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to Prop. 15, are undoubtedly the demonstrations which Sis Isaac Newton himself would have given.
The theorem marked (r) pag. 109, is curious, and the de. monstration luch as might be expected from so masterly a hand. Nor must we omit to mention the method of finding two mean proportionals, pag. 152, as it is performed with equal elegance and perspicuity.
In a word, the whole of this commentary is remarkably clear and instructive; but the illustrations of some parts of the gth. fiction, book 1. of the Principia, deserve to be distinguished.
We could however wish that the ingenious gentleman concerned in this work had considered more minutely the lunar inequalities; and we hope that, in the next edition, he will treat that subject in a more copious manner
But a still more acceptable present to the republic of letters would, we imagine, be, a commentary on the whole Principia, executed by the same masterly hand ; being persuaded, that the difficulties which now attend the reading of that celebrated work wou'd then, in a great measure, be removed, and the British youth enabled to peruse the writings of their illustrious countryman with ease and satisfaction, without having recourse to the labours of any foreigner. .
Models of Conversation for Persons of Polite Education. Selected
and translated from the French of M. l'Abbé de Bellegarde. 8vo. 55. Millar. T HE French are doubtless the most artificial and systematic
I people in Europe. They have a whole string of arts and sciences unknown to other nations. Their Arts de Vivre, indeed, are not all of them admitted into the Encyclopedie ; but there is no doubt we shall see many of them in a future edition, or a supplement. Their refinements in the art culinary, in particular, have elevated la bonne chere into a science; while the mere knack of frying pancakes may not be improperly called a profound and fagacious improvement in meta-fritters. As they are not a whit less remarkable also for talking ihan eating, it is no wonder they should attempt, in like manner, to investigate the theory of conversation, and affect a system in the art of discourse. It must be allowed that these lively people appear to be perfectly well qualified for an investigation of the first principles of colloquial loquacity; but we conceive it will he found, on impartial examination, that, although the French talk much in company, they converse less than some other nations, ftigmatized for their taci.
turnity. Conversation is the reciprocal communication of our sentiments, for the improvement or entertainment of each other; and this can be no better supported where all are talking together, than where all are equally filent. The French nation, therefore, appears to be little qualified for furnishing the best rules or models of conversation. Add to all this, that, as there. are talents which cannot be communicated, so there are modes of exerting them which cannot possibly be taught. Of this kind, we apprehend, is the gift or talent of conversing. We are certain, at least, if it be an art, it is to be acquired only by imitation and practice, and never scientifically. The man who hath learned to talk, like a parrot, only by rote, is undoubtedly a coxcomb in his discourse; but he may frequently prove a more agreeable, and even initructive, companion, than the pedant who hath learned to talk only by book.
Admitting, however, that a work of this nature might be of some use to fome sort of readers, it is certainly not those, for whom the models before us are professedly written, viz. persons politely educated: every qualification that is to be acquired in this way, being effected only by a polite education. If this does not qualify us for conversation, we are apprehensive no literary models will have so desirable an effect. But, were the design in general unexceptionable, we should bestow but little applaufe on these specimens of the Abbé de Bellegarde's performance; notwithstanding the approbation it may have met with from many of his countrymen. We shall do him the justice, however, to let him speak a few words in his own recommendation.
Conversation, sayshe, if put to its right use, contributes greatly to sweeten society, and render life more agreeable. There is not perhaps a more exquisite pleasure, a satisfa&tion more dea lightful, than what arises from the acquaintance of men of sense: But the misfortune is, the world abounds with trifiing people, tiresome; infipid, impertinent, and yet full of themselves ; whe, troublesome as they are, affect to put on the man of consequence, and to be thought the soul of company. Such as these make solitude regreted : what they say is low, trivial, and puerile ; barren of any charm for one's attention, vulgar, and uncouth, They are ever talking too, and yet one can distinguish little but found. Is it then any wonder that conversation generally tires ?
• What is still more incomprehensible, is, that certain people, who do not want sense, knowlege of the world, nor yet good breeding, tire you as much as others, and their visits are as wearisome if they happen to be too long. And either this is because they will not be at the trouble of keeping up a conversation, or else have not the address to enter into the taste and genius of the persons they converse with.
“The get by headied or affect hould alone on, we bime subject,
- The great art of pleasing in conversation is to proportion it to the level of the company you are in, and to raise or lower one's style according to the measure of their understandings, and the occasions of the subject you are upon. There is no reason to get by heart what to say; for common conversation admits of nothing studied or affected : chance, the times, and the difposition of the company, should alone give it birth. And accordingly, in these models of conversation, we have not set people a talking for two hours together upon the same subject, till they are quite out of breath : this would have been tiresome. But what we would insinuate herein, is, that morality, history, politics, and the various events of life, are inexhaustible sources of polite conversation, for persons who have any taste for the belles lettres.
