NEWS its complete expulsion may not prove easy. The Sydney, authorities do not seem favourably disposed towards irrigation. It must be admitted, on the one hand, that in so comparatively dry a climate as that of Australia this method of dealing with sewage seems more feasible, from an economical point of view, than under the cloudy and drizzling skies of England; but, on the other hand, the danger to health will undoubtedly rise with the average temperature. We scarcely understand the precipitation scheme recommended at Sydney. The material to be employed is the carbonaceous residue from certain shales employed in the manufacture of kerosene oil. We can readily see how this matter might form a useful filter-bed, or how it might be employed as an adjunct in a precipitation process; but we are not aware that it contains any principle capable of acting as a true precipitant. Practical Manual of Chemical Analysis and Research applied to the Arts and Manufactures.* By P. A. BOLLEY and E. KOPP. Second French Edition, revised and enlarged. Translated from the Fourth German Edition, by Dr. L. GAUTIER. Parts 3 and 4. Paris: F. Savy. THIS Manual is more extensive in its scope than any similar work in the English language. With the exception of purely pharmaceutical products it embraces every class of substances which are likely to fall into the hands of the commercial analyst or the "works-chemist." But as the entire book does not greatly exceed one thousand pages, we need not be surprised if some bodies are disposed of rather briefly, whilst others are treated at a disproportionate length. Thus alcoholic liquids occupy nearly one hundred pages, whilst soils and manureswhich in this country certainly occupy a much larger share of the attention of analytical chemists-take up merely forty-two. In treating of the determination of phosphoric acid in manures and phosphatic minerals, the authors declare their conviction that of all known methods the molybdic acid process alone is capable of a general application, and yields results really trustworthy. All the other methods described, gravimetric or volumetric, are inexact or very tedious, on account of the presence of iron ör alumina. The authors decide, contrary to the view of Birnbaum and Chojnacki, that nitric acid cannot be safely used as a solvent in the analysis of mineral phosphates, as notable quantities of phosphoric acid remain undissolved in the residue. They recommend hydrochloric acid when the presence of iron in the solution can occasion no difficulty, as when the molybdic method is to be used. In other cases Graham's solvent-sulphuric acid diluted down to 5 per cent of the monohydrate-may be advantageously employed. For determining "reverted" phosphoric acid in manures they prefer the indirect method-ascertaining the total phosphoric acid insoluble in water, and deducting from this quantity the phosphoric acid insoluble in citrate of ammonia. In treating on aræometry the authors strongly recommend Twaddle's hydrometer, in preference to those of Baumé and Beck, so much employed upon the Continent, and which are as devoid of any rational foundation as is the English system of weights and measures. In the examination of magenta for sugar-an occasional adulteration-it is recommended to withdraw the colouring matter from the solution by means of wool or silk, or to precipitate it with common salt. The sugar then remains in solution, and may be easily recognised, and, if needful, determined. The directions for the examination of lac-dye are somewhat insufficient. For certain uses, as in dyeing stuffs which require to be hot-pressed, it is very important that lac-dye should contain a minimum of gum-lac, for the approximate estimation of which the authors give no in "Manuel Pratique d'Essais et de Recherches Chimiques appliqués aux Arts et a l'Industrie." structions. In treating of cochineal and indigo no allusion is made to the specific gravity of the samples, the determination of which is an easy and rapid way of detecting mineral impurities, whether accidental or intentional. Light cochineals and indigos may certainly be bad, but heavy ones cannot be good. Flavin appears to have been entirely overlooked, and the extracts of the dyewoods are spoken of merely in the solid state in which they are so often met with on the Continent, and not in the liquid form prevalent in England. The preparation of extracts, we may here observe, is one of the branches of manufacturing chemistry in which England is now not holding her own. Very considerable quantities both of French and American extracts are now used in Lancashire. The tables showing the