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Of tlie stndy of elementary chemistry in schools is to educate the mind by giving it the right kind of exercise in tlie use of its powers, I have therefore tried to make a, judicious selection of the most fundamental facts and principles of chemistry, and to present these in such a way tliat the student must constantly use his senses to discover facts, his reason in drawing correct inferences from the data he collects, and good English in expressing accurately what he sees and thinks.

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PREFACE. my was Ik an Ekimeiitary Chemistry, written in 1872, it for l)eginners, in ivhit'h the piupose to give a short c
PEEFACE. IV V PREFAOE. stndy of elementary chemistry in schools of to educate tlie is make can be done to it less All that work. plex and diificnlt mind by giving the right kind of exercise in the use of it tlie or the other, the mechanical is to make one lo for heghiners powers, its processes, predominate in our elementary course or the mental make I have therefore tried to judicious selection of the a, The mechanical of be? Then which shall it of instruction. most fundamental and and principles of chemistry, facts to no phenomena sense, for there will be one in course stands first, way must constantly present these in such a the student tliat apparatus is selected and arranged to exhibit to study until use his senses to discover reason in drawing correct facts, his hand, a wise selection of apparatus them But, on the other he inferences from the data and good English collects, in ex- by one who has not already and conditions cannot be made pressing accurately what he sees and thinks. some skill in tracing the relations of cause and effect, acquired know way how of hut one to teach a student I of experimental to acq^uire application the in experience and some mind habit- a real knowledge of nature, and that power to fix his the cultivate think we should to is, first methods. I — on things and events brought under hia own eye, and ually that we should observe exhaustively and to detect relations, direct him to the discovery of facts and principles for himself. mental more prominent than the mechanical in the make the The use of apparatus of course, indispensable the is, elementary study of chemistry. Accordingly: if phenomena thus to study student instead of descriptions In this courae of experiments the mechanical operations is phenomena, and the use of apparatus, by himself, is with- of Exactly what is to he are described in quite minute details. out doubt the method which most certain to stimulate and the meaning of it, is his is happen, but what to is done is told, mind Laboratory stndy for students to tlie gieafest activity. Exceptions to this plan will be found a time withheld. for rapidly growing in favor, but unfortunately, in high schouls which are simply means to is of processes in the description many where chemistry secure conditions, and in the statement of facts which may be taught, the difflculties in schools in is method are way thought Even But in general the phenomena bo of this the real. in to still needed for immediate use. be truly useful shoold these, chemistry to presented as a whioli hold the chemistry of substances or pi-ocesses are left lie study of phenomena, hy esperiments, instead of what some- page See, for example, 35, or for the student to discover. phenomena liody has said about in books. pages 85, 86. a course of experiments have therefore tried to construct I upon the many, much know industrial laid stress that i>y I is, suited to the use of the beginner, at his laboratory desk, and But value of an instrument-making course in chemistry. it of the teacher of beginners, where to the use for his class me that the study of chemistry not primarily to seems is to themselves seem work he out facilities for stuilents to for to mechanics, and that the use of tools and the po.ssession teacli of reach. am be better acquired in the indus- of mechanical ingenuity The study any subject by experiment combines two kinds of school or workshop, where these are the specific aims, trial mechanical and menial operations go hand of exercise; in than in the laboratory of the high school or academy, where On account experimental investigation com- hand. this a is the acquisition of knowledge for the sake of mental training is
