Estimation of Potassium by Reduction of the Platinochloride with Sodium Formate. By WouSSEN (Ann. Agronom., 13, 431—432).—The author has made Corenwinder's process workable by securing the agglutination of the reduced platinum. The modified process is conducted as follows:-So much of the substance should be taken as will yield 0.750 to 1 gram of reduced platinum from the potassium platinochloride. This is precipitated with 18 c.c. of a solution of platinum tetrachloride, containing 200 grams per litre, and a slight excess of nitric acid; 8 to 10 c.c. of hydrochloric acid is added, and the solution evaporated to dryness on the water-bath, then taken up with a mixture of nine-tenths alcohol of 96°, and one-tenth ether, filtered, and washed with the same mixture. The mixture of potassium platinochloride and salts remaining on the filter is treated with a jet of boiling water, and the hot solution of the platinochloride thus formed added in portions to a boiling solution of 2 to 2.5 grams of sodium formate in 10 c.c. of water. The boiling is continued for 15 to 20 minutes, and then 8 c.c. of hydrochloric acid is added, and the boiling continued with constant agitation. After this addition the reduced platinum soon agglutinates, and leaves the solution clear; the metal is collected, washed with boiling water, dried, and weighed. J. M. H. M.

Estimation of Potash in Commercial Manures. By D. LINDO (Chem. News, 56, 163-165).-Gladding has proposed the following method for this purpose :-Boil 10 grams of the manure for 10 minutes with 300 c.c. of water, when cool precipitate by means of a slight excess of ammonia, make up to 500 c.c., and filter. Evaporate 50 c.c. of the filtrate nearly to dryness, add 1 c.c. of dilute sulphuric acid (1 : 1), continue the evaporation to dryness, and ignite. Dissolve the residue in hot water and a few drops of hydrochloric acid, add 5 c.c. of a 2 per cent. solution of sodium chloride and an excess of platinum chloride solution and wash the precipitate successively with alcohol, solution of ammonium chloride (saturated with potassium platinochloride), and finally again with alcohol, dry, &c. The author has made numerous experiments with this method, and finds it simple, more expeditious, and seemingly susceptible of greater accuracy than the methods usually employed. D. A. L.

Estimation of Sodium Hydroxide in Soda-ash. By R. WILLIAMS (J. Soc. Chem. Ind., 6, 346).-The following method is found to give accurate results:-A weighed quantity of soda-ash is agitated with strong alcohol in a stoppered flask and left over night; the undissolved carbonate is filtered off and washed with strong alcohol until a drop gives no alkaline reaction; the filtrate and washings are then titrated with normal acid. D. B.

Estimation of the Relative Amounts of Sodium Hydroxide and Carbonate in Commercial Soda-ash. By P. HART (J. Soc. Chem. Ind., 6, 347).—The sample under examination is titrated with standard acid, using phenolphthalein as indicator. As soon as the colour disappears, the whole of the hydroxide and one half of the soda

existing as carbonate has been neutralised, the number of c.c. being noted. To the same solution (in which the soda now exists as sodium hydrogen carbonate) a little methyl-orange is added, and the addition of acid from the same burette continued to neutral reaction. By doubling the difference between the two titrations and deducting the number from the number of c.c. consumed, the quantity of hydroxide in the original sample is obtained. D. B.

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Analysis of Alum Cakes. By R. WILLIAMS (Chem. News, 56, 194-195). The author has adopted the following methods:-For alumina neutralise the solution with sodium carbonate, add a large excess of sodium hyposulphite, boil for some time, wash, dry, ignite, and weigh the precipitate. For free sulphuric acid: digest all night with strong alcohol, and titrate the alcoholic extract directly with decinormal soda, using phenolphthaleïn as indicator. Evaporating off the alcohol gives rise to loss, low results are likewise obtained if the digestion is not continued for a sufficient time. In another method, a weighed quantity of quinine, morphine, or strychnine is treated with a known quantity of alum solution, and the alkaloïd reweighed after the treatment, the loss representing the alkaloïd dissolved by the free acid. Comparative results were obtained as follows: :

The alkaloid results are all higher than the alcohol, probably on account of some alkaloïd being dissolved by the alum solution and reckoned as sulphate.