reactions of colouring-matters -natural, artificial, and when fixed upon textile fibresare very complete. As regards the coal-tar colours, the authors have in many instances taken the useful precaution of giving the name of the manufacturer, often the only method of identifying the exact substance in question. The least satisfactory portion of the work is the section on milk, which is altogether out of date, and in which much space is devoted to those deplorable instruments the lactometer and the creamometer. The book will form a useful addition to the library of reference of the analytical chemist. CORRESPONDENCE. ROSE COLOUR OBSERVED IN THE MANUFACTURE OF CHLORATE OF POTASH. To the Editor of the Chemical News. SIR,-The following facts may throw some light upon the origin of the "rose" or red-violet colour observed in the course of manufacture of chlorate of potash, as noticed in Dr. Hofmann's "Report" &c. (CHEM. NEWs, vol. xxxiv., p. 139). Nearly all commercial samples of chloride of lime give, when boiled with distilled water, a splendid violet-red solution; on filtering through paper the colour disappears, and the paper is stained brown: if it be removed from the funnel, washed from adhering chloride of lime, and moistened with pure strong hydrochloric acid, the stain disappears, and a yellow solution is formed, which gives the characteristic iron-reactions with ferrocyanide and sulphocyanide of potassium. The purple solution may be obtained clear by subsidence, and may then be drawn off with a pipette; it may be evaporated nearly to dryness on the water-bath without decomposition, but on applying a somewhat stronger heat, to drive off the last traces of moisture, the coloured compound is decomposed, and the mass acquires a brown tinge. If alcohol be added to the clear coloured solution a blue shade is first developed, and afterwards the colour gradually fades into a faint brown. To determine the question of the presence of manganese, one drop of the coloured solution was placed on white filtering-paper, which was then dried on the waterbath; a brown stain appeared where the liquid had been : this was cut out, and divided into two parts; one of them was moistened with hydrochloric acid, and drops of ferrocyanide and sulphocyanide of potassium placed on opposite sides of the moistened portion; strong iron reactions were obtained in each case. The other portion of the stained paper was incinerated and fused on platinum-foil with a little carbonate of soda; no trace of the manganese reaction could be observed with this most delicate test, It is evident, therefore, that in the case in question the colour of the solution of chloride of lime is due to iron, not to manganese, and it would seem most probable that the coloured compound is a lime-salt of ferric acid: this would account for the appearance of the colour where Deacon's process for the preparation of chlorine is used, since traces of iron could hardly be excluded from any process of chlorine manufacture.' It is to be noted that no colour is produced where the "chloride" is exhausted with cold water; a temperature at or near the boiling-point is necessary to the appearance of the phenomenon.-I am, &c., THOS. P. BLUNT, M.A. Oxon., F.C.S. Tower Place, Shrewsbury, October 3, 1876. DETERMINATION OF GOLD IN PYRITES. To the Edtior of the Chemical News. SIR,-Referring to a letter which appeared in the CHEMICAL NEWS (vol. xxxiv., p. 151), signed by Mr. Wanklyn, we ask your permission to make a short statement as follows:We beg to say that we are members of the Committee of Publication of the Analyst; that we consider we have devoted a fair amount of attention to our duties; that we have no wish to shirk our responsibility for anything that has appeared in the Analyst; and consequently we are in a position to deny-as we hereby emphatically do-Mr. Wanklyn's assertion that two other members of the Committee of Publication " alone are responsible for the contents of the paper." Whatever may be Mr. Wanklyn's view of the duty of anyone holding office, we for ourselves can say that unless we felt ourselves both able and willing to perform our share of the duties of the Publication Committee of the Analyst we would certainly not allow our names to be published as members of that committee.