0·02 — 0·04 grm. per 24 hours, showed a death rate of Homo-pterocarpin and Pterocarpin from Red Sandal THE physical properties of these two substances extracted Homo-pterocarpin, when heated until it decomposes, CH2 CH3 On Saccharine. Bruylants. J. Pharm. Chim. 1888, 292. Ir is usually supposed that saccharine is completely elimi. nated with the urine. The author took doses of 0.5, 1, 150, and 2 grms. respectively of saccharine, and on examining the urine of 24 hours could only account for 80 per cent., 82 per cent., 84 per cent., and 88 per cent. of the saccharine taken. A ewe received on different days, doses of 1, 2, and 5 grms. of saccharine without suffering in health. The milk at first contained none, the second time traces, and the last time large amounts of saccharine. Saccharine is often considered an energetic antiseptic, and recommended as an addition to beer. The author finds that 1 per cent. of it does not prevent the alcoholic fermentation, although the process is protracted, whereas an addition of 0.013 per cent. is without any action whatever; 2.5 parts of saccharine per mille cannot prevent the acetification of beer. The pepsin digestion is not disturbed by saccharine, whereas the fermentation of pancreatic fluids, which contain 1 per cent. of it, proceeds very slowly. The author also confirms the fact that taken as a medicine it is harmless. For some considerable time he took daily doses of the least injurious effect; it did not even interfere with the grms. without digestion. (Compare this Journal 1888, 688.)-S. H. The Relations between Atropine and Hyoscyamine. A. Ladenburg. Ber. 21, 3065-3070. WILL (this Journal, 1888, 584) found that hyoscyamine is converted into atropine when treated with dilute alkalis or when heated above its melting point. Will and Bredig, who investigated this subject more fully, came to the conclusion that atropine is an optically active base (a = -1.89). The author prepared atropine aurochloride from a sample of the purest commercial atropine (which was further purified by several recrystallisations), and recrystallised it 14 times; the resulting salt melted at about 140°, and an 18 per cent. solution of the atropine obtained from this salt was optically inactive. When an 8 per cent. alcoholic solution of commercial atropine is mixed with a few drops of very dilute soda, and kept for two hours, the solution is still optically active, but if the base obtained from the solution be recrystallised several times, its rotatory power decreases. When a 6 per cent. alcoholic solution of atropine is mixed with a small quantity of soda, and kept for 5 hours, the solution is optically active; after standing for 19 hours longer the solution is still optically active, but if the base be then twice recrystallised from dilute alcohol, the pure compound obtained has no rotatory power. From these results the author concludes that atropine is an optically inactive base, standing in the same relation to hyoscyamine as racemic acid to levotartaric acid, and that possible, has not yet been accomplished. He also found the conversion of hyoscyamine into atropine, although atropine, is recrystallised many times, small quantities of that when atropine aurochloride, prepared from ordinary the hyoscyamine salt are obtained, and he is also of the atropine results from the employment of impure materials. opinion that the supposed conversion of hyoscyamine into -F. S. K. Narcotine. W. Roser. Ann. 249, 156-172. A CONTINUATION of researches on the derivatives of narcotine. (This Journal, 1888, 518.) The present paper deals with those derivatives which have cotarnine for their starting point, and the author prefers Anderson's method, for the preparation of this substance from narcotine, by the action of nitric acid in preference to manganese dioxide and sulphuric acid. The melting point of cotarnine is given as 132-133°, at which it also begins to decompose. By the containing the two following substances:action of methyl iodide on cotarnine a product is obtained 13 Cotarnine hydriodide, C12HNO,HI, forms glittering yellow needles sparingly soluble in water and cold alcohol. Cotarnmethinmethyliodide, CH20NOI, is easily soluble in hot water, and crystallises by slow cooling in long glittering needles of light yellow colour. this with silver chloride the corresponding chloride, On digesting C14HNO4C1.3 H2O, is obtained, and is distinguished by its readiness to form large clear crystals. methyliodide is remarkable in being derived from