110 ABSTRAflTS OF CHEMICAL PAPERS. In o rg a n i c C he m i s t r y. Combustion of Nitrogen : a Lecture-experiment. By H. KXMMERER (Veut. Chenz. Ges. Ber., x, 1684).-The direct combustion of nitrogen may be demonstrated by plungingan ignited piece of mag- nesium ribbon, 30-40 C.C. long, into a two-litre flask full of air. After the experiment the presence of nitrogen tetroxide is recognisable by its odour, and by its peculiar colour after the magnesia has settled: or it may be rendered more apparent by shaking up in the flask a solution of potassium iodide acidulated with acetic acid, and adding starch-paste, whereupon the dark-blue colour of starch iodide is produced. J. R. Combustion of Zinc and Cadmium : Lecture-experiments. By FRIDER~CH GRAMP (Dewt. Chern. Ges. Ber., x, 1684).-Tlie com- bustion of zinc may be shown i n a striking manner by compressing zinc-turnings into a loose bundle some 40 mm.long and 20 mm, in diameter, and holding one end of the bundle, by means of tongs, in a gas-flame. The turnings take fire almost instantly and burn with a large dull-green flame, giving off dense white fumes of oxide whichINORGANIC CHEMISTRY. 111 speedily condenses in flocks about the room. Or a heap of zinc- turnings on an iron plate may be ignited by a gas-flame. After the combustion there remains on the plate a large quantity of zinc oxide of a deep yellow colour while hot. Cadmium, heated in a small porcelain crucible over the blowpipe, readily takes fire and burns with a dull-red flame, emitting dense brown clouds of oxide.J. R. Apparently Anomalous Decompositions effected by Carbonic Acid. By FR. M OHR (Liehiy’s Acmalen, clxxxv, 286--295).-The results detailed below were obtained by passing carbon dioxide, washed with sodium carbonate, into a flask containing solutions of the various substances experimented with, until no more of the gas was absorbed, all air having been first swept out of the flask. Burium acetate (10 grams in 100 C.C. of water), when saturated with carbon dioxide, deposited barium carbonate weighing 0.887 gyam = 0.678 gram of acetic acid displaced. Calcium and strontium acetates gave no precipitate with carbon dioxide. Zinc acetate (10 grams in 100 C.C. of water), when saturated with the gas, deposited a crystalline precipitate containing 0.018 gram of carbon dioxide.The filtered liquid became turbid when heated, owing to decomposition of zinc bicarbonate dissolved in it. Lead acetate (10 grams in 100 C.C. of water) speedily became turbid and deposited 4.715 grams of lead carbonate. The free acetic acid in the liquid was found by titration to amount to 1.976 grams, so that 73.6 per cent. of the lead acetate employed was decomposed in the experiment. I n the preceding cases the action of carbon dioxide may be accounted for by the fact that insoluble carbonates are formed. But there are cases in which similar decompositions are effected, although no pre- cipitate is formed. Neictral potassium chromate ( 5 grams in 100 C.C. of water) rapidly absorbed an amount of carbon dioxide which, when afterwards ex- pelled by boiling and absorbed by baryta-water, gave 2.765 grams of barium carbonate = 0.596 grams of carbon dioxide. Borua (5 grams in 100 C.C.of water) absorbed a large quantity of carbon dioxide, remaining clear. The solution, after boiling, contaiiied free boric acid and sodium carbonate. Sodium. phosphate (10 grams in 100 c c. of water) absorbed 0.627 gram of carbon dioxide, which was completely expelled by boiling. Microcosmic sa7t (10 grams in 100 c.c.) absorbed 0.631 gram of carbon dioxide. Sodium acetate (10 grams in 100 c.c.) absorbed 0.240 gram of carbon dioxide. Sodiufm a i ~ d yotnssiurn taytl-ate in aqueous solution absorbed carbon dioxide, and deposited acid potassium tartrate. J. R. Purification of Hydrogen. By E u G. V A R E N N E and E w. H E R R E (BdZ. Soc.Chirn. [el, xxviii, 52:3--.524).-The gas is passed through a solution of 2 parts of potassium bichromate in 20 parts of water and112 ABSTRACTS OF CHEMICAL PAPERS. 