A System of Instruction in the Practical Use of the Blowpipe / Being A Graduated Course Of Analysis For The Use Of Students And All Those Engaged In The Examination Of Metallic Combinations

by Anonymous

2. Reducing flame.

Color of Bead.
	Substances which produce this color
	in the hot bead.		in the cold bead.
Colorless
	Silica (only slightly soluble)		Silica (only slightly soluble).
	Alumina		Alumina.
	Oxide of Tin		Oxide of Tin.
	Baryta		Baryta	With an intermittent flame opaque-white.
	Strontia		Strontia
	Lime		Lime
	Magnesia		Magnesia
	Glucina		Glucina
	Yttria		Yttria
	Zirconia		Zirconia
	Thoria		Thoria only when saturated
	Oxide of Lanthanum		Oxide of Lanthanum
	Oxide of Cerium		Oxide of Cerium.
	Oxide of Didymium		Oxide of Didymium.
	Oxide of Manganese		Oxide of Manganese.
	Tantalic Acid		Tantalic Acid.
	Oxide of Silver	After long continued blowing. Otherwise grey.	Oxide of Silver
	Oxide of Zinc		Oxide of Zinc	After long continued blowing. Otherwise grey.
	Oxide of Cadmium		Oxide of Cadmium
	Oxide of Lead		Oxide of Lead
	Oxide of Bismuth		Oxide of Bismuth
	Oxide of Antimony		Oxide of Antimony
	Oxide of Nickel		Oxide of Nickel
	Telluric Acid		Telluric Acid
Yellow, red, and brown.
	Oxide of Iron,	red	Oxide of Iron.
	Titanic Acid,	yellow
	Pelopic Acid,	brown	Pelopic Acid.
	Ferruginous Titanic Acid,	blood red	Ferruginous Titanic Acid.
	Ferruginous Niobic Acid,	blood red	Ferruginous Niobic Acid.
	Ferruginous Pelopic Acid,	blood red	Ferruginous Pelopic Acid.
	Ferruginous Tungstic Acid,	blood red	Ferruginous Tungstic Acid.
	Vanadic Acid	brownish
	Oxide of Chromium,	reddish
Violet or Amethyst.
	Niobic Acid	in large proportion	Niobic Acid	in large proportion.
			Titanic Acid.
Blue.
	Oxide of Cobalt		Oxide of Cobalt.
	Tungstic Acid		Tungstic Acid.
	Niobic Acid	in very large proportion.	Niobic Acid	in very large proportion.
Green.
	Oxide of Uranium		Oxide of Uranium.
	Molybdic Acid		Molybdic Acid.
			Vanadic Acid
			Oxide of Chromium.
Opaque-grey. (The opacity generally becomes distinct during cooling.)
	Oxide of Silver		Oxide of Silver.
	Oxide of Zinc		Oxide of Zinc.
	Oxide of Cadmium		Oxide of Cadmium.
	Oxide of Lead		Oxide of Lead.
	Oxide of Bismuth		Oxide of Bismuth.
	Oxide of Antimony		Oxide of Antimony.
	Oxide of Nickel		Oxide of Nickel.
	Telluric Acid		Telluric Acid.
Opaque-red and reddish brown.
	Oxide of Copper		Oxide of Copper.

TABLE II.

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Metallic Oxide.	Behavior with Borax on Platinum wire	Behavior with Mic. Salt on Platinum wire
1. Oxide of Cerium, C2O3.
in the oxidizing flame.	Dissolves into a red or dark yellow glass (similar to thatproduced by iron). During cooling, the color diminishes in theintensity and becomes finally yellow. If much oxide be dissolved,an opaque bead may be obtained with an intermittent flame, and astill larger quantity renders it opaque spontaneously.	The color of the bead becomes paler, so that a bead, which isyellow in the oxidizing flame, is rendered colorless. With alarge quantity of oxide the bead becomes white and crystallineon cooling.
in the reducing flame.	As with borax. During the process of cooling the color entirelydisappears.	Both, when hot and cold, the bead is colorless, by whichcharacter oxide of cerium may be distinguished from oxide ofiron. The glass remains clear even when containing a largequantity of the oxide.