cotarnine, Cotarnmethinnot merely by the addition of methyl iodide but by the inclusion of a second methyl-group. aqueous solution with caustic soda, a separation of oily On treating the drops ensues accompanied by the smell of a volatile base. The decomposition of the base of the salt is expressed by the equation The oily body forms on cooling a white crystalline compound, CHO4, which, having the characters of a ketone, is termed cotarnone. The volatile base is trimethylamine. From the nature of this change the constitutional formula of cotarnmethinmethyliodide must be (CHO)N(CH3)3I, and from a consideration of the transformation undergone by cotarnine in these reactions, the author draws the following conclusions : "The formula of cotarnine is not CHINO3. H2O, but C12HINO4, the so-called water of crystallisation belonging to the constitution. Cotarnine is a secondary base. "A pyridine group is not contained in free cotarn'ne, but is contained in its salts." Cotarnone, CH1004, is easily soluble in alcohol, ether or acetic acid, and crystallises from alcohol in rhombic plates, melting at 78°. It is an indifferent body, stable against alkalis, but transformed on warming with acids into dark-coloured products. Cotarnonorime, C10H1103(NOII), is formed on warming cotarnone with hydroxylamine hydrochloride in alcoholic solution. It crystallises from dilute alcohol in fine needles, melting and decomposing at 130°—132°. It Cotarnic acid, C ̧H¿O3(COOH)2, is obtained from cotarnone by the action of potassium permanganate. crystallises readily from water, and melts at 178°, with decomposition. It forms an acid potassium salt, which, on double decomposition with silver nitrate, yields a neutral silver salt and free acid. The author observes that hydrastinine comports itself on treatment with methyliodide in a manner strictly analogous to cotarnine, yielding a volatile base, and an indifferent substance as final products. The formula for cotarnine, and its relation to hydrocotarnine, as deduced from the results of these researches, may be thus expressed. XXII.-EXPLOSIVES, MATCHES, Etc. Improvements in the Explosives Industry. O. Guttmann. Dingl. Polyt. J. 270, 215–223. H. GÜTTLER (German Pat. 44,078, December 19, 1887) has patented further improvements in his charcoal furnace. The wood is introduced into the furnace in the form of pulp. The improved apparatus cannot be described in the absence of drawings; but it appears to be an important addition to this special branch of powder manufacturing. Le Boulenge's well known chronograph has been adapted to meet the requirements of the present high velocity of projectiles. The chief alteration consists in placing the wire frames that are shot through 100 metres apart, instead of, as formerly, 50; and in the same proportion the time recorded is increased. A special arrangement allows of the apparatus being used in places where the range is less than 100 metres. The French Explosives Commission has examined the conditions which give rise to the ignition of fire-damp by certain explosives. According to a report of Mallard and Le Chatelier (Revue Industrielle, 1888, 298), the heat generated by an explosion must exceed 2,200° before it will ignite fire-damp. Equal parts of dynamite and soda crystals, or sulphate of soda containing 10 aq., or ammonia alum, or ammonium chloride, when detonated in an atmosphere of fire-damp, failed to ignite it even in the presence of coal dust. Mixtures of nitro-glycerol and gun-cotton with nitrate of ammonium have a special advantage because the nitrate acts as an explosive, but depresses the temperature; the temperature of the explosion being, in the case of nitrate of ammonia 1,130°, that of dynamite, nitro-glycerol, and guncotton, being 2,940°, 3,170°, 2,636°, respectively. The Commission found that 20 parts of dynamite or nitroglycerol with 80 parts or more of nitrate of ammonium failed to ignite the most inflammable fire-damp. A. Zettler has introduced a new electro-magnetic exploder. According to experiments by Prof. Carl, it is capable of exploding 80 detonators at one time and weighs only 14 lbs. A new method for determining the percentage of glycerol in the crude material is suggested by R. Benedikt and M. Cantor. It is based on the observation that glycerol is converted into triacetin on boiling with anhydrous acetic acid. The triacetin is determined by dissolving in water, neutralising with soda solution and titrating back the excess. The increased demand for quality and purity of