摘要:

ESTIMATION O F TANNIN IN TEA. BY ALFRED HILL, M.D., F.I.C. Read before the Society @’ Public Analysts, on 11th May, 1881. IN examining the later samples of tea which have been submitted to me for analysis, it occurred to me that it would be desirable to ascertain the quantity of tannin present, for although it has been already shown that this constituent of the tea leaf is very variable, and therefore that its quantity, unless large, is of little value as an indication of purity, or, unless very small, furnishes no proof of adulteration, yet a few more observations in the same direction may possibly be productive of aome good.96 THE ANALYST. I am not aware that Lowenthal’s improved method of tannin estimation has ever been employed in the estimation of tannin in teas, and as its superiority to all other methods as regards expedition, ease and accuracy is testified to by the best authorities, I determined to employ it. I t is regarded by Neuhauer, Oser, Eitner, Kathreiner, and H.R. Procter, who have all had a large experience with it, and who have all helped to perfect it, ap the best process for the estimation of tannin in barks and other similar materials, and it is therefore no doubt also best adapted for estimating the tannin in tea, in which, as in the tanning materials referred to, the tannin is associated with gallic acid and other substances which, like it and tannin, are readily oxidisable. As some others may wish to use the method, it may perhaps be advantageous to say a few words in explanation of its principle and mode of application, but for fuller details I would refer to the author’s original paper in the Zeitschrift fiir Anal.Chdmie, 1877, pp. 33 and 201, to a paper by F. Kathreiner, Dingler’s Polyt. Jownal, No. 227, p. 481, and to two excellent papers by Mr. H. R. Procter, in the Chemical Neir*s, vol. xxxvi., p. 68, and vol. xxxvii., p. 256. The principle of the process rests on the oxidisability in the cold of tannin and the associated compounds, the separation of the tannin by means of gelatine, salt and acid, and finally the oxidation of the associated compounds minus the tannin. The difference between the two quantities of the solution of potassium permanganate of known strength used in the oxidation processes is that necessary to oxidise the tannin alone. The following are the solutions required :- (1.) Solution of potassium permanganate, 1.333 grms per litre.Of this solution, 24.1 C.C. =0*06S grms. oxalic acid. = 0.041 57 grms. gdlotannic mid (Neubaiier). = 0,062355 grms. quercitannic acid (Oser). (2.) (8.) (4.) Solution of sulphindigotate of potassium of such strength that 20 C.C. require Dilute sulphuric acid (1 to 3 water). Gelatine solution made as follows : 12.5 grms. good transparent (pale) glue are steeped in cold water all night ; the superfluous water is then poured off, and the dish containing the swollen gelatine placed on the water-bath to dissolve or melt the swollen mass, which is then saturated with good table salt and made up to 1 litre with a saturated solution of salt in water. (6.) A saturated aqueous solution of salt containing either 25 C.C.sulphuric or 50 C.C. hydrochloric acid per litre. The following is a description of my plan of proceeding:-2 grammes of tea were completely exhausted by boiling with water, and the decoction when cold was made up to 600 c.c., and the titration proceeded with at once in order to obviate any change. If the decoctionmust be kept even till next day Lowenthal recommends the addition to it of a few drops of glacial acetic acid (or of phosphoric acid). 