• Though the pieces of history herein related are sufficiently detached from each other, yet care has been taken in such manner to adjust and link them together, that they seem so to succeed one another as to form a connected and coherent discourse ; insomuch, that one passes insensibly from one reflection to another, without ever perceiving the difference of the subject. And this variety is perhaps not unacceptable. It will not be unpleasing to men of letters, to find in these conversations, as it were, an assemblage that will put them in mind of what they have read. And others will here discover what they did not know before ; and may hence too learn how to distinguish what is worth remarking in books, and how to convert pasages of history and morality to their own benefit, by rendering them subservient to the civilizing their minds, and the regulation of their own behaviour and moral conduct in lifetime
Thus far our poliMed Abbé: It is after all, however, very cestain, that these discourses might contribute to all the purposcs the Author here specifies, without answering the professed end and intention of them as models of conversation. In this light we conceive them to be extremely defective; being nothing more than a dull repetition of historical anecdotes, now and then interin.xed with a few trite and common-place reflections ; in which all parties so far agree, as to give rise to no fpirit of altercation ; without which, all discourse, however refined, learned, or sentimental, is tedious and insipid. Arsennes, Ariftus and Timanthes, Succellively recite all the several passages they can recollect, from the Greek, Ronian and French histories, relative to the topic of conversation; and then their discourse ends. At :he iame time, none of the interlocutors are invested with any distinguishing character ; the one talking much in the same strain as the other; and just in the same sentiments, except where it is neceffary to introduce two different historical accounts of the same fact or personage. There are perhaps no
models models of conversation superior to the colloquies of Erasmus. Not indeed that they are so polite as those of our Author ; but then they are much less dull in proportion..
We shall not take the trouble to controvert any of this Author's sentiments, or to criticise on the various facts by which they are supported; let it suffice to say, that the former are frequently as absurd, as the latter are improbable. This work had, indeed, but one thing to recommend it, even in the original, and that was its style." Unhappily the Translator has deprived it of even that merit, in his English version, which is most execrable*.
* We conceive the Translator must be a foreigner, as we think no native would make use of the genitive case and the pronoun poffefsive at the same time, as this Writer frequently does. Thus he says, “ Augustus's grandfon, whose murder was but a prelude to that of Germanicus's.' And again, the supported the Duke of Orleans's interests against those of his brother's,'—What Englishman also could be so ignorant of the mean. ing of words, as to say, . A good shepherd will meer the wool, but not fleece his sheep.' What is fleecing, if it be not Meering off the wool ? Fleecing is not flaying, Mr. Transla or! If you are a Frenchman you are the more exç sable in this particular; but a man should understand two languages before he ventures to translate,
Supplement to the Treatise* on Ship-building, containing Extracts
translated from M. Bouguer's Traité du Navire. Together with M. Duhamel's Method of finding the Center of Gravity. With fome occasional Remarks. Also an Account of several Experiments, made to ascertain the form of a Solid which will move with the greatest Velocity through the Water. Likewise a Method to determine the Thickness of the Plank, in the Direction of the Planes of the Timbers. With the Proportions for Mafis, Yards, Caps, &c. By Mungo Murray. 4to. 5s. Millar.
IN the introduction to the work before us, Mr. Murray, after I remarking that capacity and velocity are two essential properties of every ship, very juftly concludes, that it will be absolutely necessary for all ships to be longer than they are broad, and not only tapered at each end, but also from the extreme breadth down to the keel. The next enquiry, he observes,
must be, whether these vertical sections are to be limited with curves or strait lines, and how to ascertain their form. ***
« The mathematicians, adds Mr. Murray, have endeavoured to investigate the forın of that solid, which meets with least resistance in passing through the water ; but they have not drawn See Review, Vol. XI, p. 41.
• must be, we lines, and how. Mr. Murray, h
: The machines, and how callcctions are wry, he obra
any practical rules from thence; to determine the form of a ship, and should they be so lucky, after a tedious calculation, as to find out the particular form of such a solid, it would be of little use in forming the body of a ship: for it is supposed that the solid is to continue in the same position in the water, other.. wise the immerged part will alter its form as often as it alters its position, unless it be, as M. Bouguer would have it, formed by the - Revolution of a curve round its axis. Hence we may conclude, that the particular form of a ship cannot be determined by rules that will admit of a mathematical demonstration.'
Is it posible that a person who has undertaken to abridge so curious a treatise as that of M. Bouguer's Traité du Navire, can be ignorant that the solid of Icaít relistance is formed by the revolution of a curve round its axis ! But if he does not know this, he would do well to peruse the Scholium to the 34th Prop. Book II. of Sir Isaac Newton's Principia ; and the demonftration of that Scholium, inserted at the end of Motte's translation.
The builders, continues our Author, finding they could have very little assistance from the mathematicians, have applied themselves to experience; and though they have not found any pasticular form which may be a standard for all ships of the same burghen, and designed for the same service, yet in some points they seem to agree. Hence it is, that, in ships of war of the fame rate, the principal dimensions are nearly the same; and in all ships the midship frame is nearer the fore-part than the afterpart. For finding, by repeated trials, that a mast, or tree, when tapered, will tow fafter through the water with the burt: end foremost, than with the small end, they conclude it will be so in ships ; though Mr. Bouguer thinks the only realon for towing the but-end foremost is, that the rope may not flip.'
If Mr. Murray means a maf, whose heel or but end is cut tapering, in order to fit the step in the keelson, the result of the experiments he mentions may pofiibly be just: but if he means a maft nearly in the form of a frustum of a cone, whose bases are at right angles to the axis, he must be mistaken, in all probability, from the experiments not having been made with a fufficient degree of accuracy.
For let BC FG represent a maft or tree in the form of a frustum
of a cone. It is well 10.......
known that the resist. ance of the water, or the whole efficacy of the force of all the strokes
of the partiçles of the. Auid against the end FG of the frustuin, is to the resistance