Times. |it| Dist. Heliocen- Helio- | Geocen- Geocen- |Product off and earth. Nov. 9,34 1,25 0,88 1,13 11 29 24 32 30 10 28 22 56 36 1975 TO 15 50 53 1,51 10 8 36 46 47 1,10 9 29 18 27 45 0,46 2 7S 0,25 " Jan. I, 0,45 0,59 8N 0,26 9 14 31 9 12 58 3 23 25 17 17N0 2.50 13 the comet equally visible fhould be as the product of its distances from the fun and earth, and the product of the numbers above mentioned 0,986 and 1,37 is 1,15, we fhall have the following analogy to fird the aperture of a refracting telefcope fufficient to show the comet as it appeared to Hevelius. As 1,35: 1,65 inch :: 9:11 inches, fo is the product of distances from the fun and earth to the diameter of the aperture required in inches." "The last observation made by Hevelius on the comet in 1661 was when its distance from the earth was 0,986, and from the fun 1,37, with what he calls a very long and good telescope; at which time it appeared faint and fmall with it, though ftill fufficiently vifible. Let us fuppofe this to have been a telefeope of 9 feet focal length, with an aperture of 1,65 inch; then, becaufe the diameter of the aperture of a telefcope fufficient to render PRIMARY NOTIONS of the MATTER of FIRE. [From Dr. HIGGINS'S EXPERIMENTS and OBSERVATIONS on Subjects of CHEMICAL PHILOSOPHY.] ceffes are the mixtures producing heat, the abforptions of divers cold elaftic fluids caufing heat, vitriolizations, incalafcence of pyrophori, refpiration, putrefaction, fermentation, and combuftion. In all these, the matter of fire, fo foon as it is liberated, is found by its peculiar effects, and the menfurable decrease of heat at increased distances from the fource of emillion, to move excentrically from that fource, and to decrease in density. But as this happens, whether the extrication of it be attended with illumination or not, it indicates nothing that is confitent with the tenor of nature, or that may be fuggefled by analogy, except that the parts of the matter of fire repel each other, although they certainly are attracted by other kinds of matter. This repellant property is equally apparent in every inftance of the formation of elastic fluids from aggregate bodies; and especially when this is done by mere ignition. But as thefe inftances afford another inference of equal ufe, I fhall fubjoin them to the following notion. “3, The matter of fire, by virtue of the repulfion fufifting between its bomogeneal parts, and of their attrac tions to the parts of other matter, is the cause of the elasticity of aeriform fluids. "This notion is neceffary to the folution of the phenomena, and is fupported by direct evidence, of which the following part will be fufficient. "Oils, refins, vegetable acids, charcoal, and divers other bodies, are almost totally convertible into fixable air and inflammable air by fire. Nitrous acid may be decompofed and converted, in part, into empyreal air, in the remainder into phlogistic or nitrous air, by the agency of fire. The whole fubitance of folid nitrous ammoniac is convertible into fluids permanently elaftic, by the mere action of fire. From the folid aggregation in manganefe and other metallic calxes, and in divers falts, the grofs matter of empyreal air may be propelled, to form an elastic fluid by fire; fo may that of denfe inflammable air from coak and divers hard bodies; that of fixable air from tony concretes; that of alkaline air from ivory, Pruffian blue, and microcofmic falt; that of vitriolic, or of marine, or of hepatic air, from divers folid, faline, or fulphureous compounds. All this is done by fire; and being beft effected in veffels that are impervious to every other known matter, amounts to a fatisfactory proof that the matter of fire is the only acceffary and agent in the converfion of folid bodies into elaftic fluids, and in the maintenance of their elasticity. "The electric matter is not to be mentioned in objection, until it is proved that it does not itself confit of the matter of fire, in a certain modification of it, depending on the repultive property, and the relations to grofs matter, which we are now defcribing. "Seeing this extenfive agency of the fiery matter; that we can not only trace it into the subjects which thus become permanently elaftic, but that it gives a temporary elasticity to vapours and fublimates ; feeing that thefe refume their age gregation as faft as it escapes from them; that its union in the fluids, to which it gives permanent elasticity, may be further proved by the extrication of it from every one of them; and that, in thefe libera tions of it which are daily