: vn PREFACE. ,! PREFACE. VI jud.cous seleohon, hut have .vied to make a Home-itiade apparatus not to be de- the chief purpose. of experiments, is ,i,t ones well made and thoroughly in^hat a few typical he greatly respected, where nothing better can be spised, but lo Si would be useful than a larger number common more had, for miicli can be done with the most utensils, far studied^are study of a I mean by the thorough What and oyster-cans. But stu,lied in haste. such as lea-saiiccrs, bottles, fruit-jai's, treatment of a subject may be seen by In the work with good than do certainly heginncrs can f.w experiments Vietter facililies " Decomposition of mtnc " Substitution;' pp. 10-31 And much market in the : with poor ones. wliile there'is so Teferrin" to 141-145, " ailorides," pp, 02-95; or at once scientific and inexpensive, the student sliould whieh is acid," PP- be tanght to reach more accurate resulls tlian are otherwise such teacliers for when provided by better Additional work is Productive ingenuity and use of possible skill liy tlie it. undertake I to it. have time or talent classes as T,upils or must be founded on exact knowledge and clear thinking; they partake of the nature of research as would make such work Therefore cannot precede these. some question lo may A be given student as possible. much course has been selected Tlie apparatus called for in this two substances wh(^e own experiments, or be answered by his made appioved The which by, cheniists. from for, aiid is tliat results he is directed to investigate, or mutual reactions and pieces are neat, simple, easily put together, always in market, properties he is asked to study and report. a single body wliose (See Appen- good and as cheap as possible for scientific ^vork. the head of "Ex- work of tliis kind I have given under Some dix, Fig. 69.) examples, pp. 39, 82, 100.) (See, for ercises." A brief summary and most important of the principles facts laboratory stands research JText in value to research in the mental work, by which the student can chock follows the e :« pel- i how to make all means teach the student In this sunmiary By be found the and correct will his results. in the library. apparatus au
; vm PREFACE. have in I al) case, rejected cbngorou. experiment, hat I Im-e n,any ca.es devi.e,J simple, n, safe, and oifioiem w.vs to .^iidy expIo.,ve and noxio.s .obsta.ce.. Sec, for e.aniple. Hydrogen, pp. 29, 30, and Chlorine, ' pp. 138 1S9 The wood-ents whioh represent CONTENTS. the experiment, are, with a single exception. Fig. 23, made fi-onr the photographs or .l™g. oi the apparatus in actual use. For the .elected eut. wh.ch :„ustrate the OBSBEVATION AND EXPERIMENT. description, of hi.ioncal or indn^t^i rAOR am work, unable to give the credit r experiment; way OhBcrvation 9 Ch«niistrj' which to stii
XI CONTENTS. CONTENTS. 2 FACr. carbon CHEMISTRY OP THE ATMOSPHERE. rrepju-alion of; properties of; «.. .lio-vUle: . hydrogen and carbon -..ou,i of *^^;rx'r oxygen removed ; by sul- Liwoisier'a IVoiii iur t.'xj)eii]us;[it ; ^^^ phur and 65 £)hos{)lionis \'\ nietliano ATOMS. ELEMENTS, MOLECDLES, AND Am: Nitrog'eii: properties imalysis I'lviwratioii of; ol'; composiiioiL of; a mixture; 66 of gases of; names symbols, tliliiit^ioii - . table of of the klements; The number a. '" focts of matter; RcHpiratioii Of unimals aTomic weights; thro, fonns produces in cliaiiges air , : md ; Mole^ ch.tu.gvnshed. of 77 vontilalioii bo carefully pliiiits to ; theories, „d ! gases, the about the ex pans, on ot — llm cuLES- some fael.'