1 part of sulphuric acid, which acts as effectively as potassium per- manganate recommended by Schobig. The gas must be washed with potash to free it from traces of acids. L. T. 0's. Preparation of Iodic Acid. By W. S T E VE N s o N (Chem. News, xxxvi, EOl).-Dissolve 2 parts baryta in 4 parts boiling water, add gradually 3 parts iodine, and filter when the solution is neutral and colourless. The precipitated barium iodate may be decomposcd with sulphuric acid, and the liquid, after filtration, evaporated in a vacuum ; iodic acid is then obtained. The first filtrate containing barium iodide may be used for the preparation of hydriodic acid by decomposing with sulphuric acid.M. M. P. M. Change of Colour in certain Double Iodides. By R. BOTTGER (Clzen~. Centr., 1877, p. 2).-This change of colour, first observed by Meusel, is illustrated by the author in the following manner:-By coating the outside of a beaker made of tin-plate with mercuric iodide and argentic iodide (with the aid of " Cowdie pine resin " varnish) and of a second beaker with mercuric iodide and cuprous iodide, and filling them with water of about 70" to 80" ; the yellow colour of the former is converted into a deep orange, while the red colour of the latter is changed t o a blackish-brown shade. By emptying the beakers very quickly and refilling them with water of ordinary tem- perature, the original colours are reproduced.This interesting change of colour may in this manner be repeated several times. D. B. On some Thionates. By H. BAKE R (Chem. Nezus, xxxvi, 203) .- 1 part dissolves Sp. gr. at 15.5" = 4.536. Lead Dithiowute.-l part dissolves in 0.86'3 of water at 28.5". Sp. gr. Calcium Dithio?Late.--Sp. gr. at 11" = 2.176. Nickel Dithionate.-1 part dissolves in 0.897 of water at 12". Magizesiurn Dit1zionate.-Oblique prisms. Sodium Dithionate.-Sp. gr. at 11" = 2.175. Barium Dithionate.-Snturated solution boils at 102". in 0994 of water. at 11" = 3.259. 1 part dissolves in 0.692 water at 17". Rthomhic crystals, a" : 6 : c = 0.9922 : 1.0 : 0.5981. Porms occurring are czP, pm, P, p&, 00 P 00. Silver Dithiomh--ci : b : c = 0.9884 : 1.0 : 0.5811.Forms are f) 00, P, 00 P, pi, cx, Silver-sodium Dithio?zate.--ci : 6 : c = 0.9815 : 1.0 : 0.5856. Forms are F 00, P, 00 P GO, 00 P, a E m. Cleavage-plane = 00 P. Crystals are horizontally prismatic from development of dome. Potassium TritJbionate.---ci : 6 : c : L- 0.3586 : 1.0 : 0.4204. Forms are aP, 00@& m ~ m , af'a, @m. The salt is prepared by acting on a Raturated solution of potassium thiosulphate with SOz. Sodium thiosulphate similarly treated undergoes no change. Type is long prismatic. q 00 Pa. Type very short prismatic. MI. M. P. M.INORGANIC CHEMISTRY. 113 New Double Salts of Hydroxylamine. By W. MEYERINGH (Deut. Chem. Ges. Ber., x, 1946) .-Hydroxylaniine sulphate combines with aluminic, chromic, and ferric snlphates to form the following double-salts, which correspond exactly in composition and crystdine form with the alums :- (NH,0H),H2S04, A12(S04), .24aq. ; (NH20H),H2S04, Cr,(S04)., . 24aq. ; (NH20H),H2S0,, FeZ(SO4), . 24aq. 'J'he author has also obtained a double sulphate of hydroxylamine and magnesium, crystallising in long needles of the formula- Mg S Oa( NH,OH) ,H,S 046aq. J. R. Action of Neutral Sodium Phosphate on InsoIuble Carbon- ates. By A. FREBAULT and A. DESTREM (BuZl. Soc. Cl~~inz. [el, xxvii, 449-501).-The author confirms the views of Thbnard, Sou- beyran, and Lecanu, with regard t o the action of calcium phosphate on sodium carbonate, which they expla6n thus : - ~ C L L H ~ ( P O ~ ) ~ + 2Na,CO:3=2Na2HP04 + Ca2H2(P04), + 2C02 + 2H20, and not, as gener- ally represented in books, thus :-CcH4(POs)Z + 2Na2C0,2iXa2HPO4 + C&03 + H,O + C02, which reaction they shaw to be impossible, inas- much as the action of sodium phosphate on calcium carbonate gives rise to sodium carbonate and calcium phosphate. L.T. 0's. Silver-ultramarine. By KARL H E u M ANN (Deut. Chem. Ges. Ber., x, 1888--1889).-The author has isolated this compound, which is of a pure yellow colour. 