Mr. Glenie proceeds to recite the leading difcoveries of Mr. Robins, in his New Principles of Gunnery. It appears from accurate experiments made by that ingenious mathematician and obferver, whofe untimely death cannot be fufficiently regretted,

that the refiftance of the air, even to a velocity of 400 feet per fecond, is fomewhat greater than in the duplicate ratio of the velocity; and that, to the fwifter motions of mufket or cannon-fhot, the refiftancé exceeds this ratio, nearly in the ratio of 3 to 1. He likewife was the firft who difcovered that a bullet, fired from an ordinary mufket or cannon, befides being affected by the refiftance of the air, and the action of gravity, receives a whirling motion, or rotation round an axis, the pofition of which is not at all conftant, but uncertain and variable; and that this rotatory motion is the real cause why the track of the ball is doubly incurvated, and carries it to a confiderable diftance from the plane paffing through the axis of the piece perpendicularly to the horizon. This lateral deflection or deviation from the incurvated line, which the bullet defcribes in paffing through the medium by the action of gravity alone, very much diftreffed Mr. Robins in making his experiments. The existence of this motion he clearly demonftrates; the difficulty he acknowledges, and feems abundantly fenfible, that it muft introduce a degree of uncertainty into all conclufions drawn from experiments made with pieces generally in ufe." Our Author has already had fome opportunity for making experiments with rifled field pieces, but not fufficient to enable him to pronounce pofitively with regard to the accurate law of the air's refiftance. He propofes to purfue his inquiries and calculations, and to illuftrate the principal propofitions in the fecond book of the Principia, &c. independent, in a great mea fure, of the hyperbola. He then points out, in a feries of 24 problems, "what and how much is ftill wanting for the compleating of this art, both in theory and practice.'

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Befide the refiftance which is made to the fuperficies of bodies by mediums through which they move, it was formerly imagined, that there exifts an æther, or very fubtile medium, which penetrates the interffices or pores of bodies, by means of which their internal parts are refifted. Sir Ifaac Newton brought this opinion to the teft of experiment, and found, that the refiftance fuppofed to refult from this caufe was very inconfiderable and our Author apprehends that, if he had repeated the experiment, he must have proved that no fuch æther exifted.

What was the opinion of Sir Ifaac Newton on this fubject, it is not eafy to determine; but it has been prefumed, from fome of his pofthumous writings, that he was not an abfolute unbeliever with refpect to the exiftence of fuch a medium.

Mr.

Mr. G. apprehends otherwife, and takes pains to expose the notion which fome have advanced as altogether unjustifiable. Leaving however this difputable fact in an undecided state, we fhall proceed to select fome obfervations of our Author on this fubject. This æther (he fays) has been imagined to be the caufe of gravitation, cohefion, magnetifm, repulfion, sensation, and of almost all the phænomena in nature. It has been conceived of as growing always denfer, as you recede from the bodies of the fun and planets. But, if the motion of the earth towards the fun be occafioned by the impulfes of a medium growing always denfer as you recede from that luminary, and its elaftic force increase with its denfity, like that of the air, ought not thofe impulfes to be always diminishing as you go nearer to the fun? But they must be always increafing to produce gravitation. Wherefore the hypothefis is abfurd. In like manner, if this æther is rarer in, and at the planets, than at fome distance from them, ought not the acceleration of bodies towards the earth to be always diminishing, instead of increasing? This, however, we know, is not the cafe.

It will move in two oppofite directions, in impelling the earth and moon towards their common center; in two other oppofite directions, in impelling the fun and earth towards their common center; in two other oppofite directions, in impelling the fun and each of the other planets towards their common centers, refpectively. And, as the pofition of the earth and moon is infinitely varied in the courfe of one revolution round the fun, does not this fluid move in diametrically oppofite directions across the direction of its motion towards that body, and in an infinite variety of ways and pofitions? Is not the fame obfervation applicable to Jupiter and his fatellites, to Saturn and his fatellites, and to all the bodies in the folar fyftem, fince they mutually gravitate towards one another? What an infinite variety of oppofite motions, then, must this æther dance with through the univerfe? That fuch an infinite diverfity of oppofite motions in the waves or pulfes of this fluid fhould exist, is altogether impoffible. Would they not by encountering destroy one another, and reduce the whole fluid to an equilibrium or ftate of rest?

Befides, as foon as the common center of the earth and moon has changed its pofition in abfolute space, and come to fome other point, the pulfes or waves of this fluid muft proceed in oppofite directions towards that point, and impel thefe bodies towards the fame. And as these bodies are connected with the other bodies in the fyftem, in all pofitions they may happen to be in, we fhall have etherial whirlpools in almost every point of space bounding the folar fyftem.—

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The force of gravity, with which any body tends towards another, depends not only on its diftance from, but alfo on the quantity of matter in, that other body. How then is the elaftic force of this medium, in impelling bodies towards one another, varied with their quantities of matter?

Befides, if fuch a fluid be the cause of gravitation, how can we be certain of the truth of this propofition, that the fpecific gravities of bodies, or their weights under equal bulks, are proportional to their quantities of matter. For how can the folid particles of this fluid equally impel the folid internal particles of bodies refpectively, in the direction of gravity? This cannot be fuppofed by the advocates for fuch an æther, without maintaining the penetration of impenetrable substances, or fhowing matter not to be impenetrable, which has never yet been done, and is altogether inconfiftent with the Newtonian idea of it.'-The Author adds feveral other obfervations to the fame purpofe; for which we must refer to the book itself.

The fecond part of this treatife, containing a new method of deriving the theory of projectiles in vacuo from the properties of the fquare and rhombus, is purely mathematical, and admits of no abridgment or extract. It will be fufficient to observe, that the principles of the art of gunnery are hereby rendered intelligible to those who have no acquaintance with the C-nic Sections.