^ 'Exercises of siilpliuvio on Invest isjiitious action m : molecules; changes are Seorv'; chemical changes ... on 82 oxaliu acid anil action air pliosplioriis Llie ol' explamed; atom.c "nniltiple proportions'' ^oul molecular fonnula.s; atomic weights theory; symbols; ; COMPOUNDS OP NITROGEN, HYDROOEN, AND OXYGEN. ^^^ weights; reactions Oliicc of nitrogen in the uomjioiuids chiiriictcr of the iiir; AND SALTS. ACIDS. EASES. M of nitrogen and hases;^^ reaction of acid, Acids; salts; hydroxides; ammonia; the nascent state; i'roihiction of Aiiiiuoiiiii : neutral compounds amnionic in gas-works; jiroparalioii of ammonia; prop- 135 acids; of salts; of bases. erties of ammonia . - Chemical names: or its action on the acids composition ; ; by volunic 84 CHLORINE AND THE CHLORIDES. made from Witric At'id: OccuiTeiuic in iiiitim]; of, of propertip^ preparation and chlorine; - of Discovery Kodiuni nitrate; proporlicK ilccompoi-ition of; tlio by iii'; js bleaching; the r,n.OH,.Ks; ^'^ """IZL; 90 nitr:Ucs chlo, ides ae.d chlorides by bydrochlonc chlorine water ; ; metal; ..yi.rogek Nitrog'on Oxides: .Stne: ?.eparation of; composition ; "" compounds the oxide nitrogen products; the nitrous several five of volume; composition of J''^« ; 138 and the chloride. combining law of multiple oxides proportions the test for ehlori,.e " . law deduced ume ; ; ; weiKlLts il-2 fluorine Bromine; iodine The Chlorine Gro«p : ; relation of atomic weight., Exercises : Investigation of tests I'S their hydrogen e
; ; ; Xlll CONTENTS. xu CONTENTS. THE METALS. j of the metals number and abundance PAGE a metal ? What is The Sulphur Group: tellurium; hydrogen 192 Soleiiiuni ; occurrence in nature hohaviur guneral relation of atomie coiiii)Ound'i ; ; wei^lits to projierties li;] THE POTASSIUM GROUP. Sulphurous Oxide and Acid: Preparation of siilpliur- water; Deseription of; chemical action on Potassium: ous oxiilc; properties ot sulpliiiroiis oxick; sulphurous carbonate; potassnmi occurrence in nature; potassium acid Lleacliing Ili3 preparation of some ; hydroxide; experiments hi the and _^^ Sulpliuric Acid Sulphates; tlie Properties of liame test other salts ; upcs of the manufac- the te^t for the acid; iieiil; aeiil; nature; sodium Description of; occurrence in Sodium: ture of the acid; the sulphatejs svilphatcs by action : hydroxide; Hame test; study of carbonate; sodium of the iwid on metals; hy aetioii of the aeid on bases; sodium eoniponnds two sulphates of the same metal; other sulpbur acids reaction of 1(56 . of coniparison about ammonia; Facts Aiuniouium: Exercises Investigation of tests 173 : salts; the sul- formulas; the hypothetical metal; its JOl ammonium compounds phides; study of reactions of - PHOSPHORUS. AND THE NITROGEN GROUP. of membei-s; compari- The Potassium Group: Names phosphorus Discovery red properties of ])hos]>lioriis ^^ ; ; son of properties matches; phosphorus oxides and acids; phosphates; tlie manufacture of phosphorus 175 THE CALCIUM GROUP. Arsenicj: Arsenous oxide; arsenic oxide; arsenic and effect of iU occurrence in nature; hydroKon Jhirsh's test Calcium: The metal; J78 ; carbonate carbonate effect of acids on the heat on the The Nitrogen tlroup: ; 5Ieml>ers; their hydrogen com- carbonate; the sulphate; to pre- effect of water on the relation of atomic weights to properties pounds 182 compounds; to prepare the soluble . . ; pare the insoluble ^^ compounds AND THE CAEBON GROUP. SlIilCON, members; com- The Calcium Group: Xames of t],c Silicon: Its oxide; the cakbon ghoup; members; their study of properties; parison of atomic weights and hydrogen compounds; tlieir oxygen compounds; tlie reactions; flame colors characteristic 183 silicates Boron: The element; borax; boric acid; no hydrogen METALS OF THE ZINC GROUP. compound 185 compounds; study of reive- metal; Magnesium: The its magnesium compounds VALENCE. tions of uses of; compoiinds A Zinc: The metal; manufacture of; valence defined substitution atnnis difference in ; ; of in^luble compounds, and study by valence; the valence of; preparation of valence go\'crned of horoii; ^ the nuic group characteristic reactions valenee of an element useful in study of reactions; ; changes 188 n