10 C.C. of the decoction = 0.04 grm. of the tea leaf were taken, diluted with about a litre of water, mixed with 20 c.c, of the indigo solution and 10 C.C. of the sulphuric acid solution and the permanganate solution added very slowly and with constant stirring. The completion of the oxidation is recognised, if the titration be performed in a beaker placed on a white ground, by the occurrence of a clear yellow tint, readily hit by a little practice ; from, say 9 to 10 C.C.of the permanganate for oxidation.THE ANALYST. or, when the operation is conducted as recommended by Kathreiner in a white porcelain basin, by the appearance c;f a faint rose tint at the edge of the yellow liquid. Having previously prepared another portion of the same decoction by removing from it the tannin, 50 C.C. of it are measured off and titrated with permanganate in precisely tbe same manner as just described. The mode of preparation is as follows :-lo0 C.C. of the decoction are mixed with 50 C.C. of the salted gelatine solution, and finally, after well stirring, with 100 C.C.of the salt acid solution. The tannin is thrown down in combination with gelatine, and, after standing several hours or all night, is filtered off; the filtrate should be perfect2y clear. Care must be taken to mix the tannin solution with the solution of salted gelatine before adding the salt acid solution ; because, as Lowenthal especially mentions, acids precipitate, partly at least, the salted gelatine. The time occupied by the titration of the original decoction should not be lese than four minutes, and by that of the filtrate from the tannate of gelatine six minutes, as the presence of gelatine exerts a retarding influence on the reaction. The following is a transcript from my note book of the results of an actual experiment :- A.-TANNIN AKJ, OTHER OXIDISABLE MATTERS. 10 C.C.decoction = 0.04 grm. tea * * ‘ / required 13.2 C.C. permanganate, 20 C.C. indigo solution acidified ... ... ... ... Ditto repeated ... 7 7 1 3 4 ,) 9 , 26.2 ... ... 19.8 ,, 40 C.C. indigo alone, acidified , I 9 , 20 C.C. = 0.08 grm. tea ... ... ,, 6.4 ,, 9 , ~ B.-~XIDISABLE MATTERS EXCLUSIVE OF TANNIN. 50 C.C. filtrate = 0-08 grm. tea 20 C.C. indigo solution, acidified ... ... ... ‘. * 1 required 11.8 C.C. permanganate. Ditto repeated ... ... ... , I 12.0 9 , t 9 2308 ... ... 40 C.C. indigo alone, acidified ,, 19.8 ) 9 ,, 100 C.C. = 0-16 grm. tea ... ... 9 , 4.0 9 , f , 6.4 x 2 4 2 . 8 C.C. 4.0 8.8 C.C. permanganate required by tannin in 0.16 grm. tea. 8.8 x 0.0026 =0*02288 *Oil288 016 -- -a143 grm. or 14.3 per cent.tannin. The calculation is based on Rochleder’s statement that the peculiar tannin of tea is identical with quercitannic acid, and on the employment of Oser’s factor for that acid, In order to save others trouble I may take this opportunity of pointing out what is evidently an error of inadvertence in the statement following the example quoted from Lowenthal’s original monograph by Mr. Procter in the Chernicd News, vol. xxxvi., pp. 59 and 60, and that Mr. Wynter Blyth, in his Manual of Practical Chemistry, has copied the error, Mr. Procter has omitted to divide the figures 9.1 by 2, the result of which is that 1043 C.C. permanganate are made to appear as equioalent to the tannin of98 THE ANALYST. 