explosives has brought about a change in the methods of manufacture of the same, and on sounder and more scientific principles. Greater attention has of late been directed to electrical phenomena so often observed during the process of manufacturing gunpowder, but concerning which no safe conclusions have been arrived at owing to the absence of the evidence of reliable observers. The most important and also the most common occur rence is the accumulation or attraction of atmospheric electricity during storms. The buildings of explosive works, as a rule, are detached, and often in elevated positions. In England it is prescribed that the lightning conductor should be fixed on to the building itself. In other countries it is considered sufficient to attach the lightning conductor to a high staff near to the building, and we are of opinion that the buildings in question are afforded more protection. In many cases the lightning conductor has been known to favour the discharge of electricity, and it is suggested that an explosion of a powder magazine at Salonica occurred in this way. As regards the machinery in the buildings, precautions should be observed against the accumulation of atmospheric electricity as well as from other sources, more especially in the manufacture of explosives, of which sulphur is a constituent. In the powder works of W. Güttler the sulphur mills are connected with the earth so as to carry off the electricity, and since this arrangement has been introduced the sulphur has never fired, it being, previously, a matter of constant occurrence. storm. In another large powder works in Germany, not long since, an explosion occurred in the press-house after a The powder was between ebonite plates, and under pressure before the commencement of the storm. When the storm had ceased, a workman released the pressure and proceeded to separate the cakes from each other. According to a statement made by him before his death, a spark 10 centimetres in length was discharged into his finger as he was in the act of lifting one of the cakes. W. T. Reid has observed that warm air passing over nitro-cellulose generates electricity in considerable quantities. The generation of electricity has been observed in other industries during manufacturing processes, and several instances are quoted; but, according to the author, no instance has come to his knowledge which is of importance or which has caused immediate danger. The author considers that the extensive application of rubber, ebonite, &c. to machinery used for the manufacture of explosives is somewhat hazardous. In England, for instance, the shoots of the separators and the bed-plates of the granulating mills are lined with rubber composition. This stuff has the advantage that it wears well, and possesses certain elasticity combined with great strength, &c., but under favourable conditions such a bed-plate might act as an electrophorus. The author considers the question of the accumulation and attraction of electricity one which should receive greater attention, and observes that it should be made compulsory to connect all machinery and apparatus with the earth by conductors properly constructed.-C. N. H. PATENTS. Improvements in Explosive Compounds. H. E. Newton, London. From A. Nobel, Paris, France. Eng. Pat. 4172, December 2, 1875. (Third Edition.) 6d. THE object of this invention is to convert at the ordinary temperature, liquid explosive substances, such as nitroglycerol, the nitrates of methyl, ethyl and amyl, and nitrobenzene into a viscid or pasty state by incorporating these with another substance capable of gelatinising or thickening them, such substances being chosen which detract little or nothing from their explosive force, such as, for instance, gun-cotton. "Nitroglycerin may be gelatinised by dissolving in it nitrated cellulose, known as collodion cotton." About 7 per cent. of gun-cotton is found to be sufficient to form a solid jelly, "which is very safe and highly suitable for every purpose to which very powerful explosives can be applied." The addition of nitrobenzene, dinitrobenzene, charcoal, or ordinary gunpowder to gelatinised nitroglycerol is proposed, with a view of modifying the rapidity of combustion, and also of lowering the freezing point of the nitroglycerol.-C. N. H. Improvements in the Manufacture of Charcoal, O. Bowen, A. S. Tomkins, and J. Cobeldick, London. Eng. Pat. 11,537, August 24, 1887. 