merce is a mixture of several triamidotriphenyl derivatives; its hydrochloric acid solution gives a green coloration with potassium chlorate. The above homologues of pararosaniline do not give this reaction. Acid violet dyes closely related to Formyl violet are formed by sulphonating ethylbenzylaniline and condensing it with formaldehyde into diethyldibenzyldiamido-diphenylmethanedisulphonic acid, oxidising the latter and condensing the resulting hydrol base with tertiary aromatic bases and again oxidising. Acid violet 4 BN of the Badische Anilin und Soda Fabrik is the sodium salt of benzylpentamethylpararosaniline sulphonic acid (Eng. Pat. 21,284, 1890; this Journal, 1891, 1033), and apparently identical with Acid violet 6 B of the Farbenfabriken vormals Fr. Bayer and Co., which, however, is prepared by a different method. The Acid violet 6 B of the Berlin Actiengesellschaft is obtained by oxidation of the condensation product of dimethyl-pamidobenzaldehyde and ethylbenzylaniline sulphonic acid. Formyl violet 4 SB of the firm of Cassella and Co. is dibenzyltetra-ethyltriamidotriphenylcarbinoldisulphonic acid. While its fastness to light is similar to that of the above acid violets, it is superior to these in its resistance to alkalis and milling. It dyes very evenly and can, therefore, be advantageously used for pale shades in wool dyeing or printing. In concentrated sulphuric acid this dye dissolves with a brownorange colour, which becomes blue-violet on addition of water; alkalis decolorise the aqueous solution. Acid violet 6 BN of the Badische Co. yields shades resembling those of Acid violet 7 B, and is as fast to light as Formyl violet. It dyes wool slowly, best at a temperature of 72°-75°. Sulphuric acid dissolves it with a red-brown colour, which becomes successively blue and violet on dilution with water. Acid violet 5 B of the Elberfeld Farbenfabriken dyes very well, like all the other acid dyes, in a bath containing sodium bisulphate, the baths being exhausted at 67. The dyed colour is moderately stable to milling and light. The Fast acid violet 10 B of the same firm, dyes wool bright violetblue colours and is very suitable for dyeing compound shades along with phenolic and other acid dyes. It is best applied at 75°-80°. It possesses a considerable degree of fastness to light and milling. In sulphuric acid this dye dissolves with a yellow colour which on the addition of water becomes first green and then blue. The Fast acid violets A, 2 R, R, and B, of the Farbwerke vormals Meister, Lucius, and Brüning, are sodium salts of sulphophenylated and -tolylated rhodamines. They may be applied either substantively (in an acid bath) or on chrome-mordanted wool, yielding bright colours which are fairly fast to light, stoving, alkalis, &c. Victoria violet 4 BS, of the same firm, is a moderately bright blue-violet, which is applied on wool in an acid bath. The shades it yields do not lose much in milling but possess little resistance towards light. The An interesting group of hydroxy- and carboxy- amido derivatives of triphenylmethane is obtained by condensing tetramethyldiamidobenzhydrol with resorcinol, pyrogallol, a- and B-naphthol, dihydroxynaphthalene, &c., and oxidising the products (Eng. Pat. 14,621, 1890; this Journal, 1891, 761). The dyes thus formed have an affinity for the chrome mordant and are suitable for wool dyeing but more especially for calico printing. Chrome-violet, one of the group, is sent into commerce as a bronzy-blue paste, which dissolves in sulphuric acid with a yellow-brown colour, turning dark red on dilution; in acetic acid with a brilliant green colour. In the case of wool, it is best applied in a bath containing acetic acid on material mordanted with potassium bichromate and oxalic acid, 2.5 per cent. of the dye giving a pale, and 10 per cent. a rich mauve shade. Chrome-blue forms a bronzy-blue paste which is dissolved with a chocolate colour by sulphuric acid, the blue colour being reproduced on the addition of water. It is slowly decolorised by zinc dust and ammonia, but is reoxidised on exposure to the air. On chrome-mordanted wool or cotton it yields pure blue shades. The fastness of these two dyes to soaping or milling is scarcely satisfactory, but they resist light fairly well. Chrome-green, obtained by condensing the above hydrol base with benzoic acid and oxidising, is faster to light than the basic green dyes, and is recommended for shading cærulein and other dyestuffs fixable on the chromium mordant, in calico-printing. Chrome-yellow is supplied in the form of paste. It is very fast to light and soaping, and withstands a moderate treatment with bleaching powder solution, and can be used in calico printing as a substitute for Persian berries and other phenolic yellow colouring matters. All the above "chrome" colours are printed on calico with acetate of chrome, and are steamed and soaped as usual. DIPHENYLMETHANE DERIVATIVES. The so-called Acridine reds, 3 B, 2 B, and B, are scarlets. 