20 C.C. of the sumach decoction or to 0.2 grm. of dry sumach, whereas the quantity of permanganate required is actually 15.35 C.C.The last eight samples on the list I obtained from a large importer who gave me the particulars of description, and their genuineness as imported is undoubted. Green teas as a rule contain more tannin than black teas, but there are many excep- tions, as a reference to the list will show, and it is remarkable that the sample of black tea containing the largest quantity of tannin (No. 31) contains mme than the richest sample of green (No. 8). Mulder found 17.8 per cent. in Chinese green tea (Hyson), and 12.88 per cent. in Chinese black tea (Congo) ; also 17.56 per cent. in Java (Hyson), and 14.8 per cent. in Java (Congo). The average amount of tannin in the thirty-two samples, the analyses of which I submit, is 14.8.Mulder's results were obtained with dried tea, mine with undried, so that his average results and mine are very similar. Some results obtained by Mr. Wigner, and given in the Proceediiiys of the Society of Public Analysts, vol. i., p. 235, are very much higher than any I obtained, probably because the method of estimation employed was that by acetate of lead, which includes gallic as well as tannic acid. The amount of tannin in tea is seen not to be in proportion to price, while in astrin- gents used for t,anning it is so ; the esteem in which a tea is held seems to depend npon qualities appreciable by the taster rather than upon chemical composition as revealed to the chemist. I t is desirable that in the examination of teas, as in that of other matterp, uni- formity of procedure should be observed, so that the results of different experimenters may admit of comparison, which is impossible as long as one uses the gelatine process, another the acetate of lead method, and a third that of LoNenthal.As the latter is now much simplified and is comparatively easy, quick and certain, while it gives tho amount of tannin 8s distinguished from gallic acid, I trust that others will be induced by my own experience of the process to give it a trial when a suitable opportunity shall present. RESULTS OF TEA ANALYSIS. Mixed .. Mixed .. Black .. Mixed .. Mixed . . Mixed .. Black .. Green .. Black .. Green .. Green .. Black .. Black .. Green .. Black .. Green .. Black . . Green .. - Description. .. .. a . .. .... .. .. a . .. .. .. .. . . .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. a . 6 . .. .. .. .. .. .. .. .. .. .. .. .. .. .. . I .. .. Ash Total. 6.06 5-98 7.00 6.08 6.69 5.88 5.77 6-69 6-08 6-06 5-81 6-34 6.21 6.98 6-90 5.92 6-71 6.94 6.06 Ash Soluble. 3.50 3.78 3.34 8-64 3.41 3.56 4.24 4-20 3.86 4.14 4.01 3.90 3.59 4.34 3-46 3-86 3-05 3.31 3-52 Ash Insoluble. 2.56 2.20 3.66 2-44 3.28 2.32 1-53 2.49 2.22 1-92 1.80 2-44 2-62 1.64 3-44 2.06 3.66 3.63 2.54 Tannin. 15.93 16.57 7.80 11.05 17.55 12-35 13.65 24.98 12-35 20.80 24.05 12-35 15.02 21.13 8.13 19-60 1008 9.10 15-26 Extract. 35.5 28-00 33.25 36.25 34.25 35.50 -13.00 33-50 43.00 43.75 34-00 29.80 39-00 26.60 33.00 28.75 25-50 - -THE ANALYST. RESULTS OF TEA ,~XAT>Y SIS.- Con tinued. Description. . . . . . . . . -- . . . . . . . . . . . . . . . . . . . . . . . . - . . . . . . . . Medium Congou, Chinese (Black), cost total 2/0&, June 4th, 1880 . . hssam (Black), cost total 2/2, Jane 4th, 1880 .. .. . . .. Common Chinese Congou (Black), cost total 1/4*, June 4th, 1880 . . Finest Assam (Black), cost total 4/2, June 4th, 1880 . . . . . . Very Fine Gunpowder (Green), cost total 3/11, June 4th, 1880 . . Common Gunpowder (Green), cost total 1!8, June 4th, 1880 . . . . Capor Tea (Black), cost total 2/0, June 4th, 1880 . . . . . . S. 0. Pekoe (Black), cost total 2/4 June 4th, 1880 . . , . . . Ash To t d . ti 50 5.83 5.88 6.08 6.78 5.90 5 5 5 5.83 5-30 7-10 6.16 5.58 5-78 Ash Soluble. 3-72 3-05 3.9 f 3.44 3-50 3'44 3.18 3-08 3.92 3-88 4-00 3.92 3.63 Averages . . . . . . . . 6-17 3-65 Ash Insoluble. 2% 2.78 1.94 2-64 3.28 2.46 2.37 2.75 1.38 3-22 2.16 1.66 2.25 2-50 ~ Tannin. 14.30 8.13 17.88 9.10 14.63 6-83 6.18 7.45 18-85 20-05 18.50 26.90 16-60 99 Extract. - - 14.79 3f.27