XV CONTENTS. COI^TENTS. XIV PAOE ore; extraction from its ^ Occurrence in nature; .v THE IRON GROUP. compounds of n.ercury; the PAQE Of the n.etal; "^''Ses mercurous compounds; mercur.c com- Mangaiifisc Tlie metal oxides the potassium maii- its : ; fj^rides; ; ganate aniJ Ktndy of reactions with jjerniaiigiiimte reactions ; pounds; study of manganese salts; cobalt; uickrl 217 sul- from its in nature; extraction Oliver- Occnrrence metal, Iron: Occurrence of and reducing from galena; properties of the ores; roasting iron its ; Se- extraction 254 of the salt, of .Iver manofac- the three forms of iron the Ores east-iron reactions ; ; ; . S^und. of silver . ; Bessemer manufaeture of ture of wrought-iron; steel, compounds of process; cementation; iron tivo classes; GOLD AND PLATINUM. ; the two two chlorides; reactions for the distinctive ''washing"; in nature; obtained hy Gold: Occurrence classes; general reactions of iron salts 220 -V .2-9 "amalgamation"; properties of gold . obtained by Clironiiuin; The metal; its ore; the potassium chromate; the of properties nature; .... in Platinum: Occurrence the dichromate reactions of chromium salts 229 ' ^^^^^ ; metal; the platinum group The Iron Oroup comparison of properties 231 : OLASSIPICATION. ALUMINUM. of the non- they are made; the classes How alum; aluminum oxide; study of reactions Classes: Tlie metal; always classed not metals founded on valence; metals aluminum 233 of salts one way to group the metals; tills way; more than in -'"^ THE ANTIMONY GROOP. ways to classify the metals four principal by atomic weights; Antimony: 'I'lie metal; alloys of; bismuth; the anti- Cl.wsilication The If atm-al System; extension; the spiral mony group the I'cactions of ai'sonie, antimony, and Newland's discovery MendelejeUs ; ; JM ^^^ bismuth compared 235 vaciint places elements; the of on ClassHi cation founded s,>la- AND LEAD. V The Analytical System TIN : the preceding ex- analytical table drawn from Tin l^ilities Occurrence in nature from the ore extraction ; out what metal a : ; this com^e; how to find periments in compoimds of tin properties of the metal distinctive notes to identify the acid ; ; making contains; compound ; compounds general reaction for tms :ind reactions of iu bint for further work; form ; name the salt; to part; the salts of tin 239 268 of notes Ijcad: Occiirrencii in nature; extraction from the ore; two methods; lead oxides; lead carbonate; reactions of the salts of lead 242 THE COPPER GKODP. M. Copppp; Occurrence nature; extraction from ils'TJres; iji copper compounds; the sul- properties of the metal; ... study of reactions of the salts of copper phate 347 ;
ELEMFiXTARY CHHMISTRY. AND EXPEEIMENT. OISSEKVATION In the stiuly of Chemistry we are to learn some things There are two ways :ibout tlie ditfereut kinds of matter. have been found out, and in these in wliicli tliese things same ways we iran most easily lear:i wliat these things are. Tliese two ways of studying nature are ealled ohservution and eypi'vlmpnt. "WIk'u I look a.t something which is Observation. going on, and watch carefully to sec wliat happens, mj act To hiok at an olijei't so elojiely that we id an observation. can see its shape, its color, and wliatever else is visible about it, is an act of observation. know for example, I desire to as nuich as possible If, about a butterfly, the best way to learn to catch the it is down and remember butterfly, look at intently, note it would show mc that it has four The what butterfiy see. 1 wings, six legs, two long haii'-like bodies (antenuEe) reach- upon their ends, two ing forward from its head with knobs and prominent eyes which do not close nor large, dark, colors of its wings are due to and that the beautiful turn, rubbed off by my fingers. All a fine dust which is easily by holding the insect in the hand could these facts learir I and looking at it thoughtfully. way Knowledge which learned by obser- get in this I is vation.