3 R, 2 R, and R, are diphenylmethane compounds. They are suitable for dyeing silk, wool, or cotton, mordanted with tannic acid, and for printing cotton in conjunction with the same mordant. They are bright but not very fast. Acridine orange, obtained by molecular transformation of tetramethyltetramidodiphenylmethane (Eng. Pat. 8243 of 1890; this Journal, 1891, 537) is an acridine derivative. MISCELLANEOUS COMPOUNDS. Capri blues GON, GN, and VN, are produced by the action of nitrosamines on the compounds which result from treating dimethyl-m-amidocresol with dichlorimidoquinone. Sulphuric acid dissolves them with a green colour which becomes red and then blue on the addition of water. They are fixed on cotton by the tannic acid mordant and are tolerably fast to soap. They can also be used for dyeing silk, wool, jute and leather, but have the drawback of possessing comparatively little colouring power. Fast Neutral-violet B is a basic dye, formed by the action of nitrosodimethylaniline on diethyl-m-phenylenediamine. It may serve as a substitute for Methyl violet which it somewhat surpasses in fastness to light. It is applied in the same way as the latter, 6 per cent. of the commercial 40 per cent. paste giving deep shades. Sulphuric acid dissolves it with a brown colour. Metaphenylene blue 2 B is prepared from nitrosodimethylaniline and di-o-tolyl-m-phenylenediamine (Eng. Pat. 5852, 1888; this Journal, 1889, 281) and is a valuable dye for cotton. The colours it gives on the tannic acid mordant may serve in many cases as substitutes for indigo, so fast are they to light and soap. The 2 B dye is faster to light than the dyes distinguished by the shade-marks R and B, and is superior in this respect to Indoïne, New blue, and the indazine blues. For printing, these dyes are of little importance. New Methylene blue has the constitution It gives pure blue shades like those of Toluidine blue (this Journal, 1892, 31). For calico printing it possesses the advantage, as compared with Methylene blue, of combining less readily with the tannic acid of the printing-mixture before printing. Its fastness is similar to that of Methylene blue 2 B. It dissolves in concentrated sulphuric acid with a greener colour than the latter dye. Hypochlorites render its aqueous solution brown-red, whereas they do not affect Methylene blue. Chromines G and R are obtained by heating dehydrothiotoluidine with sulphur and sulphonating the product, the more-highly sulphonated compound having the redder shade. Chromine G closely resembles Thioflavine S. It forms a brown-yellow powder which dissolves readily in water, and colours sulphuric acid a brown yellow. Cotton is best dyed with it in a bath containing sodium phosphate, although good results are obtained with common salt, sodium sulphate and borax, a pure yellow being produced which is very fast to soap but only slightly so to light. With silk, borax forms the best addition to the dyebath, sodium acetate yielding a greenish yellow. As this dye withstands the actions of chlorine and stannous chloride it may be useful in calico printing for the production of discharge effects. Arindone blues R and G are soluble dyes, prepared by the action of p-phenylenediamine on insoluble indulines. Cotton is dyed with them, either after mordanting with tannic acid, in which case 1 to 3 per cent. of alum is added to the dyebath, or directly in a bath containing sodium acetate and acetic acid. The first method yields a moderately bright-blue which may be darkened by passing through a dilute boiling solution of potassium bichromate. The second method yields shades which may be rendered greener and brighter by soaping. The shades obtained are very fast.