-We are, &c., CHAS. HEISCH. A. DUPRE. October 9, 1876. BLOWPIPE ANALYSIS OF THE NEW MINERAL HENWOODITE. To the Editor of the Chemical News. It was taught to every student at Freiberg, and I have sent. HENWOODITE. To the Editor of the Chemical News. SIR,—Allow me to write a few lines in reply to Major Ross's remarks on my blowpipe experiments with Henwoodite. He says that by the methods I employed "the iron present is not detected at all." The reason I did not find any iron is simply this-there was probably none preI took great care to use very pure fragments of the mineral, examining each one minutely with a lens before testing it; and my friend Mr. J. H. Collins informs me that when he tested some pure specimens with sulphocyanide of potassium, he was unable to detect the presence of iron. Major Ross admits that his specimens, even after his beginning to test them, were mixed with Göthite (? Limonite), and I cannot help surmising that the iron he detected was simply a mechanical impurity. Had there been much iron present I should not have obtained a blue bead with borax (cold). Besides, the precipitate with ammonia would have revealed its presence. I cannot lay claim to the " great sagacity" with which Major Ross credits me for suspecting the presence of P205 in Henwoodite. The association of that mineral with Chalkosiderite, a hydrated phosphate of iron and copper, and its globular form, would naturally lead any mineralogist to test for phosphoric acid. One word more :—Major Ross's "new test for cupric phosphate " seems to me to be merely a modification of Berzelius's good old method, which has been known for more than fifty years.* Berzelius used metallic lead, which is found in every complete blowpipe case, whilst Major Ross employs the oxide. The new method requires an additional, and it appears to me unnecessary, reagent. In conclusion, let me assure you that I would not on any account undervalue Major Ross's labours; on the contrary, I congratulate him on having discovered many new and original tests in the too much neglected art of blowpipe analysis.-I am, &c., Truro, October 16, 1876. CLEMENT LE NEVE FOSTer. SOURCES. SIR,-Under the above heading (CHEM. NEWS, vol. xxxiv., CHEMICAL NOTICES FROM FOREIGN p. 156) Major Ross gives an account of his examination, by his new methods, of Henwoodite. The following passage occurs in his article: 66 (6.) Heated another piece of (1), with pure oxide of lead, on a charcoal mortar on aluminium plate. Fused with great effervescence to a crystalline mass of plumbic phosphate, with minute balls of copper interspersed. (This new test for cupric phosphate is best seen with Libethenite: the copper disengaged seems beautifully pure)." This is a very interesting and characteristic reaction, but it is most certainly not new, as Major Ross asserts it to be. On the contrary, it is very old, and very well known to everybody who has practised the use of the blowpipe to any extent. If Major Ross will obtain a copy of Plattner's book on the Blowpipe, he will find the test fully described (the copy now before me is the German edition of 1865), and learn that it was given first by Berzelius. NOTE.-All degrees of temperature are Centigrade, unless otherwise expressed. Comptes Rendus Hebdomadaires des Seances, de l'Acadenie des Sciences. No. 13, September 25, 1876. Probable Consequences of the Mechanical Theory of Heat.-M. Le Général Favé.-The substance which fills space, and which we call ether, without knowing whether it is simple or multiple, transmits the solar heat to the planets. This heat is a vibratory movement which the ether communicates to ponderable matter, and which has a speed of translation so considerable that we may ask if the heat coming from the sun does not exert a re. *Berzelius," Anwendung des Löthrohrs," p. 164. Nümberg, 18a1. NEWS pulsive force upon each planet. Transparent bodies are traversed by radiant heat in a greater or less degree. That is, the vibratory movements of the ether intercommunicate in the whole interior of the transparent body without being transmitted, at least directly to the ponderable matter. Thus, transparent bodies are constituted with ether interposed in their interstices. It is known that a body which has passed from the solid to the liquid state, or from the liquid to the gaseous, has absorbed latent heat, and yet the molecules doubtless have not changed their vibratory speed when the solid, liquid, or gas have been brought to the same temperature. What, then, is the latent heat, that is to say, the movement in sensible to the indications of the thermometer? We believe that everything may be explained; that the liquid contains, to a larger degree than the solid, interposed ether, which vibrates in unison with the ponderable matter. On this hypothesis, the gas would contain yet more constitutive ether than the liquid. The transparence of liquids, and the facility with which gases give passage to radiant heat, are facts favourable to this explanation. Photo-micrographic Researches on the Effects of the Reduction of Salts of Silver in Photographic Proofs.