: 10 OBSEEVAriON AND EXPERIMENT. U OBSERVATION AND EXPERIMENT. -But Experiment. instead of only looking at an if, danger I move slowly in the flaine to to avoid this it and object 1 find do soiiietluug to iia I how it, to see it will When it the liquid begins to boil heat all sides evenly. I lift behave or appeal' in ditferent conditions, this operation the tube into the hot air above the flame, where I can keep is an experiment. I watch to see it hot without boiling it too vigorously. Will 5 ciibifi centimeters of water dissolve as much as 10 "Whether the sugar remains, or becomes less and less. grains of granulated sugar ? I cannot iind out by simply Whether finally disappears. it all looking at and water. In order to leai'n what the siigai' almost or If the liquid at length becomes, as will, it faet IS, I may put the two things together in the right know we of hot water can that 5 quite transparent, shall ec. way, and if I do so I make an experiment. Thus: then stand the tube in the of sugar. I will dissolve 10 g. —I take a tall glass cylinder, J'-x. 2. and when cold I will look again and sec tube-rack, which Pig. it is a, 1, is gi-aduated to measure cubic centimeters, Whether 5 water can hold the 10 g. in solution. of and pour cc, '/nld water in syrup for use in another experiment. Let us keep this some some plants The sap trees and the juices of are of natural solutions of sugar in water, hut the quantity of sugar in 5 cc. of these Nothing but an juices is very small. experiment could have first shown that 5 cc. of water can dissolve so much we have found sugar as to do. it Ke. 1. experiments we often put But in up to the 5 00, mark." I transfer this water to one of together in ways in which na^ things the thin rouiiddwttoined cylinders, b, called a Fie. 2. test-tube For example, I wish ture never does. I also weigh out 10 g. of grmiulated sugar = and put it to know how sugar will behave in strong sulphuric acid. into the water in the tube i.« I now warm tlie tube in the Kature never puts these two things together, and the only flame of a Bunsen lamp, c. There is danger of breaking way I con find out how they will act in the presence of the tube if I heat it too suddenly, or too long in one spot, Thus them together. each other to bring is —I must If set along witlinut a graduated cylhuier uiie ' measure out 6 cc. of strong sulphuric acid Ex. maw he 2. very nearly by filling liis test-tulie one obtitii, cc. 5 above tlie ^vitli the cylinder a. Fig. 1, pour it into an empty test-tube, incii rounded bottom. The tube is supposed to be §- i.ich in diameter then rinse the cylinder and stand it on a small plate. Fig. 2. = If one must got along witbout a balance, he caii obtain about I now [lour the sugar syrup miule in the other experiment 10 g. of dry sugar by filling a teaspoon twite, = Pold a narrow strip of 1 am ready now to biing the two to- paper into tl.e shape of a trough and into this cylindei*. lav this in the inbe, wliioli should be field in a slantins position. The dry I pour the acid in a slender stream into the syrup, gether, sugar will slide safdy down this trough instead of clinging to the wet and watcli for evevy change that happens. I notice walls of the tube. A change in color.