-E. B. A Method of Discharge-Printing on Indigo. Sealed note No. 407 dated November 14, 1884. Storck and Pfeiffer. Bull. Soc. Ind. Mulhouse, 1892, 387–390. A THICKENED Solution of aluminium chlorate when printed on indigo-dyed calico and passed through the steam-ageing apparatus, effects a slight discharge of the blue. This action is increased by adding a small quantity of vanadium chloride to the printing-mixture, as it is also by steaming under pressure for a short time. A mixture of aluminium chlorate and a certain proportion of a sulphocyanide, more especially the ammonium salt, has the power of oxidising indigo even at the ordinary temperature, but this mixture is very difficult to thicken suitably for printing. The difficulty may be avoided, however, by preparing the cloth with the sulphocyanide, and printing a thickened solution of the chlorate, a very effective discharge being produced, and alumina deposited on the fibre which may subsequently be dyed. Ammonium chlorate, again, when steamed, destroys indigo, thus rendering it possible to obtain white patterns simultaneously with colour-effects on the alumina mordant. But all these processes have the serious drawback of impairing the tenacity of the fibre. The authors accordingly turned their attention to aluminium bromate, which they found when dissociated did not injure the cotton fibre to the same extent as did the chlorate of the same base, and were thus led to devise an economical method of manufacturing barium bromate, from which the aluminium salt is most conveniently prepared. This method consists in converting the whole of the bromine in combination with calcium, as obtained by boiling the product of the action of bromine on calcium hydrate, into calcium bromate, and then decomposing the latter by interaction with barium chloride as indicated in the equations: 1. Ca(BrO3)2 + 5 CaBr2 + 30 CaOCl, 2. 6 Ca(BrO3)2 + 30 CaCl2 + 6 BaCl, = the barium bromate, owing to its sparing solubility being readily isolated. In order to obtain aluminium bromate from it, it is necessary to heat the mixture of it and aluminium sulphate solution almost to boiling, as the decomposition is exceedingly slow at the ordinary temperature. A concentrated solution of the aluminium salt may be obtained without difficulty, and merely requires mixing with starch paste to prepare the printing-mixture. Additions to the latter of vanadium chloride and of sulphoeyanides are of no advantage, but additions of alkaline or alkaline-earth chlorides produce a marked improvement in the results. The discharge is effected by steaming, and the alumina which simultaneously becomes fixed is afterwards dyed with alizarin, &c. The process has been tried on the large scale with entirely satisfactory results (see also this Journal, 1892, 812 and 813). The Change of Shade during Steaming of Printed AzoColours on Wool. F. Binder. Bull. Soc. Ind. Mulhouse, 1892, 382-386. THE change of colour of azo-dyes printed on woollen tissues which sometimes takes place during the steaming operation, is due to the action of sulphurous acid which has been absorbed by the fibre in the process of bleaching, and which has escaped oxidation in the subsequent chlorination of the material. To remove the whole of this acid it is necessary to carry on the chlorination to an excessive degree, thus causing the wool to take an objectionable permanent yellow hue, which is intensified by steaming. Hydrogen dioxide readily oxidises the acid without injuring the wool, but is too expensive for use for this purpose. The dyes under the influence of sulphurous acid become transformed into bisulphite compounds of the typeH.N:N.SO,Na which, when fixed on wool, resist the ordinary operations of steaming and washing, The author finds that such compounds may, as a general rule, be readily decomposed by re-steaming the printed tissues for a few minutes between folds of cloth moistened with an ammoniacal solution of sodium chlorate, the primitive shades of the dyes being thus restored. Certain dis- and tris-azo dyes, however, behave exceptionally, Naphthol black, for example, which is changed to a dull puce by sulphurous acid, not being so restored. In applying the latter class of dyes the addition of an alkaline chlorate to the printing mixture is sometimes made. This protects the dyes in large surfaces of colour, but is ineffective with small patterns, which are changed in colour by the sulphur dioxide evolved in the steaming from the unprinted parts of the cloth. A better plan with such dyes is to employ steaming cloths moistened with an ammoniacal solution of sodium chlorate, the change being then prevented from taking place. The cloths can be employed several times, being moistened with dilute ammonia before re-use. A passage through dilute ammonia solution or hypochlorous acid will also restore the altered shades of monazo dyes. but the above method is more practicable.