11; is gradnally blackened and decomposed by boiling with solutions of sodium monosulphide and hydrosulphide, but the sodium ultramarine cannot be regenerated in this way. c. F. c. Preparation of Pure Cuprous Chloride. By R. ROTTGER (Chenz. Centr., 1877, p. 576).-An aqueous solution of cupric sulphate is saturated with sodium chloride, a small quantity of metallic copper, in the form of strips, is added, the liquid is boiled for 10 minutes, and is then filtered into cold water ; cuprous chloride precipitates as a snow- white powder. M.M. P. &I. Double Salts of Cuprous Thiosulphate. By F. R. KESSEL (Deut. Chew,. Ges, Ber., x, 1677).-0n mixing solutions of potassium thiosulphate and cupric sulphate, there is thrown down a yellow pre- cipitate, to which Rammelsberg assigned the formula K2S203.Cu2S203. The corresponding sodium salt was afterwards examined by Lene and Siewert, who found it to have $he formula Na2S20,3.Cu,S203.CuS. The author's analyses of the sodium salt prepared at 10" agrees approxi- mately with Siewert's result, but he finds that when prepared at lower temperatures the salt varies more and more in composition. Thus the atomic proportions of sodium, copper, and sulphur in the salt formed at various temperatures were the following :-114 ABSTRACTS OF CHEMICAL PAPERS.Na. Cu. S. At 10" ........ 1 : 1.35 : 2.18 ,, 0 ........ 1 : 1-35 : 1.95 ,, - 10 ........ 1 : 0.2L : 0.866 or approximately 4Na : 4Cu : 4s or Na : Cu : S. The salt, prepared at 10" is converted by cold hydrochloric acid into a white sandy powder, in which sodium, sulphur, and copper are present in the proportions-"a : S : 3Cu. This substance is perfectly stable in dry air, but is decomposed by moisture, giving off sulphur dioxide and turning brown from separa- tion of cupric sulphide. It dissolves in ammonia, forming a solution which turns blue slowly in the air. It is soluble in cold acetic acid : the solution gives with alkalis a red precipitate of cuprous oxide.Mineral acids decompose it, with separation of cupric sulphide. Strong soda-ley turns it red, separating cuprous oxide. When heated, in the dry state, it is resolved into cupric and cuprous sulphides, sodium sulphate, sulphur dioxide, and sulphur. The constitution of the substance is not yet made out. In a subsequent paper (Berichte, x, 2000) the author corrects the preceding results, and gives for the proportional numbers of atoms in the two salts the following numbers :- Na. Cu. 8. Yellow salt,. .............. 4 : 1 : 4 White salt ................ 3 : 1 : 3 the white salt being formed from the yellow by abstraction of 1 at. Na and 1 at. S. J. R. Preparation of Iron Silicofluoride. By E'R. S TO LBA (Chem. Centr., 1877, p. 385).-An aqueous solution of the salt containing a little free silicofluoric acid, is evaporated until a crust begins to form.Strong alcohol is then added so long as a precipitate is produced, the precipitated salt is collected on a funnel stopped with cotton wool, washed with strong alcohol (using the pump), and placed on a por- celain plate in a dry place. The salt as thus prepared is very stable. The corresponding salts of cobalt, nickel, and zinc may also be preci- pitated from aqueous solutions by addition of strong alcohol. M. M. P. M. Preparation of Platinum Black. Ry R. BOTTGER (Chenz. Ceritr., 187 7, p. 576).-By boiling platinic chloride solution with Rochelle salts, carbon dioxide is evolvcd and the whole of the platinum is precipitated in the finely divided state.M. M. P. M. The Working-up of Uranium Residues from Phosphoric Acid Determinations. By I?. S T R O H M E B (Dingl. polyt. J., CCXXV, 561--565).-After describing methods by Knop, Reichardt, Jani, and Gawalowsky, the author proposes to fuse the residues f o r half-an-hour with four parts of mixed sodium and potassium carbonates to whichMINERALOGICAL CHEMISTRY. 