4d. THE object of this invention is to produce a charcoal rich in hydrogen, and suitable for the manufacture of gunpowder. For this purpose wood or suitable carbonaceous matter is subjected to a heated current of air mixed with hydrogen. The furnace employed has been described in Eng. Pats. 509 of 1831 and 1457 of 1886.-C. N. H. Improvements in Machines for the Compression of Gunpowder, and for similar Purposes. A. Greenwood, Leeds. Eng. Pat. 1153, January 25, 1888. 11d. THE object of this invention is to provide for the manufac ture of small cylindrical or conical pellets, for use in rifle cartridges, or of prismatic or cubical powder. The machine works automatically and is designed to perform the following operations :- To measure the quantity of powder required for each pellet; to place this powder in a mould; to insert one or more needles into the mould and apply vertical and lateral pressure, finally withdrawing the needles, and after removal of the pressure ejecting the finished pellet. For details the specification and drawings must be consulted.--C. N. H. Improvements in Explosive Compounds. C. D. Abel, London. From H. Schöneweg, Dudweiler, Germany. Eng. Pat, 1591, February 2, 1888. 4d. AN explosive mixture consisting of 20 parts of dinitrobenzene, 80 parts of potassium nitrate, and a proportion of ammonium oxalate, varying between 5 per cent. and 12 per cent of the other two ingredients combined. The oxalate of ammonia is added with a view of produc ing a flameless explosive.-C. N. H. Improvements in the Manufacture of Explosives. E. Turpin, Colombes, France. Eng. Pat. 4310, March 20, 1988. 6d. THIS invention relates to an improved smokeless powder for firearms, which is prepared by dissolving gun-cotton more or less nitrated in any solvent most suited to the kind of gun-cotton employed, e,g., "nitrobenzene and other nitrobodies of the aromatic series, aniline, aldehydes, amidocompounds of various kinds, acetone, sulphuric, nitric, acetic, and other ethers." Also" ammonia in solution in sulphuric or other ether, acetone in solution in sulphuric or other ethers or mixtures of ethers are suitable for dissolving gun-cotton more or less nitrated." The resulting paste is spread upon plates or trays with raised edges and allowed to dry. When sufficiently dry the sheets are rolled out to the desired thickness, and subsequently cut crosswise by suitable machinery in order to form small cubes. The rapidity of combustion of the powder is retarded by the addition of camphor, nitrobenzene, nitrotoluene, paraffin, &c. By varying the proportions of the ingredients above-named, "powders may be obtained adapted to suit all requirements."--C. N. H. Improvements in the Method of Preparing High Explosives for Use and in the Charges of Cartridges made of such Explosives. J. W. Graydon, Washington, U.S.A. Eng. Pat. 6498A, May 1, 1888. 8d. THE object of this invention is to prevent exudation or other physical change in high explosives, "as, for instance, dynamite, melinite, and roburite." The invention is carried out by separating the mass of explosive into a number of small portions, and entirely enclosing each portion in a separate envelope so as to form explosive pellets which can be packed together in a suitable wrapper or case to make a cartridge, or to be used or handled loosely without any casing. The purpose of the invention can also be attained by loading the explosives into cartridges containing partitions which separate it into small portions. Drawings of cartridges are attached to the specification.-C. N. H. XXIII.-ANALYTICAL CHEMISTRY. A New Spirit Lamp for obtaining High Temperatures, a Substitute for the ordinary Gas Blow Pipe. R. Rosenlecher. Chem. Zeit. 12, 1622-1623. THE shape of the lamp is that of the common Berzelius lamp, but, instead of a single wick, there are two concentric circular wicks a and b (Fig. 1). The space between the two Fig. 1. wicks is formed by platinum foil into a channel c, for the admission of air under pressure, which channel is provided at the top with 10 small holes, bored aslant at an angle a1, so as to concentrate the heat on one point. The amount of air required is very small, and can be easily supplied by a hand or foot blower of medium size. If the crucible to be heated be introduced into a fire-clay furnace (Fig. 2), a Fig. 2. white heat is readily attained, and if the fire-gases which escape be not likely to reduce the contents of the crucible, the furnace may be covered with a lid d, whereby the gases escape in the direction indicated by the arrows. It will be found best to have the height of wick from 2 to 3 mm., and the height of the flame from 4 to 5 cm. The burner may also be used in connexion with the common Berzelius lamp by being screwed down into the alcohol receiver of the lamp.