OBSERVATION ANh KXPERIMENT. 12 A change volume CHKMICAT. ClIANGTCS. in (size). A chauge in temperature («"armer or colder). A new auliMtaiu'e unlike wugai' or Myrnp ur acid. my As soon experiment over I write, in note- tlio is i\A book, a sliort account of and the results just as ivliat I did, saw tliem. 1 The bulky mass of carbon that a faet eo;il-l)laek, liot is two substances or cliarooal is the resnit of bringing tliesc ' together. How do they differ How ! these changes. .iwlth The science of Chemistry is founded on facts which have been discovered by experiment, and the most natural ii'ay them? to .study Cliemistry is by tlie same means. The best «ay foi' scribe or nbbon of magnesium w.re s -^l take a piece the student is to make the experiments iiimself. The sec- ,,., ond best way them Jiiade by a teacher. In either tu see is remember that the object of mak- case the student should discover triitli. An ex|ierimeiit may ing experiments to is pretty and interesting, but value does not lie in its its ije solid. .Int. renndus but . .run.bbng Xo good for anything in the study exjieriment beauty. is finally Nothing — of Chemistry unless helps to reveal .'iome truth. it "'»w in i Jix. 4- The student should remember, not what he that it is al.'io, the same way hold a reads about experiments, or hears a teacdier say about them, iron wive iu piece c^f going to give him the best and quickest insight into that is the flame of the Bmi- Chemistry, but that whii'h he sees with his own eyes and sen lam]i, and see that own words. describes in his but hot, The metal becomes red To study Chemistry by experiment the student should — does not burn. obey the following rules; cold, is the when And finally, Arrange the ajiparatus and use it PMKthj as directed. 1. same substance as at first. 2, Watch (^arei'nllj- tu see every change which takes place, by Hoth metals were changed Note accurately on paper every important eliange;. very different ^:5j: li. but in heat, the 4. Compare these results with the facts stated in the The iron became hot m- rij. 3. ways. book, and correct those which are found to be wrong. may Stirdy carefully to see ho\\' certain inferences be 5. neia a^^ m the split and inserted The wire cau be atk'k. made from the results. i
17 CHEMICAL CHANGES. CHEMICAL CHANGES. 16 which brightens the burning of a colorless gas splinter. The shining droplets wliioh coat the cold walls of the tube are m^i-'mrij, and the gas in which a splinter bums with unusual brightness oxt/gun. is This a fine example of {'hymical change. But the most is water? chlorate it is hrst important thing to notice that in this change one sub- heating potassium is, The F«rs.-Ky L two substanj^j iinlik stance broken into two which are entirely unlike itself is afterwLd broken into Jted ^ - the ^ and unlike each Such a cheuiical change One is the white « other. called Is ,tself and each other. Ihe chloiate decomposition. ox.jgen. other is iguition-tubc, and the — Decomposition of Potassium Chlorate. At. 6. Po- experiments tassium chlorate a white solid. appeared in both these Before I heat it the is 'T^r'which lias coarse grains or crystals should be reduced to powder: I grind it in a mortar (Fig. f>). I jmt two grams of the powder into the ignition- tube,i Fig. 4. This quantity will fill about one inch of the tube. 1 put three heated in oxygen? ^4^^^^ or four cubic centimeters of blue litmus little a small wire around a _I wind the cud of .> solution into one test-tube, b, and as much r Fls. 6. lime-water into a second tube, Fig. 5. e, into the ox; gen and then lower it and provide a good cork end of the of for paeh. I put the iire, Notice over lime-water. rubber tube into the litmus, and then heat the chlorate just Fis 5, produced on the spark. What is effect as I did the red oxide before. Watch for and describe charcoal wastes away. Whether the The changes in the chlorate. niatch-fi.ne afterwards ? Win the oxygen brighten a The bubbles from the pipe in and my the litmus. iingei the tube with mouth of 1 now cover the After a while 1 put a match-flame into the mouth of it briskly. shake the tube and see that it burns with unusual brightness. This shows that the tube is filled with oxygen. I then put the end of the rubber tube over into the iime- water in e, and close b with its cork, in order to keep its oxygen for use further on. At length the boiling chlui'ate thickens, and soon after must be T]ie tube ' piece of diy cloth, or a sponge uleaii aiid dry. j\ ou die end of tied wire or stick, convenient for wiping tubes. is !i