ISSN:0003-2654    

DOI:10.1039/AN881060095b

出版商:RSC    

年代:1881

数据来源: RSC

摘要:

THE ANALYST. 99 SWEDIRH LAWS AFFECTlWG SALE O F POISONS. BY C. HEISCH, F.C.S., F.1.C. K~irn! Dejore the Society of Public dnnlysts, o n Jltrrclt I f ; t h , 1881. [CONCLT'UED.] PHOCLAMATION BY ROYAL BOARD OF HEALTH OF STOCKHOLM, 28th February, 1876. After a long preamble it gives a catalogue. .First.-Of poisonous matters which may only be aoId by druggists, or chemical manu- facturers who have prepared them, and only in conformity with rules laid down in Decree of January 6th.-Amygdalin, Chloride of Antimony, Metallic Arsenic, Arsenic Acid, Arseniate of Soda, and all Arsenical Salts other than painters' colours ; Arsenite of Potash and other Arsenites not being painters' coIours; Atropin and its Salts; Oil of Bitter Almonds, containing Prussic Acid ; Cyanide of Potassium, and Cyan.Salt, which is mixture of KCy and NaCy ; Prussic Acid ; all Cyanides, except those oontainiiig Iron, such as Red and Yellow Prussiate of Potash, Prussian Blue, &c. ; Digitalin, Phosphorus, Chloral Hydrate, Chloroform, Koniin and Salts ; Tartar Emetic, Antimonial Wine, Antimoninte of P&isli, and Emetic Salts in general ; all Bases extracted from Opium and Salts appertaining thereto ; Nicotine and Salts ; Picrotoxin ; all Mercurial Salts, Oxide, Chloride, and Sublimate ; StrFchnia ; Brucia and Salts ; Gulphides of' Arsenic, Orpiment, Realgar, CFtc. ; Oil of Sabine and other preparations ; Veratrin and Salts ; Vegetable Alkaloids, other than above ; Aconite, Colchicin, Sabadillin, &c., with their Salts or corresponding Extracts ; Belladonna Leaf, Boat, or Extract ; Bitter Almond Water, Extract Henbane, Prussic Acid Emulsion, Curare and Urare PoisonR ; DigitaliR Leaf, Extract, and Tincture ; Elaterium ; Ignatius100 THE ANALYST.Bean ; Indian Hemp or Extract ; Kalabar Bean ; Cocculus Indicus ; Croton Seeds or Oil ; Mezereon ; Lactucarium ; Laurel Water ; Lobelia Herb and Tincture ; Secale and prepara- tions ; Conium and preparations ; all preparations of Opium, Euphorbium, Veratrin, Hellebore, Nux Vomica, Sabadilla ; Scammony ; Cantharides and Extract, &c. ; Stramonium ; Strtphisagria ; Aconite Root, Leaf, or Extract ; Colchicum and preparations. Sscond.-Such poisons as may be sold by licensed dealers according to rules in Decree of January 6th.-Ammonia, Aniline, Baryta Salts, Litharge, Red Lead, Sugar of Lead, Strong Oil of Vitriol, Sulphates of Copper and Iron, Oxalic Acid, Salts of Sorrel, Ink Powder, Caustic Potash and Solution, Chloride of Zinc, and Chloride of Zinc and Ammonia, Bisulphide Carbon, Blue Vitriol, Blue Stone, Oxide Copper, Chromic Acid Oxide and Salts, Caustic Soda and Solution, Nitro-benzol, Mirbtlne Oil, Imitation Oil of Bitter Almonds, Oxalic Acid, Nitric Acid, Muriatic Acid, Nitrate and Oxide of Silver, Salts of Tin and Zinc, Concentrated Acetic Acid.Poisonous coloura, containing Zinc, Cadmium, Bismuth, Tin, Chromic Acid, Antimony, Lead, Copper, Mercury, and Arsenic. Those most usually used are mentioned, but all cannot be specified. WHITE COLOURS. White Lead, Hamburg White, Dutch White, Pearl White, Silver White, Slate White, Spanish White, Tin White, Venetian White, Bismuth White, Zinc White.GREY AND BLACK COLOURS. Lead Black, Iron Black, Copper Black, Black Cinnabar, Zinc Grey, all Coal Tar Grey and Black Colours when they contain arsenic, copper or other poigonous material. RED AND ORANGE COLOURS. Red Sulphide of Antimony, Red Lead, Realgar, Cinnabar, Vermilion, Orange Chrome, Red Chrome, Minium, Paris Red, Red Varnish Paints, Amarin, Berlin, Viennese and Fenambruck Reds, Sap Red, &c. Red and Yellow Tar Colours when they contain arsenic or other poisonous ingredients. YELLOW COLOURS. Antimony Yellow, Baryta Yellow, Cadmium Yellow, Lemon Chrome, Yellow Ultra- marine, Gamboge, Hamburg Yellow, Jaune Brilliant, Kassel Yellow, Imperial Yellow, Cologne Yellow, Chrome Yellow, Leipsic Yellow, Massicot, Mengel Yellow, Mineral Yellow, Neapolitan Yellow, New Yellow, Patent Yellow, Permanent Yellow, Picric Acid, Siderin Yellow, Steinbuhl Yellow, Verona Yellow, Zinc Yellow and Zinc Chrome, Brass Lacquer made with metallic