-M. J. Girard.-On examining under a strong magnifying power a negative proof developed indistinctly with sulphate of iron or pyrogallic acid, we remark almost invariably in the light portions not acted upon, crystals uniformly disseminated, scarcely 1-100 of a m.m. in size. These crystals of reduced iodide of silver, sometimes very abundant, are the cause of frequent failures, as they form a cloud impervious to light. New Process for the Extraction of Gallium.-M. Lecoq de Boisbaudran.-The ore, according to its nature, is dissolved in aqua regia, hydrochloric or sulphuric acid. The cold liquid is treated with plates of zinc, and filtered, when the escape of hydrogen is still considerable. The liquid is then heated with a large excess of zinc. The gelatinous deposit is washed, and redissolved in hydrochloric acid. The new liquid is heated with an excess of zinc, and a second gelatinous precipitate is obtained. Into the hydrochloric solution of this second precipitate formed by zinc a current of sulphuretted hydrogen is passed, the liquid is filtered, the excess of sulphuretted hydrogen driven off, and it is fractionated with carbonate of soda, ceasing when the ray Gau 4170 ceases to be visible with the hydrochloric solution of the precipitate. The oxides or sub-salts are taken up with sulphuric acid; the solution is carefully evaporated until white sulphuric acid vapours are no longer, or but slightly, given off. It is let cool, and stirred with water, which dissolves the mass after the lapse of a time varying from some hours to a couple of days. The solution of the sulphate almost neutral is diluted with much water, and raised to a boil. The sub-salt of gallium is separated by filtration whilst hot. This basic salt is dissolved in a little sulphuric acid, and the liquid is mixed with a slight excess of caustic potassa, so as not (?) to dissolve the gallium, but to leave the iron. It is filtered, and the oxide of gallium is precipitated by a prolonged current of carbonic acid. This oxide is re-dissolved in a minimum of sulphuric acid, a slight excess of acetate of ammonia, feebly acid, is added, and it is then treated with sulphuretted hydrogen. Under these conditions the gallium is not precipitated. acetic liquid is filtered, diluted with water, and raised to a boil. The bulk of the gallium is precipitated and filtered whilst hot. The mother-liquor, concentrated, and boiled with aqua regia in order to destroy ammoniacal salts, is added to the other gallium residues. The precipitate formed on heating the acetic liquid is re-dissolved in sulphuric acid, a slight excess of caustic potassa is added, and it is then filtered. The potassic solution is electrolysed. The gallium is easily detached from the sheet of platinum on pressing it between the fingers under warm water. The metal is then immersed for about half an hour in nitric acid at about 60° or 70°, quite free from The chlorine, and diluted with an equal volume of water. After washing it may be regarded as pure. Moniteur Scientifique, du Dr. Quesneville, September, 1876. Schunck and H. Roemer.-These authors have announced Anthraflavic and Iso-anthraflavic Acids. MM. E. in an earlier memoir the discovery of an acid isomeric with the anthraflavic, to which they have given the name of isoanthraflavic acid, and which is prepared as follows:The crude material prepared by Mr. Perkin is obtained on precipitating with hydrochloric acid a solution derived is first separated from anthraquinon by dissolving the precipitate in dilute soda-lye: the filtrate yields, on the addition of hydrochloric acid, a yellow precipitate, which is partly dissolved in cold baryta-water. The blood-red solution is precipitated by acids in green flocks, turning red. This precipitate, if repeatedly crystallised from alcohol, gives a substance which forms yellow needles, and which, if dried at 150°, yields on analysis the following results : from the treatment of crude alizarin with lime-water. It Calculated for CHO 70'00 3'33 Isoanthraflavic acid crystallises with water; a portion evaporates on desiccation over sulphuric acid, but the crystals preserve their lustre unless heated to 120°. The authors have also analysed the barium salt which corresponds to the formula C14H6BaO4. baryta-water (see above) is composed of anthraflavic acid. Anthraflavic Acid. The portion insoluble in cold The barium salt of this acid closely resembles the corresponding salt of isoanthraflavic acid, but it is insoluble. It Crystallises with two molecules of water, and is gradually