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Philosophy, according to the baron, had its birth in the earliest ages of the world, and owed its origin to that defire of happiness which is so natural tò mankind, that it becomes the motive of all their labours, and the fpring of all their actions.
The first that made open profession of philofophy in Greece, were Thales and Pythagoras, who thought the title of fage too fastidious, and took the more modeft name of philosophers, or lovers of wisdom. Socrates, who followed the career of the earlieft philosophers, turned all his studies towards morality, and was the first to reduce the confused ideas of his predeceffors to some method; for which reason he is called by Cicero, the Father of Philosophy. Of all the celebrated men who came out of the school of Socrates, Plato was the most renowned. He established his school in the Academy, which was a place without Athens, and from thence his followers were called Academics. According to Plato, the foul of man is only an emanation of the divinity. He believed that this particle united to its principle, knew all things; but, when united to a body, contracted ignorance and impurity from that union. He did not follow the example of his master som crates, in totally neglecting natural philosophy. On the contrary, he enquired into many questions, which relate to that Science, and even cultivated astronomy. The disciples of Plato formed also many new sects ; of which that founded by Aristotle is the most illustrious. This philosopher was the first who formed a complete system from the several parts of phi. lofophy. His disciples and his followers were called the Peripatetics of Lyceum, where he had fixed his school. About fixty years after rose the seats of the Stoics and Epicureans, which at first divided the wits of Greece, and afterwards those of all the rest of the world : the founder of the former was Zeno, that of the latter Epicurus. About the twelfth century prevailed a philosophy called the Scholastic, borrowed, in a great measure from the writings of the Arabs, whom the Scholastics, who were all attached to Aristotle, imitated in their subtle, ambiguous, abstract, and capricious manner of reasoning About the sixteenth century, men began to throw off the yoke of Aristotle. Nicholas Copernicus, who was born at Thorn in 1473, had already borne the torch of reason in mathematics and astronomy; he had rejected the system of the world that was invented by Ptolemy, and which the Greeks call most wise and most divine; and in its place introduced the system of the sun's being immoveable, and the motion of the earth. Galileo, who was born at Florence in 1564, adopted the system of Copernicus, and improved it by
new observations. He likewise introduced a new and excellent method of reasoning in philosophical subjects. At last René Descartes appeared, and by a method, but very imperfectly understood before, discovered more truths in philosophy, than all the preceding ages had produced. Before Descartes, Sir Francis Bacon had lighted that torch, with which all his fuc. ceffors have illumined philofophy; and in his writings are to be found the seeds of every new discovery, and every new hypothesis. At length philosophy was carried to its highest perfection by Newton, Leibnitz, and Locke, all living in the seventeenth century, and all cotemporaries.
Thus have we given a general sketch of the history of philosophy, of which our author has enumerated the following branches. i. Logic. 2. Morality. 3. Natural theology. 4. Ethics, or moral philosophy. 5. General philosophy, or common prudence, 6. The policy of nations. 7. The law of nature. 8. The law of nations. 9. Metaphysics. 10. Physics, or natural philosophy.-We Mould exceed the limits which we have prescribed to ourselves, were we to enter into the subdivisions of these branches, or give a particular account of each. With the same view of avoiding prolixity, we shall pass over the article of Mathematics, with which this second book concludes, as what has been said of the other branches of science, is abundantly sufficient to give an idea of our author's. manner of treating his subjeets.
Our opinion of this work, upon the whole, is, that, notwithstanding a few errors, which are excusable in a work so exteo sive, it is equally curious and useful ;-the author has discovered a fund of good sense equal to his profound erudition ; and the translator has performed his part with spirit and fidelity.
[ To be continued. ]
IX. An easy Introduction to Afronomy, for young Gentlemen and
Ladies. The Second Edition. Illuftraled wirb Copper-plates.
By James Ferguson, F.R.S. 8vo. Pr. 55. Cadell. AMONG all the sciences it is probable there are very few,
* if any, which so much enlarge the mind and correct the judgment as that of mathematics ; by this noble art we are led to truth by the nearest way, and likewise, with the greatest certainty. The ancients held this valuable part of learning in such eleem, that their kings were not only encouragers of it, but also students in the latence; they accounted that
per. person anfit to govern the world who knew not what the world was, or bad not, at least, acquired a general notion of the univerfe and situation of the parts and extent of the solar and planetary system : nor have there been wanting persons in early ages, who have cultivated the feveral branches of mathematical knowledge, and in particular astronomy; for by the writings of Porphyry and Simplicius, it appears, that when Alexander the Great took Babylon, Callisthenes, one of Aristotle's fcholars, by the defire of Aristotle, carried from thence to Greece, celestial observations made by the ancient Chaldeans and Babylonians of two thoufand years standing. And Sir Henry Savil, towards the latter part of his second lecture upon Euclid, fpeaking of this, fays, that although the common printed edi. tion of Simplicius mentions but two thoufand years, yet in his manufcript it is thirty-one thousand years; and Cicero, in lib. 1. de Divinatione, forty-seven thoufand years. But as the Greeks had almost all their astronomical learning from the Egyptians, whose observations were purely astrological, and made chiefly with a view to determine the inftuence of the stars, Simplicius's account rather serves to shew the an. tiquity than the advancement of astronomy; nor indeed have we any thing of certainty with respect to the latter, until about 300 years before the Christian æra, when, according to
Prolemy, Tymocris and Aryftillus left several obfervations of · the fixed stars, which proved of great use to succeeding aftro
nomers in determining the precesion of the equinoctial points, and other astronomical phenomena.