CHEMItiTRY OF WATER. G4 3. If'ind the boilmg-point of alcohol. Fig. SO. 4. Find the hoWmg-point of a mixture of alcohol mid watfir ATMOSPHEKT:. CHEMISTHY OV THE made in the proportion of one volume of alcohol to to be an ago the aiv was thought two volumes of water. ivr-d veai-s 1 Use the appaiiitus shown in Fig. 30. Xote the temperature when the boiling begins, Tvu'u tlie lamp low and let the Iwiling go on slowly °'LlvoiiS''Spe.lme„t.-Tl,,.arP=.,*,»rf>irf.l»...e
67 CHEMISTRY OF THE ATMOSPHERE. CBByflSTltY OF THE ATMOSPHERE. 66 quickly, and some other things will burn more plrur a,nd the quantity of air in the receiver dimin- inci'eased. wliUt; sulphur, and afterwanl may be used instead. Let us try For some time longer heat was kept up, but no islied. tlie phosphorus. work further eliaiige took place, and part of «ai5 tlie tliis cork a slice half an inch thick Irom a ^5._I had (.ut sliown done. apparatus than at lie less aiv in tlic jj^.. fiist, than the much smaller by the iuereory rising in the jar, but instead of the air which is shape the my 1 bottle. wliieh was lost lie liad tlie new red substance in tlie flask. mouth of cup top of the cork into a shallow To iind out, Lavoisier "What wa? this red sulistance '/ erayou-powdei-, and rub it well with heated it in a tube so tixed that any gas whieli shoidd be moistened or better with a paste of produced would be caught in a vessel over mercury. The I put sulphur in plaster of Paris. red substanee beciuno black, then began to waste away the shal- this cup, place the cuji on while bubbles of a colorless gas were cauglit in the vessel ri?, 31. the water-pan, set fire water in prepared fiu' tlie piu'pose, aiid globules of shining mercury low bottom up.vard over as it, bottle and put a to the sulphur, gatliered on the walls of the tube above the heated part. Describe in Fig. 34. shown "What was tlie colorless gas? Lavoisier plunged a caudle- the candle burned with a dazzling light. flame into it The flame of the sulphur. ; is over. The action of the water when the burning The was oxj/ijen. gas after long time standing. whence came this oxygen to cojiibine with the mer- liut The change in the gas heated with cury wlien air in Lavoisier's flask "* ph'isphorns, not larger tlian a T}k' it iva.s '.' ^ U—'^ £;. ^i^f' l"'^''" must have given it to the mercury, and so the experi- holding air wheat, with aiiutln^r bottle ROod-si«Hl kernel of ment proved that oxygen is one constituent ol' air. did the sulphur, and I just treat iis it 1 "Hi) cc. about In till! flask and the glass jar (Fig. 33) there was still left action of the water afterward, a-ain describe the flame, the a large quantity of air-like substance. But on ])lungiiig a after standing some the appearance of the gas inside and candle-flaiiie into it the flame was put out as it would hav
CHEMISTRY OF THE ATMOSPHERE. 68 CHEMISTRY OF THE ATMOSPHERE. 69 — at once jguitu a match, iniuover the bottle, aiul I Properties of Nitrogen, Nitrogen is a colorless gas insert the flajne; thii i.itrogeii will (pieiich than air (Ex. 46), but a liter of It is lighter I leave the bottle (Exa. 44). 4;i, it. uncovered. 1 tiuat the bottle used in Ex. 44 in the same weighs fourteen times as much iis a liter of hydrogen. it way the nitrogen again puts out the flame. 