decomposed on exposure to the air. Properties of Isoanthraflavic and Anthraflavic Acids, Carbonic acid throws down anthraflavic acid from the aqueous solution of the barium salt, but the salt is re-formed on ebullition. Soluble in alcoholic lead acetate. The solutions in alkalies and alkaline earths are of an intense red. Sublimes in brilliant yellow needles and leaflets. Anthraflavic Acid. Crystallises without water. Ditto. Ditto. Ditto. sulphuric acid with a yellow. Soluble in concentrated Insoluble in cold baryta water. Soluble with difficulty in cold lime-water, and less soluble at a boil. Ditto. Ditto. The solutions in alkalies and alkaline earths are more or less tinged with reddish yellow. Ditto. Ditto. Is not fixed by mordants. The authors have examined the tetrabromated isoanthraflavic acid, the corresponding anthraflavic compound, and the diacetylic, diethylic, and dimethylic derivatives of the two acids.-Berichte der Deutschen Chemischen Gesellschaft zu Berlin. the coloured compound is a lime-salt of ferric acid: this would account for the appearance of the colour where Deacon's process for the preparation of chlorine is used, since traces of iron could hardly be excluded from any process of chlorine manufacture. It is to be noted that no colour is produced where the "chloride" is exhausted with cold water; a temperature at or near the boiling-point is necessary to the appearance of the phenomenon.-I am, &c., THOS. P. BLUNT, M.A. Oxon., F.C.S. To the Edtior of the Chemical News. SIR,-Referring to a letter which appeared in the CHEMICAL NEWS (vol. xxxiv., p. 151), signed by Mr. Wanklyn, we ask your permission to make a short statement as follows:We beg to say that we are members of the Committee of Publication of the Analyst; that we consider we have devoted a fair amount of attention to our duties; that we have no wish to shirk our responsibility for anything that has appeared in the Analyst, and consequently we are in a position to deny as we hereby emphatically do-Mr. | Wanklyn's assertion that two other members of the Committee of Publication" alone are responsible for the contents of the paper." Whatever may be Mr. Wanklyn's view of the duty of anyone holding office, we for ourselves can say that unless we felt ourselves both able and willing to perform our share of the duties of the Publication Committee of the Analyst we would certainly not allow our names to be published as members of that committee.-We are, &c., CHAS. HEISCH. A. DUPRÉ. October 9, 1876. BLOWPIPE ANALYSIS OF THE NEW MINERAL HENWOODITE. To the Editor of the Chemical News. It was taught to every student at Freiberg, and I have seen it used very frequently there and elsewhere. It is certainly new to use oxide of lead for the test, the usual method being to fuse the mineral with a piece of metallic lead. The use of oxide serves no good purpose, and has no object whatever; it only increases very unnecessarily the "great effervescence" of which Major Ross speaks. It is quite correct of Major Ross to state that the test is best seen with Libethenite; and if he will look under that mineral in Dana's "Mineralogy" he will find the reaction fully described.—I am, &c., H. M. W. HENWOODITE. To the Editor of the Chemical News. SIR,-Allow me to write a few lines in reply to Major Ross's remarks on my blowpipe experiments with Henwoodite. He says that by the methods I employed "the iron present is not detected at all." The reason I did not find any iron is simply this-there was probably none present. I took great care to use very pure fragments of the mineral, examining each one minutely with a lens before testing it; and my friend Mr. J. H. Collins informs me that when he tested some pure specimens with sulphocyanide of potassium, he was unable to detect the presence of iron. Major Ross admits that his specimens, even after his beginning to test them, were mixed with Göthite (? Limonite), and I cannot help surmising that the iron he detected was simply a mechanical impurity. Had there been much iron present I should not have obtained a blue bead with borax (cold). Besides, the precipitate with ammonia would have revealed its presence. I cannot lay claim to the "great sagacity" with which Major Ross credits me for suspecting the presence of P2O5 in Henwoodite. The association of that mineral with Chalkosiderite, a hydrated phosphate of iron and copper, and its globular form, would naturally lead any mineralogist to test for phosphoric acid. One word more :-Major Ross's "new test for cupric phosphate" seems to me to be merely a modification of Berzelius's good old method, which has been known for more than fifty years.