1753. Reply to Mr. HORNE about a PLENUM, &c. 281 To the AUTHOR of the LONDON' SIR, T B HE learned Mr. Horne (fee p. 18o.) having been fo kind as to take notice of, and anfwer the questions I flated in your Magazine for March last, p. 119, I hope you will allow me to A return him my thanks, which every gentleman deferves who endeavours to fatisfy the fcruples of another, tho' he may not entirely fucceed in the attempt. I confefs, I did not fuppofe, that in p. 6, of his ingenious performance, he meant to define rarer to be, confifting of particles of a smaller fixe; because, according to the meaning I have always put upon the word rarer, one fort of fluid may be rarer than another, and yet confift of particles of a larger fize; and if the constituent particles of one fluid, or any other fort of matter, be fmaller than the conftituent particles of another fluid, I cannot look upon them to be the fame fort of fluid They must be two different forts, even tho' mankind should give them the fame name; and how the conftituent particles of a fluid, or any other fort of matter, can of themfelves become of a fmaller or larger fize, I cannot con-` ceive; for friction or internal motion never alters the conftituent parts of any fort of matter, but only feparates thofe parts which before adhered together: Nor D can I conceive, why a fluid of large conftituent particles should push hard against a fluid of fmall conftituent particles, if there be no interftitial vacuity in either for if rarer be defined to be, confifting of particles of a smaller fixe, denfer must be defined to be, confifting of particles of a larger fize, and both must be fuppofed to confift of fquare or cubical conftituent E particles, which is contrary to the fuppofed nature of fluids, whofe conftituent parts are generally fuppofed to be fpherical; and if they are, there must be an infinite number of interstitial vacuities, let their conftituent parts be never fo fmall. question we cannot easily refolve, becaufe the constituent parts of fome forts of matter may be endued with a repulfive force, and confequently may without contact act upon one another, and upon all parts of matter that come within the fphere of their repulfion. The conftituent parts of air feem to be endued with this repulfive force, which is the reason that air may be vaftly compreffed by a compreffive power that is fuperior to its power of repulfion; whereas, tho' water may be rarified, it cannot by any human force be compreffed, or made to take up lefs room than it does in its natural state; and yet there must be an infinite number of interftitial vacuities in water, as muft be allowed, because the rays of light find an easy paffage, and becaufe water has always a certain quantity of air incorporated with it; confequently, thofe vacuities that are in water cannot be faid to be abfolute; but fill there must be interstitial vacuities between the conftituent parCticles of that air and light, which are in the vacuities between the constituent particles of water; and thus we muft either admit of abfolute interftitial vacuities in nature, or proceed in infinitum, by fuppofing an infinite feries of different forts of fluids, every one of which confifts of parts of a lefs fize than the former; which is a fuppofition not at all neceffary for the effects we fee produced by matter; for no one fuppofes, that the air or light that are in the vacuities of water contribute any way towards producing those effects that are produced by a stream of water; nor is it fuppofed, that the light which is in the vacuities of air contribute any way towards producing thofe effects that are produced by a stream of air, which we call wind, or a hurricane: And tho' that fubtle medium or fluid we call light, may have an infinite number of interftitial vacuities, tho' its conftituent parts may be indued with a repulfive force, fo as to be always in their natural ftate at a certain diftance from one another, yet it may produce all the effects we fee produced by it; confequently, for the production of thefe, or any other effects, there is no neceffity for fuppofing an univerfal abfolute plenum, without fo much. as the leaft interAitial vacuity. But indeed, if we admit thefe defini- F tions, and infift that there are no interftitial vacuities in the universe, we should banish the words rarity and density out of our language with refpect to matter in. general; for the matter in an exhausted receiver would be as denfe, as the matter in the fame receiver when full of gold; which no man can admit, who means to exprefs by the terms rarity and density, thofe ideas to which they have always hitherto been applied in our language. Whether fome forts of matter may not produce an effect without contaâ, is a June, 1753. G That there is in nature a fluid much more fubtle than air, is very certain: That this fluid is the caufe of light, of heat, &c. is likewife very certain, therefore, for diftinction's fake, I fhall call it æther; and it is probable, that by expe riments in electricity, we may difcover much more of its nature than has hitherto been known: But let its conflituent pa tieles ticles be never fo fmall, there muft be vacuities in nature; for let those parts be of what figure you will, they cannot abfolutely fill up that vacuity which we must fuppofe to be between three fpherical particles of air or water; and if we fuppofe them alfo to be fpherical, there must be an infinite number of vacuities between themselves, unless we fuppofe, as I have