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oxygen gas, is inc able of Supporting combustion Or vospi ration, is scarcob sensibου absorbed by water, and is notcombusti ble in the strici sense of the term ; DP although it, combines With oxygen, the combination is not rapid ; it domnot, after it has commenced, proceed of itself, and it is notattended with any sensibie omission of heat or light.Νitrogeia gas forins nearly four fifths of atmospheric ait, ille rema ining fifth being oxygen gas. In more inimia iticombination With oxygen, and in that pi postion in whichthey are mutuatly saturaled, it forins a Very po ea ut acid, the nitric acid ; and in lower demees of ο genation it sortiis compound gases which have no acid powers. With hydrotagon it fornis ammonia, one of the aikalis ; it exisis in sonae vegetable substances, and is a constituent principie of near init the varioties of animal mattex. This substance must stillhe regarded as simple, DP although, Dona Some resear OS connected with the action os pota SSium on ammonia, Conje iuros hia heon formed with regard to ille composition os nitrogeia, these Were always doubilat, and it notu appears wero
ATMospΗERIc AIR, of which oxygen and nitrogen are ille essentiat constituent puris, has mereb the aggregate prope ties of these two gases, theiae combination being so flicti thalno nCw po vers are acipitred fimm it ; anil, as the oxygen is the more en orgetic ingi dient, the chemicat ageiacies of this
.r depend chiosty on the operation of this principio. It
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bined, it is the liotest os ali tho elastic fluids, and the liotest
The produci os iis combustion is water, M sicli is there reconsidereii as a compound of it with oxymn. Combinedwith nitrogon, it forins ammonia : with the primary insana milles, Sulpturi', carbon, and phosphorus, it sorans compotrudguses :. it dissolves even Some of the metuis, and it is an abundant ingredient in vegetable and animal substanceS.II ATER, of which hydrogen is ille base, is a Substance CX- ire moly peculiar in iis chemicat relations. Iis power os combination is extensive, thero heing feri substances on whicli itdoes not aci, vith Whicli it does not combine ; yet in thegreater number of these combinutions no energetic action is lisplayed ; it in generat scarcoly produces any alteration Ofproperties ; and heiace iis most important operation is tho. commvitica ting that stato os suidity to hodies V hicli is ne-eossary to their mutuat Chemicat actions. It is more pecu liarly tho solvea os ali saliuo substances, and of the grinter number of the eurilis ; and it dissolves many of the veget leund animal producis. I 'iun it commmaicateS OXmen, it pro- duces more important changes. Severat Os the metati are
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position at elevated temperatures, the elements of tho waterili contain enter into the composition of the producis ivlii biliose decompositions afford . There are three substances supposed to be simple, distin
giushed by the property of inflammability, and heiace named Simple Lissammabies, whicli exist as constituent principi
os a number of natural producis. These saee carbon, Sulphur, and phosphbrus. Some rescarches aspectae to fa Our the Con
CARBON. The ultimate base to Whicli the name of ca Boii ought to be appropriated is perhaps Stili imknown tous ; but there are severat substances of which it constitutes the M'eater pari, and in Whicli it appears to eris 1 in a statones ly puro. Wood charcoal in huming is aliuost entiaeelyconsumed, forming with the oxygen ivitii V hicli it combines a peculiar elastic suid, carbonic acid, and loavmg only a sinali residuum os earthy, saline, and metallic Substauces. As udiscriminuting appellation of the pure hin uuable matterwhicli thus combines M illi Oxygen, tiae te ira Carbon as ha-trodii ced, and it denoted iliores ore simply this mattor seceiroin the ollitu substances mixed M ith it in clivi coal, and l arently Dot essPntiat to iis constitution. ' It was astoris avds discovered, Iliat ille Di monil, which was known to bo a combusti ble hody, uisoriis in biuuiiug prccisely the fame produci as charcoul, and trunco thorcsore consistes of tho sumo inflammabio mutter. Distori ut opinions riore ad 'anccd Wii Iregarit to tho disserenco botri eon clini coal and di monil ; asthev combine in hurning illi the Samia proportion of ON geni
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OF THE GENERAL PRINCIPI Esaia afford precisely the fame produci, the disseretice appears to be mePely in aggregation ; charcuat in itS common State, Ilowevor, ulways Contains a portiou of hydrogeii, and it is doubi fui is it can bE onti ly Decii froin ii. In the substanconamed Plumbago, the carbonaceous base is imited with asinali quatitity of iron. It is to the inflammabie matteae common to est these substances, composing nearly the wh0le osthcla weight, and forming with oxygen a peculiar acid, that