* Berzelius used metallic lead, which is found in every complete blowpipe case, whilst Major Ross employs the oxide. The new method requires an additional, and it appears to me unnecessary, reagent. In conclusion, let me assure you that I would not on any account undervalue Major Ross's labours; on the contrary, I congratulate him on having discovered many new and original tests in the too much neglected art of blowpipe analysis.—I am, &c., Truro, October 16, 1876. CLEMENT LE NEVE FOSTER. SIR,-Under the above heading (CHEM. NEWS, vol. xxxiv., CHEMICAL NOTICES FROM FOREIGN p. 156) Major Ross gives an account of his examination, by his new methods, of Henwoodite. The following passage occurs in his article: (6.) Heated another piece of (1), with pure oxide of lead, on a charcoal mortar on aluminium plate. Fused with great effervescence to a crystalline mass of plumbic phosphate, with minute balls of copper interspersed. (This new test for cupric phosphate is best seen with Libethenite: the copper disengaged seems beautifully pure)." This is a very interesting and characteristic reaction, but it is most certainly not new, as Major Ross asserts it to be. On the contrary, it is very old, and very well known to everybody who has practised the use of the blowpipe to any extent. If Major Ross will obtain a copy of Plattner's book on the Blowpipe, he will find the test fully described (the copy now before me is the German edition of 1865), and learn that it was given first by Berzelius. SOURCES. NOTE.-All degrees of temperature are Centigrade, unless otherwise expressed. Comptes Rendus Hebdomadaires des Seances, de l'Academie des Sciences. No. 13, September 25, 1876. Probable Consequences of the Mechanical Theory of Heat.-M. Le Général Favé.-The substance which fills space, and which we call ether, without knowing whether it is simple or multiple, transmits the solar heat to the planets. This heat is a vibratory movement which the ether communicates to ponderable matter, and which has a speed of translation so considerable that we may ask if the heat coming from the sun does not exert a re. * Berzelius," Anwendung des Löthrohrs," p. 164. Nümberg, 1821. NEWS pulsive force upon each planet. Transparent bodies are traversed by radiant heat in a greater or less degree. That is, the vibratory movements of the ether intercommunicate in the whole interior of the transparent body without being transmitted, at least directly to the ponderable matter. Thus, transparent bodies are constituted with ether interposed in their interstices. It is known that a body which has passed from the solid to the liquid state, or from the liquid to the gaseous, has absorbed latent heat, and yet the molecules doubtless have not changed their vibratory speed when the solid, liquid, or gas have been brought to the same temperature. What, then, is the latent heat, that is to say, the movement insensible to the indications of the thermometer? We believe that everything may be explained; that the liquid contains, to a larger degree than the solid, interposed ether, which vibrates in unison with the ponderable matter. On this hypothesis, the gas would contain yet more constitutive ether than the liquid. The transparence of liquids, and the facility with which gases give passage to radiant heat, are facts favourable to this explanation. Photo-micrographic Researches on the Effects of the Reduction of Salts of Silver in Photographic Proofs.-M. J. Girard.-On examining under a strong magnifying power a negative proof developed indistinctly with sulphate of iron or pyrogallic acid, we remark almost invariably in the light portions not acted upon, crystals uniformly disseminated, scarcely 1-100 of a m.m. in size. These crystals of reduced iodide of silver, sometimes very abundant, are the cause of frequent failures, as they form a cloud impervious to light. New Process for the Extraction of Gallium.-M. Lecoq de Boisbaudran.-The ore, according to its nature, is dissolved in aqua regia, hydrochloric or sulphuric acid. The cold liquid is treated with plates of zinc, and filtered, when the escape of hydrogen is still considerable. The liquid is then heated with a large excess of zinc. The gelatinous deposit is washed, and redissolved in hydrochloric acid. The new liquid is heated with an excess of zinc, and a second gelatinous precipitate is obtained. Into the hydrochloric solution of this second precipitate formed by zinc a current of sulphuretted hydrogen is passed, the liquid is filtered, the excess of sulphuretted hydrogen driven off, and it is fractionated with carbonate of soda, ceasing when the ray Gaa 4170 ceases to be