-S. H. An Apparatus for the Electrolytic Estimation of Metals. C. Levoir. Zeits. Anal. Chem. 28, 63. THE solution to be electrolysed is contained in a platinum dish supported on three metallic knobs, which serve to conduct the current from the positive pole of the battery. A smaller platinum dish is suspended inside the first dish by means of three platinum wires, the distance between the two basins being three centimetres. The three wires are attached to a stouter platinum wire, which dips into a mercury cup connected with the negative pole of the battery. The liquid to be electrolysed is thus situated between the parallel surfaces of the two dishes. During the passage of the current, the oxygen, liberated on the bottom of the upper dish, bubbles through the solution, and keeps it in constant circulation. Every portion of the solution is, therefore, brought into contact with the negative electrode, resulting in the rapid and complete deposition of the dissolved metal.-H. T. P. Estimation of Zinc in Presence of Manganese. G. Neumann. Zeits. Anal. Chem. 28, 57-58. THE author finds that Bragard's method for the separation of zinc from formic acid solution as sulphide in presence of iron and nickel, is also applicable to the estimation of zinc in presence of manganese. The ratio of zinc to manganese, in the mixtures analysed, varied between wide limits. The results obtained were very satisfactory. -H. T. P. Arsenic in Precipitated Calcium Phosphate and its Estimation. H. Fresenius. Zeits. Anal. Chem. 28, 64-67. IT is well-known that precipitated calcium phosphate has been used for some time with considerable success as an addition to cattle food. The arsenic generally contained in the hydrochloric acid employed in the manufacture of the phosphate, finds its way into the latter in the shape of calcium arsenite and arsenate, and if present in quantity might exert an injurious influence on the health of the cattle fed with the phosphate. For the estimation of the arsenic the author recommends the method and apparatus devised by R. Fresenius and E. Hintz. Ten grms. of substance are placed in a retort and covered with 100 cc. of HCl of 119 specific gravity. When the precipitate has mostly dissolved, 5 cc. of a cold saturated solution of ferrous chloride are added, and the whole nearly distilled to dryness. The arsenic is then estimated in the distillate as trisulphide in the usual manner. Twenty-five samples examined by this method.were found to contain percentages of arsenic (metal) varying from 0.028 to 0.17. The question as to the maximum quantity of arsenic permissible in phosphates used for feeding purposes, in the opinion of the author, can only be solved by a series of practical feeding trials made with phosphates containing gradually increasing percentages of arsenic.-H. T. P. IN estimating copper electrolytically, it is advantageous to acidify the solution with nitric acid; but when chlorides are present, considerable time is taken up in evaporating the solution with sulphuric acid. The author found that when an ammoniacal copper solution is electrolysed, the metal separates in a spongy condition, but that if 2 to 3 grms. of ammonia or potassium nitrate be added, and then about 10 cc. of ammonia for every 100 cc. of the solution containing 0.1-0.3 grm. of metal, the latter separates in excellent condition, even when the strength of current employed varies between considerable limits. The operation is at an end when the solution has become colourless.-F. S. K. Determination and Separation of Zinc. J. Riban. Bull. Soc. Chim. 50, 518-520. See this Journal, 1888, 771.-C. A. K. Separation of Cobalt and Nickel by the Nitrite Method. M. Baubigny. Compt. Rend. 107, 685-686. THE author points out that lead forms a triple nitrite with potassium and nickel, similar to those obtained with the alkaline earths. It is a yellow-orange coloured precipitate, which is only slightly soluble in water, even when acidulated by acetic acid. The exact composition of the compound has not yet been determined, but it is clear that the presence of lead, like that of the alkaline earths, must interfere with the separation of cobalt and nickel by the nitrite method.