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thod offered by Mr Hardy, in the pamphlet before us; which is by the appulfes of the moon to the meridian of the place. In order to this, he lays down the following propofition : • The right afcenfion of the fun when he is upon one meridian differs from his right afcenfion when upon another meridian and this difference is to the horary difference of those meridians, as the increafe of the fun's right af cenfion in 24 hours to the fpace run over by a meridian in the fame time.'

From this propofition he deduces the following lemma * Although when the fun comes to the meridian of any place, it is always 12 o'clock at that place, and fo no horary difference can be difcovered merely by obferving the time of his appulfe to different meridians; yet the moon comes not to all meridians at the fame time, but at times differing from one another in proportion to the velocity of the moon in her orbit, and the diftance of those meridians from each other.

This feems to have been but little attended to; yet every astronomer will affent to it as foon as it comes to be explained. Let us fix upon London for one meridian, and let us fuppofe another distant from it 28 degrees weftward. This converted into time: =1 hour 52 minutes. The moon is continually fhifting eastward: fuppofe then that the moves at this time 15 degrees in 24 hours; that is, I degree 10 minutes in 1 hour 52 minutes. Suppofe then, that the moon is obferved to be upon the meridian of London at 12 o'clock, P. M. it is now at our meridian 10 hours 8 minutes, P. M. But by that time it is twelve o'clock P.M. at this latter meridian, the moon will be eastward from it I degree 10 minutes. And therefore, this meridian muft go fo much farther eastward before it will pass through the moon; that is, it will be 12 hours 4 minutes 40 feconds at this meridian when the moon is upon it. Now the faster or flower the moon moves, the later or fooner will this meridian overtake her; and the farther any meridian is diftant from this, eaftward or weftward, the fooner or later will that meridian arrive at the moon; which is what we propofed in our lemma.

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From whence we may deduce an easy method for difcovering the longitude of a fhip at fea, fuppofing the moon's theory to be known. For then we can certainly calculate the time of the moon's appulfe to each meridian, and make proper tables of fuch her motion. Suppofe we then, that

that we have a table fhewing at what time the moon comes to the meridian of London each night in the year. We have alfo a table for the moon's hourly motion, and fo for any smaller time; confequently, we have the difference of time between the appulfe of the moon to the meridian of London and a meridian 1 degree eastward and weftward. Let us then fuppofe every thing as in the preceding lemma: in this cafe for every degree of longitude we are to allow 10 seconds. Suppofe then I was at fea, and by obfervation I found that the moon was upon the meridian of the fhip at 11 o'clock, P. M. By the tables juft mentioned, I found, that the moon came to the meridian of London this fame night, at 10 hours 55 minutes 20 seconds, P. M. The difference of time then is 4 minutes 40 feconds 280 feconds; which divided by ten feconds, the quotient will be 28 degrees, which is my true diftance weftward from London.

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Thus it appears that this method is true in theory : but I am aware that it will be objected, that the theory of the moon is not perfect enough for our purpose. Her inequalities are not fufficiently known, fo as to calculate her true place nearer than two or three minutes of a degree and if her true place cannot be determined, then, neither can the true time of her appulfe to any particular meridian be determined.

But this is no objection to our present method; for the error of appulfe, will always be in proportion to the error of her place and in the fame proportion will be the difference of time between her appulfe at the meridian of London, and a meridian distant from thence degree eastward and weftward; while the time of appulfe to the meridian of the fhip is had from immediate obfervation; and fo has no dependance on the aforefaid calcutions. Though therefore the time of her appulfe to the meridian of London and the meridian of the fhip be greater or less than it fhould be; yet because the number by which that time is to be divided is always greater or lefs than it should, in the fame proportion as that time is greater or lefs than it should be, the quotient will still be the fame; and this quotient is no other than the difference of longitude in degrees. All this is very clear from the doctrine of proportion: for, if the divifor and the dividend be diminished in the fame proportion, the quotient will ftill be the fame.’

The author then proceeds to fhew how to correct any errors in the longitude by obferving the culmination of a

ftar.

ftar. And alfo how to multiply the opportunites of dif covering the longitude, by fhewing how it may be found by an obfervation of the moon in any other situation.

But the principal thing which at prefent feems wanting to render this and the former methods practicable at fea, is a true knowledge of the hour of the day or night, when any obfervation is made. And with regard to Mr. Hardy's method, the chief difficulty is to find the exact time of the moon's appulfe to the meridian, which by the methods at prefent in ufe at fea, feems almoft impoffible. It is well known to those who have made obfervations upon the sea, how difficult it is to obtain the altitude of the fun to two or three minutes, even by that noble inftrument lately invented by the learned Mr. Hadley; and confequently the appulfe of the fun or other object to the meridian, can hardly be obtained fo near as one minute, which will produce a prodigious error in the longitude. Indeed, upòn the land, by the help of good inftruments, especially by a mural arch, the time of appulfe may be found to the greateft exactness; but this is not the cafe at fea; the mariner is exposed to unavoidable errors in his obfervations, which flow from different quarters; especially from the prodigious motion of the fhip.