salts.All Yellow Tar Colours which contain arsenic or any poisonous ingredients, Orpiment, and all Sulphides of Arsenic. BLUE AND VIOLET COLOURS. Azure Blue, Celestial Blue, Bremen Blue, Cerulian Blue, Sky Blue, Chalk Blue, Cobalt Ultramarine, Cobalt Violet, Copper Blue (blue verditer), King’s Blue, Mineral Blue, Neuberg Blue, Smalt, Thenand’s Blue, Violet, Lac and Zinc Blue. All Blue Tar Colours containing arsenic or other poisonous mbstances. GREEN COLOURS. Azure Green, Brunswick, Bremen, Cassilmrtn’s, Elsners and Cinnabar Greens, Eaglish, Ground, Cassel’s, Imperial and Cherryhill Greens, Cobalt Greens, Chrome, May, Mineral Moss, Neuwied’s, New, Qriginal, Parrot, Paris and Permanent Greens (Pickel a d Reseda), Rinmon’s, Scheele’s, Schweinfurt, Swiss, Emerald, Spanish, Turkish, Vienna, Victoria,THE ANALYST.101 Wurzburg, Zinc and Verdigris, Green and all Green Tar Colours containing arsenic or other poisonous ingredients. BROWN COLOURS. Hatchett’s, Chemical and Copper Browns, Copper Red Brown, Bismuth Brown, and I t is remarkable that all Coal Tar Colours contain arsenic or other poisonous matters, This very important sentence follows the list of colours :- Regarding the existence of arsenic in colours or paints, it has hitherto been supposed that this substance is found only in copper green colours.It is now known to exist in many other colours, amongst which are some of the brightest reds which are supposed to be heightened in brilliancy by arsenic, This poison is also found in many grey colours employed in the manufacture of paperhangings ; also in Aniline colours which have been carelessly purified. In these arsenic would not be suspected, and can only be found by chemical process. all Brown Tar Colours, containing arsenic or other poisonous ingredients. but no hint is given that any are in themselves deleterious. List of articles which may be used to colour confectionery :- Chalk, Starch (Potato or Arrowroot). Ivory Black, Lamp Black, Charcoal Soot, Indian Ink. ~ V H I T E COLOURS. BLACK COLOURS. RED COLOURS. (In Decree all Mercurial Salts are prohibited).Carmine, Vermilion, Cochineal, Red Sandal, Brazil wood, Currant Juice, Alkanet, Raspberry, Barberry, Saffron. YELLOW COLOURS. BLUE AND VIOLET COLOURS. Saffron, Turmeric, Annatto, Quercitron, Qusssia, Marigold, Persian Berries. Clean Ultramarine, Indigo, Archil, Purple Iris, Logwood, Wormwood Flowers, Bilberry, Elderberry, Sloes, Black Cherry, Mulberry, Black Currant. GREEN COLOURS. BROWN COLOURS. METALS. Spinach, Pistacio, or any of the above named yellows and blues mixed. Burnt Sugar, Coffee, Catechu, Chino, Liquorice. Gold and Silver Leaf, pure. The absolute prohibition of the sale of all paperhanginga, &c., containing arsenic having been found oppresive to tradesmen, in November, 1879, the following definition of what waB to be considered arsenical within the meaning of the Decree was published : No paperhangings to be sold if a piece of 50 Swedish square inches (68-2 English square inches) or less can by chemical means have produced from it motallic arsenic sufficient to produce a black or brown mirror in ec glass tube 2 millimetres (-04 inch English) internal diameter.Textile fabrics, lamp shades, &c., if 25 Swedish square inches show similar mirror. Candles, Sealing Wax, &c., if a sample weighing 5 Swedish orts (385.8 grs. English) can be made to show similar mirror.102 THE ANALYST. Chemists employed, to give certificates under hand and seal, accompanied by an hermetically sealed tube containing the mirror obtained as above, and also a piece of the paper, &c., large enough to identify it with the original goods, and to enable a further analysis to be made, in case of dispute, ar?d shall be accompanied also by certificate from the analyst that all his chemicals were duly tried by him and found free from arsenic. To come into force on 1st July, 1880. It is to be regretted that no more definite directions as to the productions of this mirror are given, or how much arsenic per piece of paper it is supposed to represent, as differences would be pretty sure to arise amongst analysts as to the meaning of a black or brown mirror, &c.