-C. A. K. Tin. L. Vignon. Compt. Rend. 107, 734–737. IF metallic zinc be employed to precipitate tin from a solution of stannous or stannic chloride, the precipitated metal possesses the ordinary properties of tin, provided the solution contains an excess of acid; but if there be no free acid in the solution, i.e., if it be pure stannous or stannic chloride, the deposited tin always contains some stannous oxide. The quantity of the oxide formed increases with the length of time during which the deposition has taken place. The presence of this stannous oxide (SnO), which in the samples of deposited tin examined varied from 22 per cent. to 33 per cent., renders the metal quite infusible, and causes it to burn away, when heated in the air, without melting. When heated to a red heat in a current of carbon dioxide the tin sublimes in the form of minute globules, whilst a greyish powder is also deposited consisting mainly of stannous oxide. The specific gravity of this partially oxidised metal was found to be 6.910 to 7.198 at 15°; examined under the microscope it appeared of a fine dendritic structure, differing in this from pure tin, which, when precipitated on zinc, consists of compact needleshaped crystals,-C. A. K. On the Analysis of Commercial Scheelite. K. Rusag Chem. Zeit. 12, 1316. AUSTRALIAN Scheelite, commercially known as the crude material from which tungsten and tungstates are manufactured, contains as impurities, quartz, calcium carbonate, silicates, sulphur ore, and arsenical ores. If metallic iron occurs, showing its presence by magnetic attraction, it may be supposed to owe its origin to instruments used in mining operations. It is a moot point whether, in testing the commercial product, it is preferable to commence with the decompo sition of the tungstate of lime by means of acids, or with breaking it up by fusion with carbonate of soda. If the latter process be adopted, the presence of silica in the fused product necessitates recourse to a variety of difficult operations, and the possible formation of silicate of tungsten may necessitate further roundabout processes. It is not possible to decompose the tungstate of calcium by means of solutions of alkaline carbonates and oxalates, nor did the author succeed by means of boiling nitric acid in rendering the whole of the tungstate accessible to the subsequent action of ammonia. A better result is obtained with concentrated sulphuric and hydrochloric acids, which both decompose it completely when heated for a sufficiently long time, the residue, exhausted by water and ammonia, generally proving free from tungstates when fused with soda. Hydrochloric acid is the more easily applied of the two. It does, it is true, dissolve a portion of the tungstate, but precipitates it again when diluted. But as it is necessary, even when employing hydrochloric acid, to submit the silicates which have been separated to further tests, the most practical method appears to be to first remove the silica as fluoride of silica, which may be done without loss of tungstate by a mixture of hydrochloric acid and hydrofluoric acid; while, on the other hand, by heating with fluoride of ammonia, the formation of volatile combinations of fluorine and tungsten (also observed by Marignac) could not be avoided. According to this method, from 2 to 3 grms. of finelypowdered scheelite are heated with hydrochloric and hydrofluoric acids until the silicic acid and the excess of hydrofluoric acid have entirely evaporated. The dry residue is again moistened with fuming hydrochloric acid, diluted after some time with an abundancy of hot water, heated to boiling point, and left to settle. The tungstic acid which has separated is washed without bringing it on the filter by decanting with hot dilute hydrochloric acid, dissolved in ammonia, and filtered after rendering it capable of filtration by heating and the addition of sal-ammoniac. The filtrate is evaporated to dryness in a large flat porcelain dish. The residue of tungstate of ammonia, if pure, would firmly adhere to the dish, but this is prevented if, during filtration or afterwards, sufficient sal-ammoniac has been added, and particularly if it has been heated until the point when decomposition sets in. The salt is now transferred to a large tared porcelain crucible, any residue which adheres to the dish being dissolved in ammonia, sublimed sal-ammoniac (free from ash) added, and evaporated as before. This is added to that in the crucible, and the operation repeated, if necessary, once or twice. The sal-ammoniac is driven off, and the tungstate of ammonia decomposed at a temperature far below the visible red heat, which is only brought to bright red at the end of the operation. The remaining tungstic acid is of a pure yellow colour, provided the use of platinum vessels for ignition be avoided. Although only very sparingly soluble in ammonia, fused with soda it dissolves in water without leaving a residue, and, when boiled with sal-ammoniac, does not precipitate flocks of silicic acid or alumina.