1 leave quench fire (Ex. 45), because it cannot iinite with It will this ; bottle, also, uncovered. tlie elements of the fuel as oxygen does, in fact, nitro- — I now again insert a match-flame in the bottle will jiot only the elements. gen is tlie least at^tive of It Jix. 46. quench breathed insteail of quench fire, bnt air it will uncovered, and afterwai'd in the other. first left if The flame cannot be poisonous, since we inhale it Yet not quenehed. life also. it ifi with every breath without injury. It is the oxygen of the Wliat does this prove? — air that sustains life, and it is the absence of oxygen, and EX.47. I now aiid a little blue litmus-water to the when pure not the jiresence o£ nitrogen, which carrses death water in the bottle in which sulphur was burned. nitrogen breathed. is — The Mote the change of oolor. Compare Ex. 8. Other Constituents of Air. contains also air What causes this change of color '; proved by placing This water in form of invisible vapor. is — JSX.4S. a 'piece of caustic potash in an open dish. The potash aild blue I litmus- water to the water in the second bottle which w-as uncovered in will very soon become wet, and if left for some time it left Ex. 45; it changes from blue to red. will be dissolved by the water which it takes from the air. Can you explahi this change of color? Try it. The moisture to be seen on the outside of a vessel — Burning of Sulphur. aummer the eoiulensed water-va|>or of the of ice-water in Sulj^hur, when burning with is its T)ew and hoar-frost are also the water of the blue combines with oxygen, and the two flame, feeiilc air, air. become sulphiu- dioxide. The water soon dissolves the changed by cold from vapor liquid and solid forms. t
CHEMISTRY OF THE ATMOSPHERE. CHEMISTRY OF THE ATMOSPHFAiE. 71 70 To do we below the covk and open the piiich-eock p a moment, to and then imprison a vesselfiil of will this air, let the liquid run down and fill the tubes completely. which oxygen and will abaoi-b both into aliijuid it I'vui tlift I We carefully take off the drop, which hangs the carbon dioxide completely, and leave the nitrof^en. pan then measure the niti'ogeu which is left, and we can at the lower end of the tidie below the find out how much there was oi the other two, by measur- a piece of cork, with filter-paper. 8 ^M'^ft ing the liquid which has gone into the tube to take their np over the cork \i press the tube f air-tiglitjas seen in until the joint is place. — OuK —I Apparatus. minute put the Ex. and after a take a test-tube, J (Fig, Fig. 37, 49. t A the open hole of six-inch tube, ^ inch in 35) to hold the eork. rod s into tlu? air. have now imprisoned a tubeful of air an eight-inch tube of the same diameter, will do I ; ; none can get out, and no more can The rubber diameter stopper, so better. is c, is large that its small end will enter the tube only get in. I left the hole in the cork open, be- two about a half-inch. lioles to close It lias ; were not open the pressure one I have a solid rod of glass, s ; for the other, cause if it the cork would crowd the air below, a glass tube reaching j'ust a very little below the oi' ^'^- ^' A piece of thin rubber tubing, and there would be too much in the cork, as shown. tube; and then, too, handling the tube warmed it, and the There is a pinch- k, is cut about six inches long. may volume of air changes with heat. by which be pinched so aa walls cock, p, its F is With Fig. aa. the hole open, the air in the a small glass funnel. completely. to close it tube soon comes to be just as warm The lower end of h I stretch over arid just as mucli pressed as the air and upper the tube in the cork its c, Whenever a gas of any kind outside. end over the stem of F, and then I fix measured its tcmiierature and to he I place the funiiel in the clam]i of the is pressure must be the savie as those of shown and in Fig. support, as re- ',Hj, the air oiitaidc. move the rod s. Liquid. — To — now The a b.sobption. absorb the oxy- TuF. press I stream of gen and carbon dioxide gases I use the pinch-cock }>; a little a mixture of pyrogallie acid and po- the liquid falls into t at once, and then drops follow, or, if the tube be tassium hydrate. FiB 36. slightly inedined, a slender stream will I take a small teaspoonfnl of the down and pour on It will continue 10 acid of flow side. solid ec. its it To any oxy- to enter as long as there is water will soon dissolve. this FiB 35. it ; gen or carbon dioxide for it to absorb, and then stop. T then avid 5 cc. of strong solution of potassium hydrate, ft once pour hold the dish Mid into the funnel. The gas which is left in the tube is nitrogen. Ivext, i it E