2. Oxide of Lanthanum, LaO.
in the oxidizing flame.	Dissolves into a colorless glass, which, when sufficient oxideis present, may be rendered opaque with an intermittent flame,and becomes so spontaneously on cooling, when a still largeramount is dissolved.	As with borax.
in the reducing flame.	As in the oxidizing flame.	No reaction.
3. Oxide of Didymium, DO.
in the oxidizing flame.	Dissolves to a clear dark amethystine glass.	As with borax.
in the reducing flame.	No reaction.	No reaction.
4. Oxide of Manganese, Mn2O3.
in the oxidizing flame.	Affords an intense amethyst color, which on cooling becomesviolet. A large quantity of the oxide produces an apparentlyblack bead, which however, if pressed flat, is seen to betransparent.	With a considerable quantity of oxide an amethyst color isobtained, but never so dark as in borax. With but little oxide acolorless bead is obtained, in which, however, theamethyst-color may be brought out by adding a little nitre.While the bead is kept fused, it froths and gives off bubbles ofgas.
in the reducing flame.	The colored bead becomes colorless. With a large amount of theoxide, this reaction is best obtained upon charcoal, and isfacilitated by the addition of tin foil.	The colored bead immediately loses its color, either on platinumwire or on charcoal. After the reduction the fluid bead remainsstill.
5. Oxide of Iron, Fe2O3.
in the oxidizing flame.	With a small proportion of oxide, the glass is of a yellowcolor, while warm, and colorless when cold; with a largerproportion, red, while warm, and yellow, when cold; and with astill larger amount, dark-red, while warm, and dark-yellow, whencold.	With a certain amount of oxide, the glass is of a yellowish-redcolor, which on cooling changes to yellow, then green, andfinally becomes colorless. With a large addition of oxide, thecolor is, when warm, dark red, and passes, while cooling, intobrownish-red, dark green, and finally brownish-red. During thecooling process, the colors change more rapidly than with borax.
in the reducing flame.	Treated alone on platinum wire, the glass becomes of abottle-green color (F3O4), and if touched with tin, itbecomes of a pale sea-green. On charcoal with tin, it assumes atfirst a bottle-green color, which by continued blowing changesto a sea-green (FeO).	With a small proportion of oxide there is no reaction. With alarger amount the bead is red, while warm, and becomes oncooling successively yellow, green, and russet. With theaddition of tin the glass becomes, during cooling, first greenand then colorless.
6. Oxide of Cobalt, CoO.
in the oxidizing flame.	Colors the glass of an intense smalt blue both whilst hot andwhen cold. When much oxide is present, the color is so deep asto appear black.	As with borax, but less intensively colored. During cooling thecolor becomes somewhat paler.
in the reducing flame.	As in the oxidizing flame.	As in the oxidizing flames.
7. Oxide of Nickel, NiO.
in the oxidizing flame.	Colors intensely. A small amount of oxide affords a glass which,while warm, is violet, and becomes of a pale reddish-brown oncooling. A larger addition produces a dark violet color in thewarm and reddish-brown in the cold bead.	Dissolves into a reddish glass which becomes yellow on cooling.With a large addition of the oxide, the glass is brownish whilehot, and orange when cold.
in the reducing flame.	The oxide is reduced and the metallic particles give the bead aturbid grey appearance. If the blast be continued the metallicparticles fall together without fusing, and the glass becomescolorless. This reaction is readily obtained with tin uponcharcoal, and the reduced nickel fuses to a bead with the tin.	On platinum wire the nickeliferous bead undergoes no change.Treated with tin upon charcoal, it becomes at first opaque andgrey, and after long continued blowing the reduced nickel formsa bead, and the glass remains colorless.
8. Oxide of Zinc, ZnO.
in the oxidizing flame.	Dissolves easily into a clear colorless glass, which, when muchoxide is present, may be rendered opaque and flocculent by anintermittent flame, and becomes so spontaneously with a stilllarger addition. When a considerable quantity is dissolved, aglass is obtained which is pale yellow, while hot, and colorlesswhen cold.	As with borax.
in the reducing flame.	On platinum wire the saturated glass becomes at first opaque andgrey, but by a sustained blast is again rendered clear. Oncharcoal the oxide is gradually reduced; the metal isvolatilized and in crusts the charcoal with oxide.	As with borax.