-E. B. Employment of some Induline Dyestuffs. G. Ulrich. Mitt. k.k. Techn. Gewerbe-Museums, 1892, 292-295. THE induline sulphonic acids of the benzene series have been but little employed in wool dyeing owing to a lack of fastness, and the irregularity with which the colour is deposited. Loose wool may be dyed, however, by placing it in 20 parts by weight of a cold bath containing 2-4 grms. of the colour and 0.5 grm. of ammonium oxalate per litre, and boiling for 2-3 hours; the material is then withdrawn, washed, and placed in a solution of sodium sulphate and sulphuric acid or tartar preparation. Worsted gives good results when steeped for 1-2 hours in a boiling bath containing 50-80 per cent. of ammonium oxalate and 3 per cent. by weight of the yarn of Wool Induline B; after washing and drying, the deep blue colour shows no irregularities, and is unaffected by rubbing or light. The colour withstands fulling if the operation be carefully performed, and the yarn dried as soon as possible. The rosindulines may be applied to wool in the same manner as the preceding. Naphthyl blue gives a very pure violet blue, and Naphthyl violet a very full reddish violet; the colours are stable towards fulling and light. The sparing solubility of the rosinduline dyes, which has proved a hindrance to their application to wool printing, may be avoided by adding ammonia to the printing colour in place of sulphuric or tartaric acid. After 1 hour steaming, the print resists washing. Medium deep shades only can be obtained in this way, but by the addition of tannin to the usual acid rosinduline printing colour, the dyestuff is either held in solution or is in so fine a state of division as to work satisfactorily. The application of a printing colour composed of 20 grms. of Rosinduline G, 20 grms. of tartaric acid, 100 grms. of tin salts, and 600 grms. of starch-tragacanth thickener per 1,000 grms., to woollen fabrics dyed with sulphone-azurine, and steaming forone hour, completely discharges the latter colour and gives very good results. Rosinduline 2 G requires the addition of oneeighth part of tannin, for printing, a quarter part should be used; the fixation is incomplete without further addition of acid. Tartaric acid gives bluer shades than sulphuric acid; half a part of tannin should be added to the dye in preparing discharge-printing colours. Rosinduline B and G require half a part of tannin. Rosinduline 2 B requires a quarter part, and the blue shade one-third part of tannin; the latter colour loses in intensity on washing, if not steamed for an hour. Excess of tannin should be avoided, and sulphuric acid is the most suitable to use.- -W. J. P. Preservative against the Discharge of Indigo by Potassium Bichromate. A. Kertész. Mitt. k.k. Techn. GewerbeMuseums, 1892, 298-299. As a preservative against the discharge of indigo in printing fabrics with a discharge colour containing potassium bichromate the author recommends the following mixture : -2 litres soda ley (24° B.); 1 litre sodium bisulphite solution (35° B.); 2 litres of water, 3 litres of gum tragacanth solution, 2 kilos. of dextrin, and 2 litres of potassium thiocyanate solution (35° B.).-W. J. P. The Steaming of Printed Fabrics. E. Jaquet. Bull. Soc. Ind. Mulhouse, April-May 1892, 288. THE author has studied the "marking off" during steaming of printing colours and the means of avoiding such damage. This may arise in some cases from the hygroscopic character of the colour, the "marking off" being due to simple contact; but in the more frequent and important instances it is caused by a sublimation of the colouring matter and its transportation by the vapour to the unprinted parts of the cloth. Colours made from alizarin are subject in particular to such marking off, and these have been specially studied. An alizarin-red printed on a non-oiled │ calico marks off much less than one on oiled cloth; an alizarin red, or claret, or purple marks off the more readily