experienced, in the abforptions of elastie fluids, in combinations, and in combustions of them, the emillion is is fo copious as to remove all doubt of their having held it in great quantity, united with their refpective feparated parts, and restrained during that union from acting like liberated fire; obferving alfo, that as fast as the fire is liberated or excluded, the distant groffer parts of elaftic fluids rufh together or into other bodies; as when empyreal and nitrous air makes nitrous acid, or empyreal and light inflammable air make water which cools to folid ice, or marine and alkaline air make fal ammmoniac; or as when acid or alkaline airs rufh into wa ter, or empyreal air into phosphorus; we cannot now hefitate in admitting that the groffer parts of elaftic fluids, as well as thofe of vapour, are made to recede from each other contrary to their inherent and inceffant attractive powers, by vir tue of their refpective charges of the repellent matter of fire, and confequently by the repulfion of the parts of fire to each other. "This is an evident confequence of the former notions, and the prevalence of the repulfive over the attractive forces; and the terreftrial atmosphere, in which the denfity is inverfely as the fquares of the distances from the earth, fhews that it is the natural and neceffary effect of fuch forces, to form the charges of fiery matter which the particles engage, into the defcribed atmospheres. The further evidence of the truth of this notion arifes from phenomena, which I am prefently to confider and ex plain, and which are not inexpli cable by any other condition or agency of the matter of fire, that has been hitherto fuggefled. "5. The repulfion of the homoge neal parts of the matter of fire, limits the quantity that can be engaged by bodies, and tends to diffuse the der equably in space. remain "This notion needs no illuftration. "6. The matter of fire limits the quantities, in which aeriform fluids, and bodies containing it, can combine chemically. "In the converfion of folid bodies into elastic fluids, we perceive the repulfive forces of the matter of fire refifting and overpowering the reciprocal attractions of the groffer parts; and in mixtures of empyreal and inflammable air, and in divers other mixed airs, we fee this matter refifting the attractions which tend frongly to the chemical combination of the heterogeneal gravitating particles. "In fuch inftances it is manifest that the fum of the repulfive forces, exceeds that of the attractive. "When aeriform fluids condense each other, or are concentrated and aggregated by bodies, it is equally evident that the attractive forces, although refifted by the repulfive, are prevalent. 6. Thefe, and divers other phenomena fhew, that the natural power, whether attractive or repul five, of each part of matter, is limitted; and therefore the fum of thefe powers which any body can exert in regard to another, is by a law of nature as the number of its active parts, or in other words, as its quantity of matter. "In confequence of this law, the fum of the repulfive forces, which relift the approximation of the gravitating parts of an elaftic fluid, and their union with those of a bo dy dy which alfo holds fome of the matter of fire, is as the quantity of that fluid; and no more than a determinate portion of it can be aggregated and combined in the body whole quantity of matter and attractive powers are limited. "By the fame law it is determined that elastic fluids fhall unite with each other in limited proportions only, to form denfer fluids or folid bodies, and that the fuperfluous quanti ties shall remainelallic and unaltered. "As the matter of fire is manifeftly the agent which refifts the coalefcence and union of attractive particles in thefe cafes; and as the fame matter demonftrably exifts in all bodies that unite only in limited propor tions, we mult afcribe to this only competent and manifest agent, all those limitations which we experi. ence, in regard to the proportions in which bodies can be chemically united, and which we briefly exprefs by the word faturation. APPLICATIONS of the FOREGOING NOTIONS. [From the fame Work.] S the limits of this effay do not permit me to make extenfive applications of the forego. ing notions, I fhall endeavour, in the expreffion of a few, in tis and the following section to fuggeft every thing that feems neceflary towards explaining the most intricate phenomena of the matter of fire. "In regard to the apyrous bodies, fuch as the pure earthy fubftances, I would infer from thefe notions that