115 some charcoal has been added. An iron crucible is best, though a Hessian or porcelain one may be used. After treating with hot water and washing until free from soda, the residue is dissolved in hydro- chloric acid containing a little nitric ; and the iron and uranium are precipitated by ammonia, and separated by ammonium carbonate. J. T.110 ABSTRAflTS OF CHEMICAL PAPERS.In o rg a n i c C he m i s t r y.Combustion of Nitrogen : a Lecture-experiment.By H.KXMMERER (Veut. Chenz. Ges. Ber., x, 1684).-The direct combustionof nitrogen may be demonstrated by plungingan ignited piece of mag-nesium ribbon, 30-40 C.C. long, into a two-litre flask full of air. Afterthe experiment the presence of nitrogen tetroxide is recognisableby its odour, and by its peculiar colour after the magnesia hassettled: or it may be rendered more apparent by shaking up in theflask a solution of potassium iodide acidulated with acetic acid, andadding starch-paste, whereupon the dark-blue colour of starch iodideis produced. J. R.Combustion of Zinc and Cadmium : Lecture-experiments.By FRIDER~CH GRAMP (Dewt. Chern. Ges. Ber., x, 1684).-Tlie com-bustion of zinc may be shown i n a striking manner by compressingzinc-turnings into a loose bundle some 40 mm.long and 20 mm, indiameter, and holding one end of the bundle, by means of tongs, in agas-flame. The turnings take fire almost instantly and burn with alarge dull-green flame, giving off dense white fumes of oxide whicINORGANIC CHEMISTRY. 111speedily condenses in flocks about the room. Or a heap of zinc-turnings on an iron plate may be ignited by a gas-flame. After thecombustion there remains on the plate a large quantity of zinc oxideof a deep yellow colour while hot.Cadmium, heated in a small porcelain crucible over the blowpipe,readily takes fire and burns with a dull-red flame, emitting densebrown clouds of oxide.J. R.Apparently Anomalous Decompositions effected by CarbonicAcid. By FR. M OHR (Liehiy’s Acmalen, clxxxv, 286--295).-Theresults detailed below were obtained by passing carbon dioxide, washedwith sodium carbonate, into a flask containing solutions of the varioussubstances experimented with, until no more of the gas was absorbed,all air having been first swept out of the flask.Burium acetate (10 grams in 100 C.C. of water), when saturated withcarbon dioxide, deposited barium carbonate weighing 0.887 gyam =0.678 gram of acetic acid displaced.Calcium and strontium acetates gave no precipitate with carbondioxide.Zinc acetate (10 grams in 100 C.C. of water), when saturated withthe gas, deposited a crystalline precipitate containing 0.018 gram ofcarbon dioxide.The filtered liquid became turbid when heated, owingto decomposition of zinc bicarbonate dissolved in it.Lead acetate (10 grams in 100 C.C. of water) speedily became turbidand deposited 4.715 grams of lead carbonate. The free acetic acid inthe liquid was found by titration to amount to 1.976 grams, so that73.6 per cent. of the lead acetate employed was decomposed in theexperiment.I n the preceding cases the action of carbon dioxide may be accountedfor by the fact that insoluble carbonates are formed. But there arecases in which similar decompositions are effected, although no pre-cipitate is formed.Neictral potassium chromate ( 5 grams in 100 C.C. of water) rapidlyabsorbed an amount of carbon dioxide which, when afterwards ex-pelled by boiling and absorbed by baryta-water, gave 2.765 grams ofbarium carbonate = 0.596 grams of carbon dioxide.Borua (5 grams in 100 C.C.of water) absorbed a large quantity ofcarbon dioxide, remaining clear. The solution, after boiling, contaiiiedfree boric acid and sodium carbonate.Sodium. phosphate (10 grams in 100 c c. of water) absorbed 0.627gram of carbon dioxide, which was completely expelled by boiling.Microcosmic sa7t (10 grams in 100 c.c.) absorbed 0.631 gram ofcarbon dioxide.Sodium acetate (10 grams in 100 c.c.) absorbed 0.240 gram ofcarbon dioxide.Sodiufm a i ~ d yotnssiurn taytl-ate in aqueous solution absorbed carbondioxide, and deposited acid potassium tartrate. J. R.Purification of Hydrogen. By E u G. V A R E N N E and E w.H E R R E(BdZ. Soc. Chirn. [el, xxviii, 52:3--.524).