the more acid the mordant is, particularly if the acid is a strong one, as in the case of a sulphate of alumina or of chrome incompletely converted into acetate. It may, therefore, be concluded that the tendency to mark off diminishes in proportion to the rapidity with which the colour-lake is produced. As, however, a too rapid reaction in many cases injures the solidity of the resulting colour, it is not always advisable to use a neutral mordant. To determine the cause of the marking off of an alizarin-red colour, a fent printed with an alizarin-red blotch was steamed in contact with calico prepared in the following ways and subsequently soaped. With white unoiled cloth the marking off was nil: with oiled cloth it was scarcely perceptible; with cloth prepared in alumina it was exceedingly strong. A second trial was then made with the same white cloths, but first printing them with an alizarin-red colour, using an open sprig pattern so as to leave as much white as possible. On steaming these in contact with the alizarin blotch, the whole of the fents showed strong marking off, the aluminaprepared cloth being worse than the others. It is evident from this that the alumina is the cause of the marking off, this fixing the alizarin that is sublimed from the printing colour; and in the case of the fents printed with the open pattern the smooth part of the roller has furnished sufficient alumina to fix the alizarin. This conclusion was confirmed by printing on unoiled cloth an alizarin-red colour in the one case by roller and in the other by block, and then steaming as in the previous trials. The former showed distinct marking off, the latter hardly a trace. The remedy for such marking off is therefore to be found in preparing the tissue with a resist which shall prevent the fixation upon it of alumina, and this is best effected by adding a little citric acid to the alizarin oil used in preparing the cloth. Such an addition has been used in certain Mulhouse works for many years with excellent results.-W. E. K. Note on the Turkey-Red Oils of MM. Schmitz and Toenges. P. Werner. Bull. Soc. Ind. Mulhouse, April -May 1892, 291. THESE are a new class of Turkey-red oils patented and sold by Schmitz and Toenges, of Heerdt, near Düsseldorf, and placed on the market under the name of "oxyoleates." In their preparation, the usual course of treatment of the oil with sulphuric acid is followed, but the salted-out fat is subsequently heated in open vessels to from 105° to 120° C. In this operation the whole of the sulphur is eliminated as sulphurous and sulphuric acids, and a new product is obtained, considered by the inventors to be an "oxyoleic" acid. The author has examined a number of these products, and finds that they possess in certain cases advantages over the usual Turkey-red oils, whilst at the same time they are not higher in price.-W. E. K. Improvements in Dyeing Vats. A. Dreze, Liège, Belgium. Eng. Pat. 148, January 4, 1892. A CENTRAL pipe in the form of an inverted truncated cone is fixed to a perforated false bottom in the vat. In the annular space between this pipe and the sides of the vat the goods are placed. An upper perforated plate is placed above the goods. Steam is introduced by means of a pipe having its orifice below the truncated cone. This acts as an injector, and a rapid circulation of the dye-liquor (upwards through the cone, and downwards through the material contained in the annular space around the cone) is effected.-W. E. K. Improvements in Bleaching. H. Thies, Laaken, Germany, and E. Herzig, Mulhouse, Alsace. Eng. Pat. 4278, March 4, 1892. THIS invention relates to a preparatory treatment of fibrous materials in bleaching (prior to scalding the same) for the purpose of expelling the air from the fibres. The process consists in subjecting to pressure the materials to be bleached contained in a scalding-vessel filled with alkaline liquid, which thereby absorbs the air adhering to the fibres, and driving thereafter the alkaline liquid into an accessory reservoir where it is freed from the absorbed air by reducing the pressure. These two operations are carried out in a continuous manner, the alkaline liquor circulating through the two vessels. In order to complete the removal of air from the fibres a sulphite is added to the alkaline liquor. After this preparatory treatment the goods are bleached by means of the circulation