9. Oxide of Cadmium, CdO.
in the oxidizing flame.	When in very large proportion, dissolves to a clear yellowglass, which becomes nearly colorless on cooling. When the oxideis present in any considerable quantity, the glass can berendered opaque with an intermittent flame, and, with a largeraddition, it becomes so spontaneously on cooling.	When in very large proportion dissolves to a clear glass, havinga yellow tinge, while hot, which disappears on cooling, and whenperfectly saturated, becomes milk-white.
in the reducing flame.	Upon charcoal ebullition takes place and the oxide is reduced.The metallic cadmium is volatilized and incrusts the charcoalwith its characteristic deep yellow oxide.	On charcoal the oxide is slowly and imperfectly reduced. Thereduced metal forms the characteristic incrustation on thecharcoal, but the is thin and does not exhibit its color clearlyuntil quite cold. The addition of tin hastens the reaction.
10. Oxide of Lead, PbO.
in the oxidizing flame.	Dissolves readily to a clear yellow glass, which loses its colorupon cooling, and when containing much oxide can be rendereddull under an intermittent flame. With a still larger additionof oxide it becomes opaline yellow on cooling.	As with borax, but a larger addition of oxide, required toproduce a yellow color in the warm bead.
in the reducing flame.	The plumbiferous glass spreads out on charcoal, becomes turbid,bubbles up, until the whole of the oxide is reduced, when itagain becomes clear. It is, however, difficult to bring the leadtogether into a bead.	On charcoal the plumbiferous glass becomes grey and dull. Withan over dose of oxide a part is volatilized and forms anincrustation on the charcoal beyond the bead. The addition oftin does not render the glass opaque, but somewhat more dull andgrey than in its absence.
11. Oxide of Tin, SnO2.
in the oxidizing flame.	In small quantity dissolves slowly into a clear colorless glass,which, when cold, remains clear, and cannot be rendered opaquewith an intermittent flame. If a saturated bead, which has beenallowed to cool, be reheated to incipient redness, it loses itsrounded form and exhibits imperfect crystallization.	In small quantity dissolves very slowly to a colorless glass,which remains clear on cooling.
in the reducing flame.	A glass containing but little oxide undergoes no change. If muchof the latter be present, a part may be reduced upon charcoal.	The glass undergoes no change, either on charcoal or platinum wire.
12. Oxide of Bismuth, BiO3.
in the oxidizing flame.	Dissolves readily to a clear glass which with a small amount ofthe oxide is yellow, while warm, and becomes colorless oncooling. With a larger addition, the glass is, in the hot state,of a deep orange color, which changes to yellow and finallybecomes opaline in process of cooling.	Dissolves in small quantity to a clear colorless glass. A largeraddition affords a glass which, while warm, is yellow, andbecomes colorless on cooling. When in sufficient proportion theglass may be rendered opaque under an intermittent flame, and astill larger addition of oxide renders the bead spontaneouslyopaque on cooling.
in the reducing flame.	A glass becomes at first grey and turbid, then begins toeffervesce, which action continues during the reduction of theoxide, and it finally becomes perfectly clear. If tin be added,the glass becomes at first grey from the reduced bismuth, but,when the metal is collected into a bead, the glass is againclear and colorless.	On charcoal, and especially with the addition of tin, the glassremains colorless and clear, while warm, but becomes on coolingof a dark grey color and opaque.
13. Oxide of Uranium, U2O3.
in the oxidizing flame.	Behaves similarly to oxide of iron, with the exception that thecolor of the former is somewhat paler. When sufficientlysaturated, the glass may be rendered of an opaque yellow by anintermittent flame.	Dissolves to a clear yellow glass, which assumes ayellowish-green color on cooling.
in the reducing flame.	Affords the same color as the oxide of iron. The green glassobtained in this flame, if sufficiently saturated, can berendered black by an intermittent flame, but it has under thesecircumstances no enameline appearance. On charcoal, with theaddition of tin, the glass takes a dark green color.	The glass assumes a beautiful green color, which becomes morebrilliant as the bead cools. The addition of tin upon charcoalproduces no further change.
