the body that is originally electrical, because it is negative in the conductor, when the electricity of the original electric is positive, and vice versa. After having laid down the theory that is deducible from this observation, and is confirmed by facts, our author concludes, first, that rubbing always produces ele&ricicy in all cases, of whatever nature the bodies may be ; and that when the electricity is not palpable, this only proceeds from its being loft in the very moment that it is produced :-secondly, that there is no body, which, being rubbed against aaother that transmits the electrical Auid with more or less dis
culty, does not exhibit marks of electricity; and that metals are as electrical in temselves (per fe) as glass and resins. (This propofitior, says our author, is only contradictory in appearancebe contradiction will vanilh on a close examination.)
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Thirdly, that as rubbing always, and in all cases, produces electricity, the analogy between the production of heat and electricity is perfect. '
In the second part, the points of resemblance between the effects produced by heat and electricity are as follows : 1. They both dilate all bodies. 2. They both accelerate vegetation and germination; and it is remarkable, that positive electricity accelerates vegetation as much as negative : from whence it follows, that the effects of the electrical fluid do not proceed from the augmentation or diminution of its quantity, but from the repulsion of the parts of bodies, which have a degree. of electricity (whether pofitive or negative) different from that of the medium in which they are placed. 3. They both accelerate evaporation. 4. They both accelerate the motion of the blood in animals. 5. They both contribute to the formation and developement of the futus in animals, as appears by our author's experiments on hens-eggs, formerly mentioned ; and those made, by other naturalifts, on the eggs of the butterfly. -6. They both reduce metals, and other bodies, to a state of fusion. These, and other reasons, prove a great analogy between the effects of heat and eleEtricity.
In the third part, the ingenious academician proves, from some curious observations, that several bodies, which receive and lose, with difficulty, their present degree of heat, receive also, and lose, with difficulty, their electricity Repeated and multiplied experiments are necessary to determine, whether or not this law is general and without any exception. To make these experiments, and to compare bodies with refpe&t to their property of conducling the igneous and the electrical fluids, it was necessary to have an instrument capable of measuring and ascertaining the degrees in which bodies conduct electricity. Our academician thinks this a matter of great consequence towards the improvement of the theory of electricity; and is furprised that it has been hitherte entirely neglected. He has, therefore, constructed an instrument, by means of which ic will be possible to ascertain, with great accuracy, the quantity of ele&ricity which a body loses in a given time, by touching another body that is not electrified. For the description and use of this instrument we refer our readers to the memoir itself. M. ACHARD does not give us here an enumeration of the ex. periments he has made with it, nor their results : but these we may expect in some future memoir.
Mem. VI. Concerning the Changes which Earths, mixed with metallic and semi metallic Calxes undergo, when they are exposed to @ Fire that produces Fusion. By M. ACHARD.--This very cu. rious and elaborate memoir is not suscepcible of abridgment. L 12