ART. VI. An Anfwer to the Declaration of the American Congrefs. 8vo. 2 S. Cadell, &c. 1776.

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VERY attentive and difpaffionate reader of the Declaration of Independency, iffued by the American Congress in July laft, must have obferved, that many of the articles of impeachment there exhibited against his Majefty's adminiftration of government, have more the appearance of frivolous cavil, and peevish invective, than of the manly resentment of a people fuffering under the iron hand of oppreffion, bereft of their conftitutional liberties, plundered of their property, or deprived of the natural rights of mankind.-Grievances of this petty cat could not fail of weakening the force and effect of thofe objections which feem to be of weightier substance, and higher import; as, in every kind of argument, one indefenfible pofition, or ill-founded fact, always creates a diftruft of the moft irrefragable truths advanced in fupport of the same caufe: and, like poltroons in an army, only ftand in the way of good foldiers, who would have been victorious without them.

But the Author of the prefent tract does not condefcend to take advantage of every opening in the weaker parts of the Declaration in queftion. He boldly undertakes to demolish the REV. Nov. 1776.

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whole work, by fucceffive attacks on every distinct article of which it confifts; at the fame time, however, appearing to make very light of his own enterprize: for he fcruples not to declare, that of the whole lift of charges, fo confidently urged against his Majefty, each feems to be diftinguished by its own peculiar abfurdity.So that he leaves little room for pluming himself on the victory that is fo eafily to be gained.

Confident, however, as this champion is, and exulting in his own ftrength, or, rather, in the weakness of his adversary, we must do him the juftice to obferve, that the abilities which he poffeffes, are well adapted to the tafk he has undertaken. He is amply furnished, with respect to every kind of neceffary information, relative to the feveral points in debate; his rea foning is clofe, his language clear, and his ftyle acute and animated; but we cannot approve his angry and contemptuous manner of treating his antagonists. He feems to think no epithets too harsh for the Americans. Eut what has the calling of ill names to do with argument? What does railing prove? Nothing but a want of candour and moderation in the perfon who makes use of fuch weapons. Will the verbal abuse of two or three millions of difcontented people, remove their discomtents, or convince them that their grievances are imaginary? That they believe them real, will admit of no doubt when we confider that men can give no ftronger proof of their fincerity in any caufe, than the hazarding their lives and fortunes in its defence. If the Americans have fet us an example of intemperate and unbecoming fpeech, it is, furely, beneath us to follow it. It is not a tongue-doughty fcolding-bout, not a war of words, in which we are unhappily engaged.

With regard to the neglect fhewn by Government to the Declaration of the Congrefs, it is jaftly remarked, by our Author himfelf, that ill would it become the dignity of an infulted Sovereign to defcend to altercation with revolted fubjects-This would be to recognise that equality and independence, to which fubjects, perfifting in revolt, cannot fail to pretend.—I would it become the policy of an enlightened Sovereign to appeal to other ftates on matters relating to his own internal government. This would be to recognise the right of other states to interfere in matters, from which all foreign interpofition fhould for ever be precluded.

To thefe confiderations it is, we must attribute the neglect with which the Declaration of the American Congress has been treated by the Government of Great Britain. Eafy as it were, and fit as it may be, to refute the calumnies contained in that audacious paper, it could not be expected that his Majefty or Minifters fhould condefcend to give it any anfwer.

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• But that answer, which neither a sense of dignity, nor principles of policy, will allow the Sovereign to give, may yet be furnished by the zeal of any well-affected fubject.'

Our loyal and spirited Author has, accordingly, fitted out his privateer, to cruize against these audacious' revolters; and in good feafon has he launched her ;-at the critical juncture when his Majesty opened the prefent feffion of Parliament with full affurance that his faithful Commons will readily and cheer"fully grant him fuch fupplies as the maintenance of the "crown, &c. will be found to require." SPEECH from the THRONE, Oc. 30.

With becoming zeal, therefore, does our Author declare, how happy he fhould be, could he fuggeft new motives to his fellow-fubjects of Great Britain, for fubmitting with cheerfulness to the burdens which must be borne, for concurring with zeal in the measures which must be adopted, to effectuate this important object.

Happy fhould I be, continues he, could I contribute to efface any ftain, which the falfe accufations of the rebellious Congress, may have thrown on the character of a Prince, fo justly entitled to the love of his fubjects, and the esteem of foreign nations.

Happy fhould I be, were it poffible to induce this deluded people to liften to the voice of reason; to abandon a set of men who are making them filts to their own private ambition; to return to their former confidence in the King and his Parliament, and like the Romans, when they threw off the yoke of the Decemvirs :-"Inde libertatis captare aurám, unde fervitutem timendo Rempublicam in eum ftatum perduxere."

As a fpecimen of the manner, and the fuccefs, with which this well-appointed champion encounters the rebellious Congrefs' we fhall give his answer to two of the charges which they have prefumed to bring against his Majefty; and thefe articles we have felected, becaufe they relate to circumftances which have not been fo generally canvaffed as moft of the other topics bere brought under review.

ARTICLE XXVII. "He has excited domeftic infurrections among us; and has endeavoured to bring on the inhabitants of our frontiers the merciless Indian Savages, whofe known rule of warfare is an undiftinguished destruction of all ages, fexes, and conditions."

ANSWER.

The article now before us confifts of two charges, each of which demands a feparate and diflinct confideration. The one is, that his Majefty" has excited domeftic infurrections among them;" the other" that he has endeavoured to bring on the inhabitants of "their frontiers the merciless Indian Savages."

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