TECHNICAL CHEMISTRY. Technical Chemistry. Sodium Sulphite as a means of Removing Chlorine after Bleaching. By TIIEODOR (Ding]. polyt. J. ccix, SCHUCHARDT 154). WHEN sodium hyposulphite (thiosulphate) is used a thin film of fine!; -divided sulphur is left in the pores of the straw paper &c. which have been bleached ; this on exposure to the air becomes oxidised to sul-phuric acid which destroys the fabric by rendering it brittle. This inconvenience is avoided by the use of sodium sulphite which both yields more sulphurous acid and does not deposit sulphur. W. R. ABSTRACTS OF CHEMICAL PAPERS. Preparation of Magnesium Carbonate from Dolomite. (Dingl. polyt. J. ccjx 467.) THE process is based on the fact tha,t magnesium bicarbonate is more easily soluble in water than the corresponding calcium salt The dolomite is fiiiely ground and placed in a horizontal rotating cylinder into which carbonic anhydride obtained from calcium carbonate and hydrochloric acid is forced at a pressure of 5 or 6 atmospheres.The solution of magnesium bicarbonate is allowed to flow into a vertical cylinder into which steam is passed. The magnesium carbonate is allowed to subside and cut into squares in which form it is brought into the market. W. R. Scott’s Selenitic Mortar. By F. SCROTT (Din$. polyt. J. ccix 30-4s). IFquick-lime be slaked in water containing calcium sulphate in solu-tion the process is attended with phenomena quite different from those which are exhibited if pure water be used.The slaking is then delayed proceeds more slowly and gives a product which if mixed with a certain amount of sand forms an excellent hydraulic mortar. 2 per cent. or less of gypsum is sufficient to produce this change in the lime as to its mode of action on slaking and its properties thereafter. The same results are obtained whether burnt or unburnt gypsum is used and to the same extent. The condition of the gypsum is immaterial. For a good hjdrnulic moStar those limes are chosen which slake most slowly and upon the slaking of these the gypsum exerts the most influence as regards the delay of the phenomenon exerting but little delaying influence iipon those which immediately fall to pieces in water. The addition of the gypsurn then tends to induce the lime to harden after slaking and this hardening follows completely after addition of 1$parts by weight of gypsum to 100 parts of lime and the harden- ing tendency is not increased by further addition of the gypsum.On hardening there is a perceptible rise of temperature. The retardation of the slaking in presence of gypsum is ascribed to the fact that the lime by exertion of surface attraction becomes covered with the gypsum as with a varnish and its pores being thus filled up the delay of the hydration naturally follows. The peculiarity of certain limes which require a considerable lapse of time to disintegrate in contact with water is ascribed to the presence of certain foreign substances which produce the same retarding effect that is noticed when gypsum is present.w. s. Portland Cement from Dolomitic Limestone. By I?. ERDMENGER (Dingl. polyt. J. ccix 286-295). THEauthor concludes from his experiments that cement made from dolomitic limestone hardens under water more quickly than ordinary TECHNICAL CHEMISTRY. 97 hydraulic cement. The specific gravity of this cement when carefully prepared is not less than that of the usual Portland cement. In calcu- lating the proportion of alumina to be added the free lime alone is taken into account. The magnesia must not be regarded as equivalent to lime otherwise a product results which does not harden quickly or resist the action of water to a sufficient extent. NI. M. P. M. The Iron Ore of Bidasoa; its Treatment by Calcination and ROBRIG Lixiviation.By ERNST and ROBT.HAAS(Chem. News xxviii 220-222). SOME experiments have lately been conducted on behalf of an English company working certaiu iron mines in Spain with the view of ascer-taining whether it were ppssible in any way to remove sulphur from %he ore previous to the operation of smelting. The experiments have been fairly successful. The ores which consist principally of ‘‘ spathic carbonate ” and “brown ore,” and contain from -03 to 1.5 per cent. of sulphur were submitted to calcination and the oxidised sulphur sub- sequently removed by lixiviating or in some cases boiling the ore with water. To ascertain the limit to which the sulphur might be removed by suitable calcination and methodical lixiviation an artificially mixed ore was prepared containing 2.5 per cent.of sulphur in the form of ferric sulphide.analyses :- The results obtained are Raw ore. shown by the accompanying Calcined. Lixiviated. Iron.. ............ 