the terna carbon is appropria ted. Carbon, besides existing as an clement in the compositionos many minorat substances, is an ab dant ingredient in the producis of the vegetable and animal systems. Not heingvolatile, it fornis tho principat pari of the residual in s when' these are decomposed by heat; und it is by this decomposition os vegetable matter, especialty of the wood os planis, that it is obis inod in the forni os charcoal. Mith oxygen, combined in different proportions, it fornis two elastic quids, carbonio oxide, and carbonio acid. Mith hydrogen und oxygen, in disserent proportions, it forins various iussammablegases. Axkohol, or pure ni dent spirit, Whicli is the productos tho sermontation os saccharine mattei, is a similar Com
carbon, hydrogeia, und oxygen, in Variolis proportions and modes of combination, appeara is constitute die principat varieties of vegetable matter. SULPisun is mund in natiure principalJy as a constituent
enters into the composition os a Diuuber of snline and earthy
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an clastic suid, ptingent and sui cating, Sulphurous acid. ith a largo proportion of OXygen, it forins a denso inodotous liquid actis, sulphiuic acid. With hydrogen, it sortiis ainiustatum te gas, sulphurei ted hydrogeii, whicli exisis in nature imminuating water in the sulphurous mi uerat Haters ;and this cumpo d, eithur alone, or With an additional proportion os hydrogeu, serining What is namia super ulphuret- ted hydrogeii, inters into combination with aikalis, earilis, and metallic Oxides, forming severat important pharmaceutic
preparations. L. tb, Sulphire extris as a ConStituent part os
animal Substances : henoe sulphuretted hydrogeii is generaIlyevolvod in the decomposition of these heat or putrefaction : it has also been defected in the composition Os a se vegetabies. In iis common state, sulphur appeam to containa portion os hydrogen. PROSPHORUs exigis chiessy as an ingredient os animal mat- ter. Combinia Min Oxygen, in the state or an Mid, it iam inters into the composition os severat of the producis of theminerat tangilom. It is os a sost consistence like wm, Semia transparent, and of a White or yeliora isti colour; it is soli tib insummabies that it burias spontaneoi ly When eX Sed to the air. It combines With two prolaortions of oxygen, sorm-
mnia in minute quantities of hydrogen and oxygen, hut si eis no conclusive proos that this is the case. The class of METALs is an extensive one, the Si Stans CSto whicli this immo is appropriated heing numerous, and thonumber being stili Arther augmentia, is the bases of the al-kUis and cartiis are to he admittod into the class. The phy-
ical properties, chalucteristic of the metias, are opacid ,
eat lustre, densio, ductili , avit malle isty. These aie
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OF THE GENERAL PRINCIPI ES posscssed in differoni do eos by the disserent metuis, und ilthe bases of the athalis and eartiis aru to he admitted as me istis, the property of density cannot be considerod aes distinc live, as Some os these are even lighted than wator. IVithregarii to chemicat properties, the meta is a re si ibie, in generat not volatile excepi ut very intense heatS ; they are cap te os combining with oxygen, With hydrogeia, Sulphur, carbon, and phosphorus, with euch otheir, and when Oxidaledffey unite with acids, urialis, and earilis. Os these combinations, that with Oxygen is the most important ; and in relation to the object of this ouiline, theonly one requiring any farther observations. This combina- fion is effected in various modes. When heated in contactivitii the ala, they attraci iis oxygen: is the temperature hevery hi dy elevate I, as in that pro taced in the mlvanio circuit, they display during this oxidation the plienomena os
iures, And est of them cuia be oxidated by acitis, the acideither directb. impuriing oxygen to the metat, or enabling itio attraci this principie from the water Whicli is present. The compoundes of metals with oxygen belong in generalto the ordor of oxides. They are destituto of the physical
In combining With oxygen, different metuis vilite ivitii Vei different quantitios of it. Fach of them combines too with different proportious os oxygen, giving rise to the productionfroni the Sume metui os oxidias having dimovevi proportios :
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nre osten algo extremoly dissimilar, a circumstance of muchimportance, as is to he aster variis pianted oui, with 1 enfrdio the pharmacelitical processes on the metales.