14. Oxide of Copper, CuO.
in the oxidizing flame.	Produces an intense coloration. If in small quantity, the glassis green, while warm, and becomes blue on cooling. If in largeproportion, the green color is so intense as to appear black.When cool, this becomes paler, and changes to a greenish blue.	With an equal proportion of oxide, this salt is not so stronglycolored as borax. A small amount imparts a green color in thewarm and a blue in the cold. With a very large addition ofoxide, the glass is opaque in the hot state, and after coolingof a greenish-blue.
in the reducing flame.	If not too saturated, the cupriferous glass soon becomes nearlycolorless, but immediately on solidifying assumes a red colorand becomes opaque. By long continued blowing on charcoal, thecopper in the bead is reduced and separates out as a smallmetallic bead, leaving the glass colorless. With the addition oftin, the glass becomes of an opaque dull-red on cooling.	A tolerably saturated glass assumes a dark green color under agood flame, and on cooling becomes of an opaque brick-red, themoment it solidifies. A glass containing but a small proportionof the oxide becomes equally red and opaque on cooling, iftreated with tin upon charcoal.
15. Oxide of Mercury, HgO.
in the oxidizing flame.	No reaction.	No reaction.
in the reducing flame.	No reaction.	No reaction.
16. Oxide of Silver, AgO.
in the oxidizing flame.	The oxide is partly dissolved and partly reduced. In smallquantity, it colors the glass yellow while warm, the colordisappearing on cooling. In larger quantity, the glass is yellowwhile warm, but during cooling becomes paler to a certain point,and then again deeper. If reheated slightly, the glass becomesopalescent.	Both the oxide and the metal afford a yellowish glass, which,when containing much oxide becomes opaline, exhibiting a yellowcolor by daylight and a red one by artificial light.
in the reducing flame.	On charcoal the argentiferous glass becomes at first grey fromthe reduced metal, but afterwards, when the silver is collectedinto a bead, it becomes clear and colorless.	As in borax.
17. Oxide of Platinum, PtO2. 18. Oxide of Palladium, PdO2. 19. Oxide of Rhodium, R2O3. 20. Oxide of Iridium, Ir2O3. 21. Oxide of Ruthenium, Ru2O9. 22. Oxide of Osmium OsO2.
in the oxidizing flame.	Are reduced without being dissolved. The reduced metal, beinginfusible, cannot however be collected into a bead.	As in borax.
in the reducing flame.	As in the oxidizing flame.	As in borax.
23. Oxide of Gold, Au2O3.
in the oxidizing flame.	Is reduced without being dissolved and can be collected into abead on charcoal.	As in borax.
in the reducing flame.	As in the oxidizing flame.	As in borax.
24. Titanic Acid, TiO2
in the oxidizing flame.	Dissolves readily to a clear glass which, when but little acidis present, is colorless, but when in larger proportion, yellow,and, on cooling, colorless. When sufficiently saturated, it maybe rendered opaque with an intermittent flame, and with a stilllarger addition of the acid becomes so spontaneously on cooling.	Dissolves readily to a clear glass, which, when sufficientlysaturated, is yellow white hot, and becomes colorless oncooling.
in the reducing flame.	In small proportion, it renders the glass yellow in largerquantity dark-yellow or brown. A saturated bead assumes ablue enamel-like appearance under an intermittent flame.	The glass obtained in the oxidizing glame becomes yellow in thehot state, but on cooling assumes a beautiful violet color. Iftoo saturated, this color is so deep as to appear opaque, but isnot enameline. If the titanic acid contains iron, the glassbecomes on cooling of a brownish-yellow or red color. Theaddition of tin neutralizes the iron, and the glass then becomesviolet.
25. Tantalic Acid, TaO3.
in the oxidizing flame.	Dissolves readily to a clear colorless glass, which, whensufficiently saturated, may be rendered opaque with anintermittent flame, and with a larger addition of the acidbecomes spontaneously enameline on cooling.	Dissolves readily to a clear glass, which, when it contains alarge proportion of the acid, is yellow while warm, but becomescolorless on cooling.
in the reducing flame.	As in the oxidizing flame.	The glass obtained in the oxidizing flame undergoes no change,nor does it, according to H. Rose, alter by the addition ofsulphate of iron.