43.26 51-55 53.99 Manganese ........ Sulphur .......... 2.07 2.53 2.59 0.75 2.65 0.13 An examination of the wash-water showed that it contained no iron but that sulphates of aluminium manganese calcium and magnesium had passsed into solution. J. W. Contamination of Water by Copper Pipes. By E. REICHARDT (Arch. Pharm. [3] ii 513). THEauthor points out that most waters take up more or less metal from iron and lead pipes and that copper is not in any way a better material. Water which when freshly laid on in 1859 through copper pipes contained 7.2 parts of copper in a million contained 0.8 of copper per million in 1872.Even this latter water gave a perceptibly green metallic soap. Although the quantity has diminished during the thir- teen years yet at the end of that time a most objectionable amount of copper was still taken up. C. R. A. W. The Use of Tartaric Acid in Solutions of Magnesia. By E. LEGER (Pharm. J. Trans. [3] iv 29). SINCE the introduction of citrate of magnesia into therapeutics several VOL. XXTT. H ABSTRACTS OF CHEMlCAL PAPERS. attempts more or less successful have been made to replace the citric acid in consequence of its relatively high price. When ordinary tartaric acid is used the solution at first limpid quickly becomes turbid and deposits the greater part of the salt formed.In seeking to overcome this difficulty the author has tried the various modifications of tartaric acid which are formed under the influence of heat and he finds that metatartaric acid prepared by heating tartaric acid to 170" answers perfectly. The solution of magnesium metatartrate which must be prepared with cold water will keep for seyeral weeks without alteration and as a purgative is more energetic and constant than the citrate. W. A. T. Answer to Coupier's Remarks on the Preparation of Fuchsine without Arsenic Acid. By A. BRijNrNG (Deut. Chem. Ges. Ber. vi 1072). THEauthor states that Coupier's method of preparing aniline colours without the employment of arsenic acid is-not in use in any manufactory owing to the great cost and the bad quality of the product and con- siders the circumstance that he can prepare fuchsine of good quality as cheaply as by the arsenic acid process a sufficient indication that his method is essentially different from that of Coupier.C E. G. Sausages Colotxred by Aniline. By E. REICHARDT (Arch. Pharm. [3] 3 574). THEuse of fuchsine to give to inferior soluble materials the tint which ought to be due only to the colouring matters of blood is of very fre- quent occurrence. Sausage meat thus tinted may be distinguished by digesting the finely divided substance with alcohol or ether whereby aniline colours are dissolved giving the usual tinted solutions. Blood colouring matters on the contrary7 are not thus dissolved.By con-trasting the quantity of normal soda-solution required to bleach the colouring matter extracted from a given weight of sausage with that requisite for a dilute fuchsine solution of known shength an approxi- mate notion of the amount of aniline colour present can be obtained. Thus the author estimated that one sample contained 0.005 gram fuchsine per kilogram of meat. Apart from the unknown biit probably ixijurious physiological action of the fuchsine itself when habitually thus consumed the practice of tintling sausages in this way is to be condemned as it enables much adulteration with inferior and paler silbstances to be carried on and it is always liable to introduce arsenic into the sjstem a result to be objected to even though the quantity actually present in a kilogram of meat may be SO small as not to be readily detected.C. R A. W. TECHNICAL CHEMISTRY. A Method of Preparing the Fur of Rabbits and Hares for the Manufacture of