-The gas is passed througha solution of 2 parts of potassium bichromate in 20 parts of water an112 ABSTRACTS OF CHEMICAL PAPERS.1 part of sulphuric acid, which acts as effectively as potassium per-manganate recommended by Schobig.The gas must be washed with potash to free it from traces ofacids. L. T. 0's.Preparation of Iodic Acid. By W. S T E VE N s o N (Chem. News,xxxvi, EOl).-Dissolve 2 parts baryta in 4 parts boiling water, addgradually 3 parts iodine, and filter when the solution is neutral andcolourless. The precipitated barium iodate may be decomposcd withsulphuric acid, and the liquid, after filtration, evaporated in a vacuum ;iodic acid is then obtained. The first filtrate containing barium iodidemay be used for the preparation of hydriodic acid by decomposingwith sulphuric acid.M. M. P. M.Change of Colour in certain Double Iodides. By R. BOTTGER(Clzen~. Centr., 1877, p. 2).-This change of colour, first observed byMeusel, is illustrated by the author in the following manner:-Bycoating the outside of a beaker made of tin-plate with mercuric iodideand argentic iodide (with the aid of " Cowdie pine resin " varnish)and of a second beaker with mercuric iodide and cuprous iodide, andfilling them with water of about 70" to 80" ; the yellow colour of theformer is converted into a deep orange, while the red colour of thelatter is changed t o a blackish-brown shade. By emptying thebeakers very quickly and refilling them with water of ordinary tem-perature, the original colours are reproduced.This interesting changeof colour may in this manner be repeated several times. D. B.On some Thionates. By H. BAKE R (Chem. Nezus, xxxvi, 203) .-1 part dissolvesSp. gr. at 15.5" = 4.536.Lead Dithiowute.-l part dissolves in 0.86'3 of water at 28.5". Sp. gr.Calcium Dithio?Late.--Sp. gr. at 11" = 2.176.Nickel Dithionate.-1 part dissolves in 0.897 of water at 12".Magizesiurn Dit1zionate.-Oblique prisms.Sodium Dithionate.-Sp. gr. at 11" = 2.175.Barium Dithionate.-Snturated solution boils at 102".in 0994 of water.at 11" = 3.259.1 part dissolves in 0.692water at 17".Rthomhic crystals,a" : 6 : c = 0.9922 : 1.0 : 0.5981. Porms occurring are czP, pm, P,p&, 00 P 00.Silver Dithiomh--ci : b : c = 0.9884 : 1.0 : 0.5811.Forms are f) 00,P, 00 P, pi, cx,Silver-sodium Dithio?zate.--ci : 6 : c = 0.9815 : 1.0 : 0.5856. Formsare F 00, P, 00 P GO, 00 P, a E m. Cleavage-plane = 00 P. Crystals arehorizontally prismatic from development of dome.Potassium TritJbionate.---ci : 6 : c : L- 0.3586 : 1.0 : 0.4204. Formsare aP, 00@& m ~ m , af'a, @m. The salt is prepared by actingon a Raturated solution of potassium thiosulphate with SOz. Sodiumthiosulphate similarly treated undergoes no change.Type is long prismatic.q 00 Pa. Type very short prismatic.MI. M. P. MINORGANIC CHEMISTRY. 113New Double Salts of Hydroxylamine. By W. MEYERINGH(Deut. Chem. Ges. Ber., x, 1946) .-Hydroxylaniine sulphate combineswith aluminic, chromic, and ferric snlphates to form the followingdouble-salts, which correspond exactly in composition and crystdineform with the alums :-(NH,0H),H2S04, A12(S04), .24aq. ;(NH20H),H2S04, Cr,(S04)., . 24aq. ;(NH20H),H2S0,, FeZ(SO4), . 24aq.'J'he author has also obtained a double sulphate of hydroxylamineand magnesium, crystallising in long needles of the formula-Mg S Oa( NH,OH) ,H,S 046aq. J. R.Action of Neutral Sodium Phosphate on InsoIuble Carbon-ates. By A. FREBAULT and A. DESTREM (BuZl. Soc. Cl~~inz. [el,xxvii, 449-501).-The author confirms the views of Thbnard, Sou-beyran, and Lecanu, with regard t o the action of calcium phosphateon sodium carbonate, which they expla6n thus : - ~ C L L H ~ ( P O ~ ) ~ +2Na,CO:3=2Na2HP04 + Ca2H2(P04), + 2C02 + 2H20, and not, as gener-ally represented in books, thus :-CcH4(POs)Z + 2Na2C0,2iXa2HPO4 +C&03 + H,O + C02, which reaction they shaw to be impossible, inas-much as the action of sodium phosphate on calcium carbonate givesrise to sodium carbonate and calcium phosphate.L. T. 0's.Silver-ultramarine. By KARL H E u M ANN (Deut. Chem. Ges.Ber., x, 1888--1889).-The author has isolated this compound, whichis of a pure yellow colour. 