26. Niobic Acid, Ni2O3
in the oxidizing flame.	Behaves in a similar manner to tantalic acid, but the glassrequires a very large dose of the acid to render it opaque underan intermittent flame. With an increased amount of the acid, theglass is clear and yellow, while warm, but becomes on coolingturbid, and when quite cold is white.	Dissolves in large quantities to a clear colorless glass.
in the reducing flame.	The glass obtained in the oxidizing flame and which has becomeopalescent on cooling, is rendered clear in the reducing flame.With a larger addition of the acid, it becomes dull, and of abluish-grey color on cooling, and a still larger amount ofrenders it opaque and bluish grey.	If the acid be not present in too large a proportion, the glassremains unchanged. An additional amount of the acid renders itviolet, and a still larger quantity affords a beautiful pureblue color, similar to that produced by tungstic acid. If tosuch a bead some sulphate of iron be added, the glass becomesblood-red. The addition of peroxide of iron renders the glassdeep yellow while warm, the color becomes paler on cooling.
27. Pelopic Acid, Pp2O3.
in the oxidizing flame.	Behaves similarly to the preceding.	Dissolves even in large quantity to a colorless glass.
in the reducing flame.	A bead containing sufficient of the acid to render itspontaneously opaque on cooling, has a greyish color.	With sufficient dose of the acid, the bead becomes brown with aviolet tinge. This reaction is readily obtained upon charcoal.Sulphate of iron renders the bead blood-red.
28. Oxide of Antimony, SbO3.
in the oxidizing flame.	Even when in large proportion, dissolves to a clear glass, whichis yellow when warm, but almost entirely loses its color oncooling. On charcoal, the antimonious acid may be almostexpelled, so that tin produces no further change.	Dissolves with ebullition to a glass of a pale yellow colorwhile warm.
in the reducing flame.	A bead, that has only been treated for a short time in theoxidizing flame, when submitted to the reducing flame becomesgrey and turbid from the reduced antimony. This soon volatizesand the glass again becomes clear. The addition of tin rendersthe glass ash-grey or black, according to the amount of oxide itcontains.	On charcoal, the saturated glass becomes at first dull, but assoon as the reduced antimony is volatilized, it again becomesclear. With tin, the glass is at first rendered grey by thereduced antimony, but by continued blowing is restored toclearness. Even when the glass contains but little oxide, tinproduces this reaction.
29. Tungstic Acid, WO3.
in the oxidizing flame.	Dissolves readily to a clear colorless glass. In largeproportion it renders the borax yellow, while warm, and with astill greater addition the bead may be made opaque with anintermittent flame. If more be then added, this reaction takesplace spontaneously.	Dissolves to a clear glass, which, when saturated, is yellow inthe hot state.
in the reducing flame.	When the oxide is present in small quantity, the glass undergoesno change. With a larger proportion, the glass is deep yellowwhile warm, and yellowish-brown when cold. This reaction takesplace upon charcoal, with a small quantity of the acid. Tinproduces a dark coloration, when the acid is not present in toogreat a quantity.	The glass is of a pure blue. If the tungstic acid contain iron,the glass becomes blood-red on cooling, similar to titanic acid.In this case, tin restores the blue color, or, if iron be inconsiderable quantity, renders it green.
30. Molydbic Acid, MO3.
in the oxidizing flame.	Dissolves readily and in large quantity. When but little isdissolved, the glass is yellow while hot and colorless whencold. When in larger quantity yellow while warm and opaline whencold, and a further addition of acid renders it yellow whenwarm, the color, on cooling, changing first to a pale enamelblue, and then to an enamel white.	Dissolves to a clear glass, which, when sufficient acid ispresent, is of a yellowish-green color when warm, and becomesnearly colorless on cooling. On charcoal, the glass becomesdark, and when cool has a beautiful green color.
in the reducing flame.	The glass, which has been treated in the oxidizing flame,becomes, when the acid is not present in too large a quantity,brown, and when in large quantity, perfectly opaque. In astrong flame, oxide of molybdenum is formed which is visible inthe yellow glass in the form of black flakes. If the glassappear opaque, it should be flattened with the forceps.	The glass becomes of a bottle-green color, which on cooling,changes to a brilliant green, similar to that produced by oxideof chromium. The reaction on charcoal is precisely similar. Tinrenders the color somewhat darker.
31. Vanadic Acid, VaO8.
in the oxidizing flame.	Dissolves to a clear glass, which is colorless when only a smallquantity of acid is present, and yellow when containing a largerproportion.	As with borax.
in the reducing flame.	The yellow color of the glass changes to a brown when warm and achrome-green on cooling.	As with borax.