D. A. L.

Determination of Minute Quantities of Iron, with Special Reference to Alum and Aluminium Sulphate. By R. R. TATLOCK (J. Soc. Chem. Ind., 6, 276-279).-As a standard, a solution of iron-alum is used, of which 1 c.c. equals 0·001 gram iron. Place 1 gram of the finely powdered sample in an ordinary stoppered sample-tube of about 30 c.c. capacity, and having three marks at 7-5, 10, and 20 c.c. respectively. Add 1 c.c. of standard sulphuric acid, and make up to the lowest mark with water. When the alum under examination is dissolved, add 0·2 gram of ammonium thiocyanate and make up to 10 c.c. with water. Place 1 c.c. of the standard iron solution in a 100-c.c. flask, and make up to the latter volume with water. Now place 1 c.c. of this diluted solution in a stoppered sample-tube, add 1 c.c. of standard acid, make up to the lowest mark with water, add 02 gram of the thiocyanate, and make up to the 10 c.c. with water. Then fill up both tubes to the 20 c.c. mark with ether, and agitate them thoroughly. As soon as the contents settle, compare the tints, and if unequal make one or more further trials with greater or less quantities of standard iron solution until the two tints correspond.

D. B.

Detection and Estimation of Organic Substances. By J. H. SMITH (J. Soc. Chem. Ind., 6, 98-111 and 260-271).-When potassium permanganate is used as an oxidising agent in organic research,

impure products are obtained, and in varying proportions depending on the amount of reagent employed, temperature, and other conditions. It has therefore only been generally employed as a qualitative reagent. From a study of the behaviour of solutions of various organic substances in presence of a large excess of potassium permanganate under varying standard conditions, it occurred to the author that by employing an excess of the reagent, definite and simple compounds would be obtained whose composition in each case might be determined qualitatively by ordinary analysis, and quantitatively by an estimation of the oxygen absorbed in the reaction. The determinations which the author had in view were the following:-Oxygen yielded by excess of manganese dioxide in acid, alkaline and neutral solutions respectively; oxygen yielded by excess of permanganate in such solutions. The latter would include the former, the difference would represent oxygen yielded by permanganate in reduction to manganese dioxide only, and would necessarily correspond with more stable compounds than those represented by the reduction of manganese dioxide. The author further anticipated successive oxidations, more especially of a neutral one succeeded by an alkaline and acid one respectively, and an alkaline oxidation followed by one in acid solution.

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It was found, however, that on oxidising an organic or other oxidisable solution by a large excess of permanganate in acid solution, the results generally came out much too high, even for perfect oxidation, which indicated a loss of oxygen due to the presence of manganese dioxide. In order to prevent or diminish the loss, a ferric salt was added to the permanganate solution, the iron acting as accelerator in the presence of much permanganate and little manganese dioxide, and a retarder when the conditions were reversed. The ferric salt is really an accelerator, but it has the power of neutralising the action of the manganese dioxide after a certain excess has been formed. The accelerating action of iron in presence of much permanganate may be checked by the addition of sodium phosphate to the solution.

The author has based a quantitative method of estimating organic products on the results obtained from this investigation. The method, which is described in detail in the original, is applicable to the estimation of commercial organic substances, the determination of the organic matter in potable waters and in the waste liquors from works employing organic products, whilst for the estimation of alcoholic solutions when largely diluted, it is more rapid than the sp. gr. method.

In the second part of the paper, the author treats of the oxidation of organic substances by means of manganese dioxide in acid solution, as well as of oxidations by permanganate in neutral and alkaline solutions, and of analytical methods derived therefrom. D. B.

The Stalagmometer: a New Method for the Determination of Fusel Oil in Spirituous Liquors. By J. TRAUBE (Ber., 20, 2644-2655). The author previously described (Abstr., 1886, 743) a method for determining fusel oil in brandy by observing the height of the solution in a capillary tube. In the present paper an apparatus,

called a "stalagmometer," is described by means of which the percentage of fusel oil is determined by counting the drops contained in a known volume of liquid. As in the older method, the brandy is first diluted so as to be about 20 per cent. It is then put into the stalagmometer, and the number of drops from a given volume observed and compared with the number obtained from the same volume of pure 20 per cent. alcohol. An excess of 16 drop to 100 c.c. of liquid shows the presence of 0.1 per cent., an excess of 3.5 drops, of 0.2 per cent. of fusel oil. 005 per cent. of fusel oil can be determined readily and with certainty.