combine u illi the oxide that is formed. A A the fame meta is cap te of existing in different states of oxidation, so bycombining in these states With the fame acid, it fornas very different compounds ; and these componitas are sarther dive sisted by the different proportions of acita combinod in them. Metals are rendered active ou the living system, principutly by being thus combinud with ovgen, or farther Combinedivitii aci I. In their metallic state, they soldom produce any sensibie effeci; and any effect they do produce appears to ise hom thoir heing chemicatly acted on by the gastrie fluids. When Oxidaled, they beeome more active and stili more So When the Oxide is combinod with u acidia Andeven the degree of OXymnation consideras bly influences their wers; so that froni the Same metat preparations of ve
different dentes of medicinat activitymay be obtainta, thoughail agi vicing in the Lind of action they exeri. It would be sordign to the object of this S tch to suo rho description of the individual metuis: it is sussicient tohave stared with rogard to them theso generat facis. Fe
of them exist as common ingredionis in the composition os natural substances, with the exception Of ii R. I lic cisses of EARTHs compriZ a se SuhStanCeS, POSSUS
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OP THE GENERAL PRINCIPI ESang certain common properties, whicli are the ultima te principies of the various compounds, not metallic or instasiam ul)lc, whicli occur in the inhierat tangdom. Au analogy had ost Cnheen observed to exist belween these substances and metallicoxides, whicli ted even to the conjecim e that thoy are os similar ConStitution, or consist os metallic haeses combined withoXymen. Their decomposition has accordin y been ei sected by the application of galvanism; thoy are com undA or CCP-ta in basos ivith oxygon, and these bases posseSS general ΡΠ perties, so nearly allied to those of metuis, iis to bo susicioni
perhaps to justisy the placing them in that class, yet stili solar different as to afford Some reasou sor Pegarding them atteast as a peculiar Orderis
cxicut, and ad of them may be sused by very intenso hestis. The principat cartiis stre Silex, Argil, Magnesia, Lime,
Eurytes, and Stronides o Tu con, Glucine, aud Itiria, have more dotibilat clatuis to be ranked in this class, or exist in Auch minute quantities as to be comparatived visimport: vit. SILEX is an abundant ingredient, not only in initierat sub- Srancos, but is frecruently contained in vegetable producis, and fornas part of the carthy residuum of tho P decomposition.
It is tu teless, ncarly infusible aud insolubie in xvater, and is peculiarly disthiguished by iis ineriness, and comparatively limited range os combination ; among ille acides it combines oub With the fluoric, and even scarcely neutrali es ita pro-
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perties. It is dissolved by the fixed athalis, and it unitos bVfusion ivitii them, and with the other eartiis, and the metaliatio orides.
ARGIL is insipid, sost to the touch, infusibie, insolubie in vater, und particularly distinguished by serining u4th that
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tained, iliough not perhaps persectly insulated ; it has themetallic lustre, and is hi ly insanam able.
BARYΤΕs sui passes lime in enero os chemicat action.
transparent prismatic crystals. Iis solution changes the Vegetable colours to a green. This earili combines ivitii theaci is, and either froni the superior strength of iis attraction or the influeuce os cohesiou on iis combinations, it decomposes the meater number of the Salis of the other cartiis and the aikalis. It exeris amnities to the other earuis, and
to sulphur and phosphorus.. Os est the substances of th1s class, it is the one Whicli acts most powerfully on ille livingsystem. Even in sinali quantities, it occasiones impleasant Sympioins, and iis preparations prove p0is ous to animais. Froni this quality, and Dum another, the great Specisic gravity os severat of iis saline combinations, pateticularly the native sulphate and carbonate, barytes WaS Often more peculiarly supposed to be of a metallio natu e. Iis decomposition has been effected by the application of gulvanism, and a baseobtainod Dona it, Mi a metallic appearance, having the colou of silver, considerat,b heavier than water, fusibie at a heatbelow reditess, not volatile, inflammabie, and Poproducing bai Utes When combincil With oxygon.
blance to barytes in many of iis properties. Like it, it has