faid, another fort of fluid ftill more fubtle to fill up thofe vacuities, and fo in infi mitum. Now that this fluid, which I have called æther, not only may, but must be rarer or denfer in fome parts of space than in others, is certain from the diffe Subftance of bis Majefty's SPEECH at the rent degives of light and heat, which we BF feafon of the year was to far advan perceive; that is to fay, that its confti- From hence I muft fuppofe, that the electrical fream, the farther it moves from the electrified body, becomes not only the lefs rapid, but the more rare, that is to fay, its parts not only lose their motion by degrees, but become farther diftant from one another; and if my learned friend defines denfer to be, confifting of particles of a larger fixe, I thould be glad to know how the conftituent particles of the electrical stream come to encrease their fize gradually as they move off from the electrified body. Upon the whole, whether there be in any part of infinite space a cubical inch of abfolute vacuum, is a question we cannot refolve; but that there must be an Infinite number of interftitial vacuities, is, I think, evident from the nature of things; for tho' matter be divifible in infi. mitum, we must come to constituent parts or particles before we can form any idea of matter; and if thofe conflituent par E F ced, and the bufinefs before them fo entirely finished, that it was necessary to put an end to this feffion of parliament : That the zeal which they had shewn for his perfon and government in all their proceedings, called for his fincere thanks; and that the care and affiduity they had exerted, in making fuch provifions as might advance the commerce of his fubjects; fupply and extend their manufactures, and put a stop to fome diforders that required reformation; were no less agreeable to him, than they were proofs of their prudence, in laying hold of this time of tranquillity to make domestick improvements. That the state of foreign affairs had received no material alteration fince their meeting; and that they might depend on his fteadily purfuing the fame principles and ends, which he then declared to them: That to preferve the peace; to confult the real profperity of his people and, at the fame time, to affert and maintain the honour and just rights of his crown and kingdoms; were the fixed objects of all his measures. Then he tells the commons, that in granting the fupplies for the current year, they had equally fhewn their concern for the publick fervice, and their regard to the eafe of their fellow fubjects. He thanks them for both; as well as for providing with fo much forefight, for the future augmentation of the finking fund. Then he concludes with these words to both houses: "I have nothing to defire of you, but what I am perfuaded you with for yourselves. Do your utmost endeavours in your feveral countries, to promote the true intereft and happinefs of my people; to propagate industry; and to preferve good order and regularity amongst them; make them fenfible of the bleffings they enjoy; and, by thefe means, the quiet and fecurity of my government will be best established." H 1753. A QUESTION concerning the late Jews ACT. 283 To the AUTHOR of the LONDON SIR, PON reading the A to permit Per Ufons profeffing the Jewish Religion to be B naturalized by Parliament, a doubt has oc- A curred to me, whether any Jew can be naturalized by parliament by the act as it now ftands, and my reafon for doubting is this: Every person to be naturalized is to take the oaths to the government as prescribed by act of parliament, one of which is that we call the oath of abjuration. Now this oath, as prescribed by act of parliament, concludes with thefe words," and I do make this recognition, acknowledgment, abjuration, renunciation and promife, heartily, willingly and truly, upon the true faith of a Chriftian *." This being the form of the oath prefcribed by act of parliament, I am apt to think, that no court of juftice, nor either houfe of parliament, can difpenfe with or C alter thefe words without an act of parliament for that purpose; because in the act for explaining and amending the famous act of the laft reign, vulgarly called, The fwearing Act, there is an exprefs claufe for difpenfing with these words, when any Jew prefented himself to take the oath of abjuration in purfuance of the faid act, or the faid fwearing act +; and because there is a like difpenfing claufe in favour of Jews, in the act for naturalizing fuch foreign protestants as were then fettled, or should afterwards fettle in our American colonies 1. From the parliament's being so careful at both these times to provide for the Jews by an exprefs claufe, it is evident, that no inferior court of juftice can difpenfe with or alter thefe words when a Jew prefents himself to take this oath, therefore my only doubt is, whether either houfe of parliament can do fo, without the authority of a previous act of parliament for the purpofe; for if neither house can, it is certain that no perfon profeffing the Jewish religion can be naturalized by parliament, notwithstanding this new act in their favour. As this is a queftion of fome importance, I hope Lome one of our learned lawyers will give us his thoughts upon it, and therefore muft beg the favour of you to infert this in your next Magazine. June 19, 1753. I am, &c. I To the PRINTER of the LONDON SIR. HE character of a gentleman I had D E F G manner : when alive, and whofe memory I revere Nn 2 T the 13 Geo. II, |