32. Oxide of Chromium, Cr2O3.
in the oxidizing flame.	Affords an intense color, but dissolves slowly. A smallproportion colors the glass yellow when warm, and yellowishgreen when cold; a larger addition produces a dark red colorwhen warm, which, on cooling, becomes yellow and finally abrilliant green with a tinge of yellow.	Dissolves to a clear glass which has a pink tinge while warm,but on cooling becomes dusky green, and finally brilliantlygreen.
in the reducing flame.	A small quantity of the oxide renders the glass beautifullygreen both when warm and when cold. A larger addition changes itto a darker emerald green. Tin produces no change in the color.	As in the oxidizing flame, except that the colors are somewhatdarker. Tin produces no further change.
33. Arsenious Acid, AsO3.
in the oxidizing flame.	No reaction.	No reaction.
in the reducing flame.	No reaction.	No reaction.
34. Tellurous Acid, TeO2.
in the oxidizing flame.	Dissolves to a clear colorless glass which, when treated oncharcoal, becomes grey and dull from particles of reducedtellurium.	As with borax.
in the reducing flame.	As in the oxidizing flame.	As with borax.

7. EXAMINATIONS WITH CARBONATE OF SODA.

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The carbonate of soda is pulverized and then kneaded to a paste with water; the substance to be examined, in fine powder, is also mixed with it. A small portion of this paste is placed on the charcoal, and gradually heated until the moisture is expelled, when the heat is brought to the fusion of the bead, or as high as it can be raised. Several phenomena will take place, which must be closely observed. Notice whether the substance fuses with the bead, and if so, whether there is intumescence or not. Or, whether the substance undergoes reduction; or, whether neither of these reactions takes place, and, on the contrary, the soda sinks into the charcoal, leaving the substance intact upon its surface. If intumescence takes place, the presence of either tartaric acid, molybdic acid, silicic, or tungstic acid, is indicated. The silicic acid will fuse into a bead, which becomes clear when it is cold. Titanic acid will fuse into the bead, but may be easily distinguished from the silicic acid by the bead remaining opaque when cold.

Strontia and baryta will flow into the charcoal, but lime will not. The molybdic and tungstic acids combine with the soda, forming the respective salts. These salts are absorbed by the charcoal. If too great a quantity of soda is used, the bead will be quite likely to become opaque upon cooling, while, if too small a quantity of soda is used, a portion of the substance will remain undissolved. These can be equally avoided by either the addition of soda, or the substance experimented upon, as may be required.

As silica and titanic acid are the only two substances that produce a clear bead, the student, if he gets a clear bead, may almost conclude that he is experimenting with silica, titanic acid being a rare substance. When soda is heated with silica, a slight effervescence will be the first phenomenon noticed. This is the escape of the carbonic acid of the carbonate of soda, while the silicic acid takes its place, forming a glass with the soda. As titanic acid will not act in the same manner as silica, it can be easily distinguished by its bead not being perfectly pellucid. If the bead with which silica is fused should be tinted of a hyacinth or yellow color, this may be attributed to the presence of a small quantity of sulphur or a sulphate, and this sometimes happens from the fact of the flux containing sulphate of soda. The following metals, when exposed with carbonate of soda to the reducing flame, are wholly or partially reduced, viz. the oxides of all the noble metals, the oxides and acids of tungsten, molybdenum, arsenic, antimony, mercury, copper, tellurium, zinc, lead, bismuth, tin, cadmium, iron, nickel, and cobalt. Mercury and arsenic, as soon as they are reduced, are dissipated, while tellurium, bismuth, lead, antimony, cadmium, and zinc, are only partially volatilized, and, therefore, form sublimates on the charcoal. Those metals which are difficult of reduction should be fused with oxalate of potassa, instead of the carbonate of soda. The carbonic oxide formed from the combustion of the acid of this salt is very efficient in the reduction of these metals. Carbonate of soda is very efficient for the detection of minute quantities of manganese. The mixture of the carbonate of soda with a small addition of nitrate of potassa, and the mineral containing manganese, must be fused on platinum foil. The fused mass, when cooled, presents a fine blue color.