ISSN:0003-2654    

DOI:10.1039/AN8810600099

出版商:RSC    

年代:1881

数据来源: RSC

摘要:

THE ANALYST. ON MAUMEN~PS TEST FOR OILS. BY ALFRED H. ALLEN. Read bflore the Society of Public Analysts on 11th May, 1881. SOME years ago M. Mailmen6 published a method of testing oils which was dependent on the rise of temperature observed on mixing a known weight of the sample with a definite amount of strong sulphuric acid. The value of the principle has been confirmed by observers, who have also proved the approximate constancy of the results obtained. Maumenk's experiments were made by mixing 50 grammes of the oil with 10 C.C. (= 18-45 grammes) of concentrated sulphuric acid in a beaker, or large test tube,';: stirring the mixture with a thermometer, and noting the greatest rise of temperature produced. Fehling, and, under his direction Faisst and Knauss, operated in an exactly similar manner, but t h e j employed 15 grammes of oil to 5 grammes of acid.I n the latter mode of manipulating, the temperature obtained is somewhat less elevated, owing to the greater proportional loss by conduction and radiation. The acid should be gradually added from a burette or pipette, while the mixture is continuously stirred with the thermometer. The following figures show in a tabular form the rise in temperature observed by Maumend and Fehling respectively, when working the manner already described+ :- KIND OF OIL. RISE OF TEMPERATURE OBSERVED. Castor .. Olive . . Sweet Almond Bitter Almond Rape .. Colza Rape. . Arachis (Earth. Beech-nut . . Sesame .. Poppy-seed , . Hemp-seed.. Walnut . . Linseed .. Cod-liver , . Skate-liver Horse-foot .. Tallow oil . . . . . . . . . . . . . . . . . . . . . . . . . . -nut) .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. *. MaumenB. "C. .. 47 .. .. 42 .. 52.5 to 53.5 .. 52 .. .. 57to5a .. .. 58 .. .. 67 .. .. 65 .. .. 68 .. . . 74.5 .. .. 98 .. .. 101 .. .. 103 .. . . 102 to 103 . . .. 102 .. .. 515 .. .. 41 to 43.5 .. Fehling. "C . . . . . . . . . 37'7 . . . . 40.3 . . . . 55 . . . . . . . . . . . . . . . . . . . . . . . . 70.5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . * In the oase of linseed oil, and other oils giving much heat, it is necessary to use a somewhat tall beaker, as the mixture swells greatly owing to the gas generated. t My excuse for re-publishing in detail the results of other chemists is that many of the figures given in the test have not, to my knowledge, hitherto found their way into any English journal or book, and have not previously been correlated.THE ANALYST. 10s The original figures of Maurnen6 have been recently verified and added to by him, and those of Fehling have been confirmed by other observers, especially in the case of olive oil.Thus : MM. Faisst and Ihauss, employing Fehling’s proportions, observed a rise of 3 8 O C. in the case of pure olive oil, whilst with poppy-seed oil the rise was not less than 70° C. In mixtures of the two oils, the additional rise of temperature was regularly l * G o C. for erery 5 per cent. of the adulterant. Nearly all fatty oils, except oil of ben, and tallow and lard oils, produce a higher rise of temperature than olive oil, so that an excessive increase is a valuable indication of admixture, and even of its approximate extent.The results of Maumend and Fehling appeared so important that I thought it unfortunate that the list of oils examined by them was deficient i n certain important respects. With a view of verifying their results, and of extending them in certain respects, I have made a series of experiments by the same method, using in each case 50 grammes of the sample and 10 C.C. of sulphuric acid of 1.845 specific gravity. The following table shows the results obtained :- 20. Rosin Oil . . . . . . . . 1. 2. 3. 4. 5 . 6. 7. 9. 10. 11. 12 * 13. 14. 15. 16. 17. 18. 19. a. Kind of Oil. Olive Oil, believed to be genuine . . Best Salad Oil . . . . . . Nape Oil, Brown, German .. . . ,, German . . . . . . ,, Brown, East Indian . . East Indian . . . . Coti;bn Seed Oil . . . . . . Nig’lr Seed’bil . . . . . . . . . . . . Linseed Oil, East Indian . . . . ,, Baltic . . . . . . ,, Baltic . . . . . . Cod Liver Oil, pale . . . . . . Sperm Oil, genuine.. . . . . ,, genuine, finest . . . . ,, believed to be genuine.. Russian .. Oleo-naphtha ” . . . . Mineral Lubricating Oil . . . . Shale Lubricating Oil . . . . Specific Gravity at 15.5’ C. .. -9144 .. .. -9156 .. .. -9176 .. .. -9172 .. .. *916G .. .. .9157 .. .. -9885 .. .. -9283 .. .. -9267 .. .. -9326 .. .. .9317 .. .. -9341 .. .. -9870 .. .. -8811 .. .. -8778 .. .. -8826 .. .. -9050 .. .. *8921 .. .. -8894 .. .. *9739 .. Rise of Temperature. “C. .. 42 .. 38, 39, 39 . . 