visible with the hydrochloric solution of the precipitate. The oxides or sub-salts are taken up with sulphuric acid; the solution is carefully evaporated until white sulphuric acid vapours are no longer, or but slightly, given off. It is let cool, and stirred with water, which dissolves the mass after the lapse of a time varying from some hours to a couple of days. The solution of the sulphate almost neutral is diluted with much water, and raised to a boil. The sub-salt of gallium is separated by filtration whilst hot. This basic salt is dissolved in a little sulphuric acid, and the liquid is mixed with a slight excess of caustic potassa, so as not (?) to dissolve the gallium, but to leave the iron. It is filtered, and the oxide of gallium is precipitated by a prolonged current of carbonic acid. This oxide is re-dissolved in a minimum of sulphuric acid, a slight excess of acetate of ammonia, feebly acid, is added, and it is then treated with sulphuretted hydrogen. Under these conditions the gallium is not precipitated. acetic liquid is filtered, diluted with water, and raised to a boil. The bulk of the gallium is precipitated and filtered whilst hot. The mother-liquor, concentrated, and boiled with aqua regia in order to destroy ammoniacal salts, is added to the other gallium residues. The precipitate formed on heating the acetic liquid is re-dissolved in sulphuric acid, a slight excess of caustic potassa is added, and it is then filtered. The potassic solution is electrolysed. The gallium is easily detached from the sheet of platinum on pressing it between the fingers under warm water. The metal is then immersed for about half an hour in nitric acid at about 60° or 70°, quite free from The chlorine, and diluted with an equal volume of water. After washing it may be regarded as pure. Moniteur Scientifique, du Dr. Quesneville, Schunck and H. Roemer.-These authors have announced Anthraflavic and Iso-anthraflavic Acids.-MM. E. in an earlier memoir the discovery of an acid isomeric with the anthraflavic, to which they have given the name of isoanthraflavic acid, and which is prepared as follows:precipitating with hydrochloric acid a solution derived The crude material prepared by Mr. Perkin is obtained on from the treatment of crude alizarin with lime-water. It is first separated from anthraquinon by dissolving the precipitate in dilute soda-lye: the filtrate yields, on the addition of hydrochloric acid, a yellow precipitate, which is partly dissolved in cold baryta-water. The blood-red solution is precipitated by acids in green flocks, turning red. This precipitate, if repeatedly crystallised from alcohol, gives a substance which forms yellow needles, and which, if dried at 150°, yields on analysis the following results: Calculated for C1HO 70'00 3'33 Isoanthraflavic acid crystallises with water; a portion evaporates on desiccation over sulphuric acid, but the crystals preserve their lustre unless heated to 120°. The authors have also analysed the barium salt which corresponds to the formula C14H6BаO4. baryta-water (see above) is composed of anthraflavic acid. Anthraflavic Acid. The portion insoluble in cold The barium salt of this acid closely resembles the corresponding salt of isoanthraflavic acid, but it is insoluble. It crystallises with two molecules of water, and is gradually decomposed on exposure to the air. Properties of Isoanthraflavic and Anthraflavic Acids, Isoanthraflavic Acid. Crystallises from aqueous alcohol with water. crystalline Melting-point above 330°. Less soluble in glacial acetic acid than in alcohol. Almost insoluble in ben zol, chloroform, and ether. Soluble in hot concentrated sulphuric acid with a deep red. Easily soluble in cold baryta-water. Easily soluble in lime water. Carbonic acid throws down anthraflavic acid from the aqueous solution of the barium salt, but the salt is re-formed on ebullition. Soluble in alcoholic lead acetate. The solutions in alkalies and alkaline earths are of an intense red. Sublimes in brilliant yellow needles and leaflets. Anthraflavic Acid. Crystallises without water. Ditto. Ditto. Ditto. Soluble in concentrated sulphuric acid with a yellow. Insoluble in cold baryta water. Soluble with difficulty in cold lime-water, and less soluble at a boil. Ditto. Ditto. The solutions in alkalies and alkaline earths are more or less tinged with reddish yellow. Ditto. Ditto. Is not fixed by mordants. The authors have examined the tetrabromated isoanthraflavic acid, the corresponding anthraflavic compound, and the diacetylic, diethylic, and dimethylic derivatives of the two acids.-Berichte der Deutschen Chemischen Gesellschaft zu Berlin. |