11; is gradnally blackened and decomposedby boiling with solutions of sodium monosulphide and hydrosulphide,but the sodium ultramarine cannot be regenerated in this way. c. F. c.Preparation of Pure Cuprous Chloride. By R. ROTTGER(Chenz. Centr., 1877, p. 576).-An aqueous solution of cupric sulphateis saturated with sodium chloride, a small quantity of metallic copper,in the form of strips, is added, the liquid is boiled for 10 minutes, andis then filtered into cold water ; cuprous chloride precipitates as a snow-white powder.M. M. P. &I.Double Salts of Cuprous Thiosulphate. By F. R. KESSEL(Deut. Chew,. Ges, Ber., x, 1677).-0n mixing solutions of potassiumthiosulphate and cupric sulphate, there is thrown down a yellow pre-cipitate, to which Rammelsberg assigned the formula K2S203.Cu2S203.The corresponding sodium salt was afterwards examined by Lene andSiewert, who found it to have $he formula Na2S20,3.Cu,S203.CuS. Theauthor's analyses of the sodium salt prepared at 10" agrees approxi-mately with Siewert's result, but he finds that when prepared at lowertemperatures the salt varies more and more in composition. Thus theatomic proportions of sodium, copper, and sulphur in the salt formedat various temperatures were the following :114 ABSTRACTS OF CHEMICAL PAPERS.Na. Cu.S.At 10" ........ 1 : 1.35 : 2.18,, 0 ........ 1 : 1-35 : 1.95,, - 10 ........ 1 : 0.2L : 0.866or approximately 4Na : 4Cu : 4s or Na : Cu : S.The salt, prepared at 10" is converted by cold hydrochloric acid intoa white sandy powder, in which sodium, sulphur, and copper arepresent in the proportions-"a : S : 3Cu.This substance is perfectly stable in dry air, but is decomposed bymoisture, giving off sulphur dioxide and turning brown from separa-tion of cupric sulphide. It dissolves in ammonia, forming a solutionwhich turns blue slowly in the air.It is soluble in cold acetic acid :the solution gives with alkalis a red precipitate of cuprous oxide.Mineral acids decompose it, with separation of cupric sulphide.Strong soda-ley turns it red, separating cuprous oxide. When heated,in the dry state, it is resolved into cupric and cuprous sulphides,sodium sulphate, sulphur dioxide, and sulphur. The constitution ofthe substance is not yet made out.In a subsequent paper (Berichte, x, 2000) the author corrects thepreceding results, and gives for the proportional numbers of atoms inthe two salts the following numbers :-Na. Cu. 8.Yellow salt,. .............. 4 : 1 : 4White salt ................ 3 : 1 : 3the white salt being formed from the yellow by abstraction of 1 at. Naand 1 at. S. J. R.Preparation of Iron Silicofluoride. By E'R. S TO LBA (Chem.Centr., 1877, p. 385).-An aqueous solution of the salt containing alittle free silicofluoric acid, is evaporated until a crust begins to form.Strong alcohol is then added so long as a precipitate is produced, theprecipitated salt is collected on a funnel stopped with cotton wool,washed with strong alcohol (using the pump), and placed on a por-celain plate in a dry place. The salt as thus prepared is very stable.The corresponding salts of cobalt, nickel, and zinc may also be preci-pitated from aqueous solutions by addition of strong alcohol.M. M. P. M.Preparation of Platinum Black. Ry R. BOTTGER (Chenz.Ceritr., 187 7, p. 576).-By boiling platinic chloride solution withRochelle salts, carbon dioxide is evolvcd and the whole of the platinumis precipitated in the finely divided state. M. M. P. M.The Working-up of Uranium Residues from PhosphoricAcid Determinations. By I?. S T R O H M E B (Dingl. polyt. J., CCXXV,561--565).-After describing methods by Knop, Reichardt, Jani, andGawalowsky, the author proposes to fuse the residues f o r half-an-hourwith four parts of mixed sodium and potassium carbonates to whicMINERALOGICAL CHEMISTRY. 115some charcoal has been added. An iron crucible is best, though aHessian or porcelain one may be used. After treating with hot waterand washing until free from soda, the residue is dissolved in hydro-chloric acid containing a little nitric ; and the iron and uranium areprecipitated by ammonia, and separated by ammonium carbonate.J. T