Felt without the use of Mercury. By HIr,r.AEItET. Note by TON DELPECH (J. Pharm. Chirn. [4] xvii 453; Dingl. polyt. J. ccix 230-234). THEfur used for the manufacture of felt is soaked in a solution of mercurous nitrate in nitric acid which alters the structure of the indi- vidual hairs changing the form of the cells diminishing their size and rendering them transparent. Hillaeret has found that thisis due to the action of the nitrous acid evolved by the mercurous nitrate. The action of mercury is hurtful to the workmen employed as their hands are frequently immersed in the solution and they breathe mercurial vapours when the fur is drying.Instead of mercury a saccharine substance such as molasses may be used together with nitric acid. The latter is reduced to nitrous acid and produces the desired change. Greater difficulty is experienced in washing the felt but this is counterbalanced by the absence of danger to the workman. w. R. Cadmium Sulphide in a Pasty Condition. (Dingl. pol$ J. ccix 315.)-Sulphide of cadmium finds a technical application in com-municating a yellow colour to soap. It may be obtained rubbed up with oil in which form it may be more easily diffused through the eoap. W. R. A Red Ink which Resists the Action of most Chemicals. (ibid. 316.)-This ink is a solution of carmine in soluble glass and must be kept in a bottle with a well oiled cork.W. R. Safranin. (ibid.,316.)-Crude commercial safranine may be puri-fied by treatment with alcohol and presents the appearance of a greenish powder with metallic lustre. It can be used for dyeing without a mop- dant and when a small portion is treated alternately with concentrated sulphuric acid and water numerous brilliant colours are produced. W. R. Spontaneous Ignition of Hay. (ibid.,ix 318.)-H. Ranke ob- served an interesting case of the above. A haystack 23 feet in length 23 in breadth and 16 in height emitted zt smell of burning. On removing the hay from the top at a depth of 5 feet in the middle of the stack sparks were noticed which burst into flame.The flame was rapidly extinguished with water. The interior of the stack was carbonised and the carbonaceous residue on heating to 300" in an oil-bath ignitsd spontaneously on exposure to the air. W. R. Gum Arabic of Strong Adhesive Power (Vegetable Glue). (ibid. 320.)-It is a well-known fact that gum arabic will not cause ABSTRACTS OF CHEMICAL PAPERS. blotting-papw to adhere. This may be remedied by adding to 250 grams of the concentrated solution 2 grams of aluminium sul-phate. Alum answers also but not so well. W. R. Testing for Carbonic Acid in Magnesia and Zinc Oxide. By H. CALMBERG; (Dingl. polyt. J. ccix 154).--Care must be taken that all air be expelled by rubbing up the oxides with water in a mortar and warming gently before adding an acid.W. R. Dialysed Iron Oxide as a Mordant in Dyeing. (ibid. ccix 465.)-Ferric oxide is used as a mordant in dyeing. The large amount of acid necessary for its solution acts injuriously on the fabric especially on silk ;this excess of acid may be removed by dialysing the acid solution of ferric chloride. W. R. New Process in the Preparation of Anthracene. (ibid. 466.) -The yield of anthacene from heavy oil may be increased from 10 to 15 per cent. by the use of stirrers in the retorts from which it is distilled. W. R. A Reddish-Brown Paint for Wood. (ibid.,466.)-The wood is first washed with a solution of 1 lb. cupric sulphate in 4 litres of water and then with 3 lb. potassium ferrocyanide dissolved in 4 litres of water.The resulting brown cupric ferrocyanide withstands the weather and is not attacked by insects. It may be covered if desired with a coat of linseed oil 'varnish. w. a. Porosity of Porcelain. (ibid, 468.) -Salvetat has noticed that if unglazed porcelain be allowed to lie in a solution of colouring matter the interior becomes impregnated with the colour while the outsside remains white. By transmitted light however the colour may be made apparent. This property may be employed in ornamenting their porcelain vessels. W. R. The Purification and Utilisation of Sewage. By R. B. GRANTHAM (Chemical News xxviii 163). The Sewage of Manufacturing Towns. By W. T.MCGOWEN (Chemical News xxviii 184).