The difficulty of arriving at an extenfive knowledge in astroromy, and the time required for that purpose, have induced feveral very considerable writers upon this subject to oblige the world with popular treatises, whereby a sufficient idea of aftronomy may be obtained, with very little trouble, and without any previous knowledge of algebra or geometry. This feems to be the design of the work before us, and which may be considered as excerpta from the writings of thofe celebrated astronomers Keil, Pemberton, Wallis, &c. wherein the ingenious author has illustrated the principles of astronomy by way of dialogue between Neander and Eudosia, in a very easy and compreliensive manner. The figure, motions, and dimensions of the carth, the solar system, the nature of eclipses of the fun and moon, &c. are well explained, and rendered clear to the understanding of those who are unacquainted with geometry or maihematics.-- Our author, in speaking of the nature and laws of gravity, at page 61, and of the difference between folar and fydereal time, at page 207, is not quite so satisfactory as
in the other parts of this performance: the reader will judge of this by the following extracts.
• Eudefra. I thould be glad to know the reason why the fun's attraction decreases in proportion to the squares of the distances from him; Why do you Make your head ?
• Neander. Because you ask me a question which Sir Isaac Newton himself could not solve ; although he was the prince of philosophers.
. E. But can you give me no idea at all of it ?
• N. I could; and a very plain one too, if the attra&tive force, (the effect of which we call gravity) acted only according to the surface of the attracted body.
• E. Your if implies that it does not: but, if it did, why Thould it decrease in that proportion?
• N. I have drawn a figure for your inspection (Fig. 1. Plate 11. in the author's work), which, indeed, is for a quite different purpose: but it would exactly solve your question, if gravity acted as all mechanical causes do ; only upon the fur. faces of bodies.
• E. But, if gravity acts not according to the quantity of surface, pray how doth it a&t ?
N. Exactly in proportion to the solid contents of bodies; that is, to the quantities of matter they contain; for if gra. vity acted according to the surfaces or bulks of bodies, a cork would be as heavy as a piece of lead of the same bulk as the cork.'
This account of gravitation, seems (at least to us) rather defective and confused; for the solid contents of bodiis are not proportional to the quantity of matter they contain, nor are the surfaces of bodies, and their bulks the same thing. Mr. Ferguson should have defined the quantity of matter in a body as Sir Isaac Newion does, to be the measure of the faine arising from its density and bulk conjunctly; and then, indeed, the effect of gravity at equal distances from the center of force. would be as the quantity of matter or weight of the body, nor would this vis in sita, or vis inertia, probably, be changed by any alteration in the present law of gravitation, that is, at the same distance from the center of force the proportion between the vis enertiæ of bodies would still remain the same, namely, that of the quantities of matter or weights of the bodies themselves, whether the force of gravity acted as it now does, or by any other law. We are therefore of opinion, that, even grants ing the force of gravity upon bodies at equal distances from the center of attraction to be as their surfaces, it could not be proved from thence that the law of attraction Mould be reci. procally as the square of the distance from that center, for the
'influence of attra&tion at different distances from the center of force remains just the same, and increases or decreases in the very same manner, whether there are any bodies or not within the sphere of its activity; whereas our author (in his hypothesis, makes the force of atrraclion propagated from the cen. ter, depend upon the magnitude of the surface of the attraded body; confequently by Mr.Ferguson's scheme (plate III. fig. 1.) it will appear that the force of gravity upon a body, at the earth's surface, whose superficies is one inch, is no greater than the force of gravity upon a body at two femidiameters from the earth's center, whose surface, is four inches. This we apprehend would fall very Mort of confirming the prelent law of gravitation.
At page 243 it is said, that 24 solar hours are 3 minutes and 56 seconds longer than 24 fydercal hours. Now as the fydereal day contains only 23 hours 56 minutes and 4 fęcoi:ds, and the difference between the rolar and sydereal year is no more than 20 minutes 17 seconds and }, we think Mr. Ferguson Mould have added a line or two, in order to have explained to his readers, the reason of the solar day being 24 hours.
We have here enumerated the chief, and indeed the only, difficulties we met with upon reading this Introduction 10 Astronomy, in which, we apprehend, there is much more to be praised than pardoned ; and therefore, recommend it to the perusal of those young gentlemen and ladies, who are desirous of obtaining a competent knowledge of astronomy, without being obliged to acquire any previous knowledge of geometry or mathematics.
X. A Skort Esay on Military Firft Principles. By Major Thomas
Bell. 8vo. Pr. 45. Becket and De Hondt. JT gives us pleasure to behold a performance, in which the I principles of the military art treated of in so clear and rational a manner, as in the Effay before us. We are here prefented, not with dry and arbitrary rules of martial discipline, drawn from the practice on the parade ; but the author lays before us the grand and leading principles of the several kinds of military operations, and from thence de luces, by the faireit conclusions, every essential circumstance which regards the improvement of the art. This ingenious system is not only founded on the justest principles, but is also illustrated and supported by examples, boch from ancient and modern his: tory.