they chiefly confift of parts which do not attract the matter of fire with forces fufficient to caufe a difunion of them, and an interpofition of this matter in fuch quantity as to induce foftnefs or fluidity. lent attractions which tend to reunite their grofs parts; but that they receive and tranfinit the mat. ter which caufes heat, more freely, and they retain it longer, than the former can in fimilar circumstances, by reafon of the stronger attractions. "The bodies, which, like oils or water, form elafic vapour, when duly charged with the matter of fire, confit chiefly of parts which attract it with forces fill greater, and fufficient to compel atmospheres around the diftant molecules; but yet not fufficient to retain these atmofpheres after the influx of fire ceafes, and in oppofition to the mu dal attractions of their central molecules, and the tendency of the fiery matter to diffufe itself equably in the neighbouring spaces. As the thermometer fhews no more than the relative quantities of free matter of fire in bodies, these lately mentioned require a greater quautity of the fiery matter than the former, before they exhibit an equal temperature by the thermome ter, for the reafon already mentioned. H It "It is alfo by virtue of this fuperior attraction to the fiery matter, that ice, relin, fats, and other vapourable bodies, become fluid by moderate incalefcence, but not before they have received a great quantity of fire; and that they refpectively evaporate with lefs ignition or incalefcence, in veffels which avert the preffure of the aerial atmofphere, than where that, or any equivalent compreffion, confpires with their aggregate attractions, to refift the influx of fire, and the difjunction of their parts. Thus water, or fpirit, moderately heated, and placed in the receiver of an air-pump, boils when a part of the air which compreffes it is drawn out, and ceafes as often as the preffure is reflored. - "Still fronger attractions of the matter of fire, comparatively with the forces which tend to the exclufion of it, are feen in ethereal oils and ethers for their vapours cannot be condenfed without the aid of compreffion; and when they are thus condenfed and aggregated, their molecules, by attracting fiery matter and compelling it into atmofpheres, with forces fuperior to thofe with which they attract each other, are made to recede, and form aeriform fluids, in the lowest temperatures, fo foon as the preflure of the atmofphere is averted. That the expanfion of fuch ethereal fluids into the aerial form, in the exhaufted receiver of an air-pump, is owing to the tendency of their molecules, to attract the matter of fire and to form atmofpheres of it around them feverally, and that it is not effected by any other agency, is apparent from the concomitant phenomenon of cold: for as fast as they affume the aerial form, they engage and fix the free fiery matter which belong. ed to the fpaces into which they expand; and this privation or deficiency of difengaged fiery matter, is what we call cold. "The bodies which by ignition may be partially or totally converted, even under the atmofpheric preffure, into fluids permanently elaftic, fhew the kinds of matter by whi h tha of fire is attracted in the fupreme degree. "For the elasticity which fubfifts under immenfe preffure, argues a ftronger attraction of the particles to their respective repellent atmospheres, than that which we laft noticed; but that this ftronger at traction compels denfer and deeper atmospheres, may not only be argued a priori, but is experimen ta ly demonftrable by the bulk, which in elaftic fluids is the meafure of the atmospheres, compared with the gravity, which is the meaf of the grofs particles; and it is alfo apparent in the extraor dinary quantity of the fiery matter that efcapes in the inftant of the aggregation of thefe elaftic fluids, or rather of their particles, to form conliftent bodies; as when empyreal air is rapidly imbibed by phofphorus, pyrophorus, hepar fulphuris, or iron filings and fulphur; when alkaline air, and divers acid airs, are abforbed by water, or when they condenfe each other; or when the rare inflammable air and empyre air make water, and exclude their matter of fire. "From all this it may be inferred, that in any future table of the affinities of the matter of fire, pure phlogifon ought to rank above every other kind of matter; instead of being omitted, as it is in Bergpan's tables, or fuppofed to have repugnance or apathy to the mat ter of fire, as Dr. Crawford formerly conjectured. But when this precedence |