of caustic soda lye through the vessels. It is claimed that by the preparatory treatment the fibrous materials are protected from shrinkage and oxidation and a better and quicker bleach effected. -W. E. K. An Improved Process for the Production and Fixation of Colours in Conjunction with Aniline Black upon Woven Fabrics. F. F. Grafton, Manchester, and W. Browning, Accrington. Eng. Pat. 11,416, June 18, 1892. (Second Edition.) THE specification describes a method for the production of coloured designs on a background of aniline black on calicoes and other woven fabrics by means of the following operations: The cloth is first impregnated with tannic acid or tartar emetic or other suitable mordant and is then padded with aniline oil and other materials for the production of aniline black by ordinary methods. After drying, the design is printed with Methylene blue or other colouring matter which is mixed with sodium acetate and a gum to act as a "resist." The aniline black is then developed by steaming or ageing, when only those parts not protected by the design will develope, whilst at the same time the printed colouring matter will become fixed and prevent the formation of aniline black upon those parts of the fabric which have been printed.-T. A. L. VII.-ACIDS, ALKALIS, AND SALTS. The Action of Aluminium on Mercury Salts. J. Klaudy. Mitt. k.k. Techn. Gewerbe-Museums, 1892, 217-222. THE interaction of aluminium and mercury salts cannot be properly investigated with aqueous solutions of the latter, as the amalgam which is first formed decomposes water and secondary changes occur. The action of aluminium on a saturated alcoholic solution of mercuric chloride was, therefore, studied. A thin sheet of aluminium, on being immersed in such a solution, quickly becomes covered with a film of mercury, and thereupon commences to dissolve. The action then proceeds at an accelerated rate, with the evolution of so much heat that the alcohol is caused to boil vigorously. After a time the action slackens, and a small quantity of gas, presumably hydrogen, is evolved. Finally, towards the end of the reaction, if an excess of aluminium has been used, a separation of basic aluminium chloride, containing Al and Cl in the ratio 1:1, takes place. If, however, the mercuric salt and aluminium are taken in the proportion of Al: 3 HgCl, the aluminium dissolves completely, and the solution on evaporation leaves a residue of aluminium chloride. When a still larger proportion of mercuric chloride is used, the mercury which separates becomes acted upon and mercurous chloride is formed. Only when the amount of aluminium greatly exceeds the above proportion, does the action cease at the formation of the amalgam. The quantity of mercury which is required to produce the latter body is exceedingly minute, the amount deposited in an experiment in which the amalgam was weighed under alcohol and then immersed in water to oxidise the aluminium in it, being found to be 0.0353 grm. in 2.8567 grms. of the amalgam, of which 1.5834 grms. were unaffected by the water. This gives the ratio of Hg: "active" Al as 1:267, and proves that the metals do not chemically combine, but merely form a galvanic couple. Other mercury salts than mercuric chloride can be used to prepare the amalgam, but the latter salt acts best. Amalgamated aluminium has an intense affinity for oxygen. Exposed to the air it is slowly oxidised, whilst so Imuch heat is evolved that the mass becomes heated to 80°. It also readily decomposes water and steam, liberating hydrogen, and reduces potassium permanganate and bichromate, and alkaline potassium ferricyanide, as well as organic oxygen compounds, such as nitrobenzene, indigo, &c. It displaces from solutions of their salts all the metals which are precipitable by zinc, and in addition to the latter metal, iron, manganese, &c. Acids and potassium and sodium hydrates easily dissolve it. Hydrocarbons and absolute alcohol are without action upon it.-E. B. The Water of Crystallisation of Barium Thiocyanate (Sulphocyanide). J. Tcherniac. Ber. 1892, 25, 2627— 2629. BARIUM THIOCYANATE contains 3 and not 2 mols. of water of crystallisation, as has been previously thought, and has therefore the formula Ba(SCN)2 3 H2O. The salt also forms alcholates with methyl and with ethyl alcohol, which contain 2 mols. of alcohol of crystallisation. The methyl alcohol compound Ba(SCN),, 2 CH3.OH forms glittering prismatic needles, as does the ethyl compound; the latter effloresces readily.