But it is well known, that if a method ever so easy were propofed for finding the longitude at fea, it could not be put in practice, with any defireable fuccefs, till the longitudes of the fea-coafts were better determined; for it is very certain, that the furer any man is of the longitude of any place at fea, the furer he is to miss the port he is defigned for if the longitude of that place be not truly determined; and therefore, the first thing neceffary to be done, is to have all our fea-coafts better fettled, and new fea charts form'd let this be first executed, and the fuccefs of these observations will doubtlefs encourage them to put these methods in practice at fea; for things which we are unacquainted with, generally feem more difficult than they really are, and experience often renders those things eafy, which at firft fight we thought impoffible.

ART.

ART. XIX. HERMES; or, A Philofophical Inquiry con cerning Language and Univerfal Grammar. By James Harris. 8vo. 6s. Nourfe and Vaillant.

THE

HE fubject of the performance now before us, how ufeful foever, is, at beft, but dry and unentertaining, and cannot easily be handled in fuch a manner as to be agreeable to the generality of readers. Our learned and ingenious author, however, has treated it with great accuracy and precifion, and fhewn a thorough acquaintance with the beft ancient grammarians and philofophers, from whose writings he has filled his book with a multiplicity of quotations. He has not confined himself entirely to what is promised in the title-page of his work, but has expatiated freely into whatever is collateral, aiming, as he tells us in his preface, on every occafion to rife in his enquiries, and to pass, as far as poffible, from small matters to the greateft.

The whole work is divided into three books; in the two firft of which language is refolv'd, as a whole, into its conftituent Parts. Our author begins from a period or fentences which, after Ariftotle, he calls, a compound quantity of found fignificant, of which certain parts are themfelves alfo fignifi cant. All the different species of sentences he reduces to two claffes, viz. fentences of affertion, and fentences of volition, referring them to the two leading powers of the foul, perception and volition. After this he proceeds to treat of words, the fmalleft parts of fpeech. Now thefe, he tells us, are all either fignificant by themselves, or fignificant by relation: if fignificant from themselves, they are either fubftantives or attributives; if fignificant by relation, they are either definitives or connectives. So that, under one of these four fpecies, fubftantives, attributives, definitives and connectives, or, in other terms, nouns, verbs, articles and conjunctions, he includes all words however different.

Having reduced all words to these four claffes, he goes on to give each of them a diftinct and feparate confideration, and begins with fubftantives, which, he tells us, are either primary or fecondary, that is to fay in a more familiar language, nouns or pronouns. The nouns denote fubftances, and those either natural, as man, oak, &c. artificial, as houfe, fhip, &c. or abftract, as motion, virtue, &t. They inoreover denote things either generals or special, or particular. The pronouns, their fubftitutes, are VOL. VI.

K

either

either prepofitive or fubjunctive, The prepofitive is diftinguished into three orders, called the first, the fecond, and the third perfon. The subjunctive, (who, which, that) includes the powers of all thofe three, having fuperadded, as of its own, the peculiar force of a connective.

Having done with substantives he proceeds to attributives, which he divides into thofe of the firft, and thofe of the fecond order. Verbs, participles, and adjectives, as denoting the attributes of fubftances, he calls attributives of the first order; and adverbs he calls attributives of the fecond order, as denoting attributes of attributes. He treats fully and diftinctly of the various species and attributes of verbs, and bestows a long chapter on time and tenfes, which being a curious fubject, we thall present our readers with the greatest part of what he fays upon it, as a fpecimen whereby they may, in fome measure, judge of the reft of his performance.

Time and Space, fays he, have this in common, that they are both of them by nature things continuous, and as fuch they both of them imply extenfion. Thus between London and Salisbury there is the extenfion of Space, and between yesterday and to-morrow, the extenfion of time. But in this they differ, that all the parts of space exist at once and together, while those of time only exift in tranfition or fucceffion. Hence then we may gain fome idea of time, by confidering it under the notion of a tranfient continuity. Hence alfo, as far as the affections and properties of tranfition go, time is different from fpace; but as to those of extenfion and continuity, they perfectly coincide.

• Let us take, for example, fuch a part of space, as a line. In every given line we may affume any where a point, and therefore in every given line there may be affumed infinite points. So in every given time we may affume any where à now or Inftant, and therefore in every given time there may be affumed infinite nows or inftants.

Farther ftill-A Point is the bound of every finite line; and a Now or Inftant, of every finite time. But although they are bounds, they are neither of them parts, neither the point of any line, nor the now or inftant of any time. If this appear ftrange, we may remember, that the parts of any thing extended are neceffarily extended alfo, it being effential to their character, that they should measure their whole. But if a Point or Now were extended, each of them would contain within itself infinite other Points, and infinite other Nows (for thefe may be affumed infinitely within the minuteft extenfion) and this, 'tis evident, would be abfurd and impoffible.

• Thefe

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