To increase the delicacy of the method, the proportion of alcohol to fusel oil must be diminished. This is done in the following manner :-300 c.c. of the liquid to be examined (diluted to 20 to 25 per cent.) is shaken in a funnel with 110 to 120 grams of pure ammonium sulphate, and left until two layers are formed; the lower layer, which contains very little fusel oil, is drawn off and shaken with two to three drops of ethyl alcohol or some crystals of ammonium sulphate. In this way the rest of the fusel oil is obtained as a separate layer. These upper layers are now mixed, dissolved in water, and distilled to about two-thirds. The distillate is made up to 110 c.c., the alcohol determined by means of a Westphal's balance, and the number of drops contained in the volume V by means of the stalagmometer. The latter number is compared with that obtained from pure spirit containing a known amount of fusel oil.

A sketch of the apparatus is given, as well as results obtained by means of it. These show that the method is as accurate as that previously described (loc. cit.), the new method having the advantage of being more easily worked.

N. H. M.

Assay of Commercial Carbolic Compounds. By J. MUTER and L. DE KONINGH (Analyst, 12, 191-195).-Carbolic Powders.-Where the phenols exist in the uncombined state, they are extracted by methylated spirit from 75 grams of the powder. Where the powder contains a lime base, a preliminary thorough trituration with a small excess of dilute sulphuric acid is necessary. The alcoholic extract is mixed with 200 c.c. of a 5 per cent. solution of sodium hydroxide, and the mixture is then evaporated to half its bulk. At this point any tar oils and naphthalene will separate and are to be filtered off. The filtrate is further concentrated to 50 c.c. and transferred to a graduated tube. This, which is known as Muter's carbolimeter, is wide in the lower portion. At 65 c.c. it is narrowed to a neck, which is graduated up to 110 c.c. in 0.25 c.c. divisions. It is stoppered, and is furnished with a long, thin, stirring rod, the volume of which must be allowed for. The solution is made up to 65 c.c., 25 c.c. of strong hydrochloric acid are slowly added with stirring, and then enough dry common salt to render the phenols insoluble. The tube is plunged into water of 15.5° and the volume of the phenols read off.

Liquid Carbolic Acid.-If this contains excess of water, it will not give a clear solution with three volumes of benzene. The amount of

water is ascertained by shaking 20 c.c. of the sample with 80 c.c. of a saturated solution of sodium chloride, and observing the diminution in volume. Tar oils are estimated by shaking 20 c.c. with 80 c.c. of soda solution (5 per cent.), and a small quantity of benzene (10 c.c. for dark specimens, less for pale ones). The increase in the volume of the benzene gives the amount of tar oils. The remainder is taken as phenol and cresols. M. J. S.

Acidimetry with Red Wines. By TONY-GARCIN (Compt. rend., 105, 577).—When red wine, prepared in the ordinary way and not more than a year old is mixed with sodium hydroxide solution, the colour changes to carmine, which becomes deeper and duller and passes into violet-black, which afterwards becomes black, without any tinge of violet, and then changes to green, with formation of a dark, flocculent precipitate. The point at which the colour is brownishblack, without any tinge of violet or green, is the point of exact neutralisation.

C. H. B.

Dairy Products. (Bull. U. S. Agric. Depart., No. 13, 1-128).— Butter and its Substitutes.--A series of micro-photographs is given, showing the appearance presented by butter, &c., when examined by polarised light. The black cross described by Hehner and Angell is seen in all the specimens of butter prepared by boiling and slow cooling, and is almost uniformly absent from the crystals obtained from the other fats, nevertheless it is shown by some specimens of butterine and oleomargarine from Armour and Co., Chicago, as well as in a slide prepared from beef suet "oleo oil," by dissolving in hot alcohol, and cooling slowly, thus confirming the opinion that it is not to be trusted as a characteristic of genuine butter.

The following method for determining the melting point of fats is described :-Thin discs are obtained by dropping the melted fat on to a piece of ice. One of these is placed in a test-tube, the lower part of which contains boiled water, and the upper part strong alcohol. The disc floats between the two liquids. The tube is then warmed in a water-bath, whilst the temperature of the contents is taken by a thermometer with small bulb, situated just above and close to the disc, and kept in motion like a revolving pendulum. The temperature at which the disc contracts to a sphere is taken as the melting point. It is necessary to examine the discs when freshly made, as they show a higher melting point if kept for 24 hours. When the water-alcohol tube is warmed before dropping in the disc, the contraction takes place some 6° lower than when the former method is followed.

Various modifications of Reichert's process are described. Davenport saponifies 5 grams of the butter with only 10 c.c. of alcoholic potash (containing 2 grams of KHO), operating in a flask from which the alcohol vapour is aspirated by a water-pump. Saponification and evaporation to dryness are complete in 15 minutes, and from the statement that genuine butters treated thus require on an average 28.8 c.c. of alkali, there would appear to be no loss of ethyl buty10

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