-C. A. K. The Partial Substitution of Sodium Cyanide by Potassium Cyanide in Commercial Cyanides. T. B. Stillman. Jour. Anal, and Applied Chem. 6, 1892, 467-469. THE author has discovered that a mixture of sodium and potassium cyanide is cheaper, and for many purposes superior to the 98 per cent. potassium cyanide, since it contains a higher percentage of cyanogen. The mixture can be made at a less cost than the potassium cyanide alone, as may be seen from the formula for its manufacture2 K4Fe(CN)6 8 KCN + 2 FeC2 + N4 2 Na,Fe(CN)6 = 8 NaCN+ 2 FeC2+ N The method adopted by the author to determine the proportions of potassium and sodium was as follows: The cyanides were converted into sulphates by evaporating their solution in water in presence of an excess of sulphuric acid. After ignition and weighing the sulphates, they were dissolved in water, and the sulphuric acid was determined in the ordinary way by precipitation with barium chloride. From these data were calculated the percentages of potassium and sodium respectively in the cyanide. To these results is added the percentage of cyanogen, as determined by titration with semi-normal silver solution. A commercial sample of " 98 per cent." potassium cyanide gave the following result: New Process for the Manufacture of Potash. D. Sidersky. Le Génie Civil, 21, 1892, 410; Proc. Inst. Civil Eng. 1892-3, 111, (1) 116. THE production of potash from the Stassfurt salts, which consist of variable compounds of sulphates and chlorides of potassium, sodium, and magnesium, has hitherto been effected by the Leblanc process, a method which is not only expensive, but gives a large amount of waste products, whilst the finished article is not easily obtained in a pure state; so that these minerals are almost entirely sold for agricultural purposes. In the new method described by the author, and patented by the Buckau Chemical Company, the whole of the constituents are utilised with the production of potash, soda, calcined magnesia, crystalline sulphate of lime, hydrochloric acid, and sulphuric acid. The material best suited for the process is the mineral kainite, the average composition of which is— This is first converted into sulphates by treatment with sulphuric acid, the hydrochloric acid being condensed, as in the Leblanc process. The magnesium sulphate is next decomposed by the addition of lime, which produces calcium sulphate and magnesia, both of which are insoluble. This operation is effected by adding the necessary quantity of concentrated milk of lime to the boiling solution of kainite sulphates of a density of about 20° B. At first the lime dissolves in the hot solution; but when left at rest for some days after slow cooling, the calcium sulphate separates as a heavy crystalline powder covered with a lighter deposit of magnesia. These, after removal of the saline solution, are washed and separated by decantation, and finally collected in the filter-press. The solution of potassium and sodium sulphates is next treated with barium sulphide, giving insoluble barium sulphate and solutions of the alkaline sulphides, which after filtration, are boiled down to a strength of 20 B. and subjected to the action of pure concentrated carbonic acid gas obtained from the decomposition of alkaline bicarbonates. This decomposes the sulphides, producing sulphuretted hydrogen, which is burned and converted into sulphuric acid and bicarbonates of sodium and potassium. The former salt, being almost insoluble in the cold solution, is separated by filtration, and the potassium salt is obtained by boiling down the filtered liquid. Lastly, the bicarbonates are transformed by calcination into neutral carbonates, the carbonic acid gas driven off being employed in the decomposition of the alkaline sulphides. This is said to be the first industrial application of pure carbonic acid, and to be essential to the success of the operation, which cannot be carried out with limekiln gases, on account of the presence of free oxygen in the latter, whereby a certain proportion of the sulphides are invariably changed into sulphates. The order of operations given above may be varied by separating the magnesia with lime before the conversion into sulphates. The mixed sulphates may also be converted into sulphides by