-T. The Detection of Acetanilide. Zeits. Anal. Chem. 28, 103-104. suspended over the liquid; the bleaching-powder solution quickly assumes an amber-yellow colour, especially when viewed by transmitted light. By reflected light it has a violet tinge, and after long boiling, a distinct violet colour is produced. Aniline treated in a similar manner gives an immediate violet colouration, but no intermediate yellow tinge is produced. To detect acetanilide in urine, Vulpius gives the following:-The concentrated urine is boiled for a few minutes with HCl, cooled, extracted with ether, the ether evaporated, and the residue dissolved in water and mixed with a few cubic centimetres of an aqueous solution of phenol, and half its volume of a 1 per cent. solution of bleaching-powder. A brownish-red colouration is produced, which is changed to a beautiful blue by ammonia. Yvon heats acetanilide gently with mercurous nitrate, whereby a body is produced which dissolves with a green colour in alcohol. D. Cella and Arzeno heat a few centigrammes of the substance very gently with 2-3 drops of a solution of mercurous nitrate, and after solution has been effected, add 2-3 drops of strong sulphuric acid, when a blood-red colouration is produced. The last reaction is given by resorcinol, phenol, salicylic acid, tannic acid, gallic acid, and thymol, but not by benzoic acid. F. A. Flückiger rubs up two parts of acetanilide with one part of caustic potash, moistened with chloroform, transfers the mixture at once to a test-tube, and heats very gently. The mixture turns brown, and gives off the very characteristic smell of phenyl carbamine.-H. T. P. Detection of Cotton-Seed Oil in Lard. Bishop and L. Engé. J. Pharm. Chim. 1888, 348. AMERICAN lard frequently contains as much as 50-60 per cent. of foreign fats, such as olein, "oleomargarin," cottonseed oil, and cotton-seed stearin, while hard tallow is added to give the product the requisite consistency. The best means of detecting cotton-seed oil is by the use of Bechi's test, of Labiche's reaction with lead acetate and ammonia, and of the rise of temperature with sulphuric acid. These are executed by the authors as follows: (1.) Bechi's test :- 5 grms. of the clear melted fat are heated with 20 cc. of absolute alcohol and 3 cc. of an alcoholic solution of silver nitrate, containing 2 grms. in 250 cc., for 10 minutes on the water-bath, with continuous shaking. In the presence of cotton-seed oil a colouration appears, which may also be observed in the fat itself on solidifying, and-if the alcohol be decanted off and the cake of fat dissolved in ether or petroleum spirit-in its cold solution. (2.) Labiche's test:-25 cc. of a solution of lead acetate containing 500 grms. per litre (heated to about 35° C.) are mixed with 25 grms. of the clear melted fat, aud 5 cc. of ammonia (22° B. or sp. gr. 924) added with vigorous stirring for some minutes. The colour (orangered) is observed after 24 hours. (3.) Rise of temperature with sulphuric acid :—20 grms. of the clear fat are allowed to cool to about 30° C., the temperature exactly taken, and 20 grms. of sulphuric acid of a specific gravity not less than 1.836 run in, while the mixture is stirred vigorously with a thermometer; when the temperature ceases to rise, it is read off, and the genuine lard gave a rise of temperature of 35° C., with an total rise in temperature thus ascertained. Treated thus, acid of specific gravity of 1837 and of 42° C. with one of specific gravity 1842, while with the former acid a very old sample of cotton-seed oil gave 70° C., and a new one 66° C. In all three tests the age of the sample does not much affect their value, though with Bechi's test a greater reduc tion of silver nitrate takes place with a new than with an old oil, and with Labiche's reaction the colouration is more marked in the case of an old oil. The authors conclude that the detection of cotton-seed oil in lard is easy, but that no reliable method exists for its estimation. (For recent papers on the same subject, see the " Analyst," 13, 161, 165, 168, 170, 172, 189, 203.)—B. B. |