calcination with coal, which completely decomposes the magnesian sulphate, and converts the alkaline sulphates into sulphides. The product when lixiviated in Shank's apparatus, gives a precipitate of magnesia and alkaline sulphide liquors for the carbonic acid treatment. The conversion of potassium and sodium sulphates into sulphides by carbon alone has not been found to be practicable, owing to their ready fusibility and corrosive action upon the furnace-bottom when melted. The presence of magnesium sulphate, however, alters the conditions, as the mass becomes fritted with an infusible substance, caustic magnesia, and the conversion takes place at a temperature below that necessary to develop the corrosive action of the material. PATENTS. Improvements in the Manufacture of Caustic Alkalis. J. E. Bott, Stockport. Eng. Pat. 18,482, October 27, 1891. THE invention relates to the concentration or evaporation of caustic lye. It consists in principle of blowing heated air through the lye contained in a vessel hung on trunnions. The bottom of the vessel is perforated to allow of the passage of tuyers through which the hot air is forced through the lye contained in the vessel, the air and watervapour passing away from the upper part of the vessel above the suface of the lye. In the apparatus, drawings of which accompany the specification, the trunnions are hollow, the hot air being led to the apparatus by one trunnion and the air and vapour being passed away by the other. When the lye is sufficiently concentrated or dried, the vessel is tipped over, the air-blast cut off, and the contents of the vessel removed through a suitable aperture in the top. Instead of air, carbonic acid may be blown into the lye when desired.-H. S. P. Improvements in the Preparation of Acetate of Ammonia for Use in the Manufacture of White Lead by the Acetate of Ammonia Process. W. Smith, London. Eng. Pat. 18,693, October 29, 1891. THE object of this invention is the economical production of pure ammonium acetate, suitable for the preparation of white-lead (this Journal, 1892, 45 and 360). This end is obtained by a series of operations (1) for the production of pure calcium acetate from the commercial crude acetate of lime; (2) for the conversion of the same into ammonium acetate. Crude grey acetate of lime is dissolved in a little water, settled, and the strong solution treated with an excess of strong sodium sulphate solution for conversion into sodium acetate; part of the pyroligneous matter is hereby carried down with the simultaneously-formed gypsum. The solution is now concentrated, and the crystallised sodium acetate so obtained distilled with sulphuric acid of 140° Tw. ; the remainder of the tarry matters is thus destroyed and sufficiently pure acetic acid distils over. This is now neutralised with lime, boiled down, the calcium acetate salted out and redissolved in water. The decomposition with ammonium sulphate proceeds best at 60-80° C., and the resulting ammonium acetate solution may be used for the treatment of litharge. The residue from distilling with sulphuric acid may be dissolved, filtered, and boiled down for the recovery of sodium sulphate.-H. A. Improvements in Distilling Apparatus suitable for the Treatment of Ammoniacal Liquors. A. Feldman, Bremen, Germany. Eng. Pat. 18,959, November 3, 1891. THE apparatus consists of an inner cylindrical vessel for decomposing the ammonium compound with lime, and of an outer annular vessel for steaming off the volatile ammonia contained in the liquor both before and after treatment with lime. The annular vessel is provided with shelves; the liquor enters on the top, and passing by means of luted tubes over some of the shelves meets in its downward course a current of steam, which rises through luted bell-jars. The steamed liquor is discharged in the lime vessel, preferably by means of a tube reaching to the bottom of the same. The well-agitated mixture overflows on to another series of shelves, where the last traces of ammonia are liberated. The gaseous ammonia is taken off from the top of the annular vessel, and the spent liquor from the bottom of the same.-H. A. Improvements in and relating to the Manufacture of Chlorine. C. Hoepfner, Giessen, Germany. Eng. Pat. 19,375, November 9, 1891. THIS is an electrolytic process. Instead of electrolysing common salt, the inventor obtains chlorine by electrolysing |