51, 55. .. 50.5 .. 51.5 . . 56.0 .. 60.5 .. 57,69 .. 81 .. 109 .. 109 .. 110,111 .. 113 .. 45 .. 46 .. 45 .. 3 .. 3 . . 4 .. 19 The oils from 3 to 12, inclusive, were obtained direct from the seed-crushers, and were certainly genuine. I have every confidence that the fish oils also were perfectly genuine and representative samples. On the whole, the above results confirm the value of MaumenB’a method, and in some cases his observations also, but in other respects there are rather marked discrepancies. It will be observed that the rise of temperature I obtained in the case of olive oil is exactly identical with the observation of MaumenB. The salad oil, No, 2, which wa8 of questionable origin, gave somewhat lower results in each of three determinations. Hence, it is difficult to suppose that the sample was otherwise than genuine.In the case of rape oil, it will be noticed that the two samples of German rape gave sensibly less heat than the East Indian samples, while these last scarcely rose to the temperature observed by MaumenB. On the other hand, the results obtained by me from three samples of linseed oil are all higher than that of Maumenk, and the same rcmark applies to the rise of temperatme obtained with cod-liver oil.104 THE ANALYST. It will be observed that the hydrocarbon oils produce much less heat on treatment with sulphuric acid, and that rosin oil is itself sharply distinguished from the shale and petroleum products. Maumend, in a very recent paper,4’ states that : ‘‘ Recently heated acid, without having lost the least trace of water, presents very different actions, at least so far as the disengagement of heat which accompanies them, from those produced by the same acid long prepared.The contradiction of this great fact by M. Berthelot does not appear to me to be well founded.” I am not quite clear what strength of acid Maumend employed, as I am unable to comprehend the term ‘‘ l’acide ordinaire 8 3 ~ 5 ~ densimetriques.” It may mean either acid of 1.835 specific gravity, or acid containing 83.5 per cent. of SO,. Maumend compares the temperatures produced by using this acid, with those obtained with the same acid recently heated to 320°, cooled, and employed at the ordinary temperature. With 6 C.C. of these acids, and 25 grammes of various samples of linseed oil (half the original quantities), Maumend obtained such results as 6 6 O and 148O; 6 5 O and 1 3 3 O ; 5 9 O and 1 4 6 O .With a view of confirming these interesting results, I have ascertained the heat evolved by mixing 50 grammes of certain of the oils in the foregoing list with 10 C.C. of the aame acid previously used, but which had been heated to boiling and partially evaporated in platinum, then cooled to the ordinary temperature, and used without delay. The folloming are the results :- No. KIND OF OIL. INCREASE OF TEMPERATURE, OC. 2 .. Best Salad Oil . . . . . . 38, 39, 39 . . . . 39.5 With old acid. With recently boiled acid. 3 .. Rape Oil . . . . . . . . 51, 55 . . . . 52 4 Rape Oil 50.5 . . . . 51 10 .. Linseed Oil . . . . . . 109 . . . . 108 11 .. Linseed Oil .. . . . . 109 . . . . 110 12 .. Linseed Oil . . . . . . 110, 111 . . . . 111 They might be extended, but in the face of the almost absolute agreement between the temperatures produced by the two acids, there is not much encouragement to pursue the matter farther. I can suggest no explanation of M. Maumen6’s results, unless it be that his acid really increased in strength by the heating, in opposition to his express statement to the contrary. A comparatively slight variation in the strength of the acid used certainly causes a notable difference in the rise of temperature.* I suspect on several grounds that the concentrated snlphuric acid used in France is not always of full strength. Maumend concludes his paper by stating that he maintains, in contradiction to M. Berthelot, that recently heated sulphuric acid gives different temperatures when mixed with water from that produced by old acid. On mixing 10 c.c of each of the acids used for the oil experiments with 20 C.C. of water, I found the rise of temperature t o be respectively 81° and 8 2 O C. I am indebted to Mr. Charles Harrison for the very careful manner in which, under my direction, he has made most of the experiments the results of which are recorded in this paper. * ‘‘ Sur l’action de l’acide sulphurique rbcemment chauffhe it 320’ et lea hui1es.”-Comptes Rendus, March 21st, 1881, page 721. t It would perhaps be a wise precaution always to employ recently boiled acid, so as to ensure its being of full strength. .. . . . . . . . . These results offer a direct contradiction to those of M. MaumenB.

ISSN:0003-2654    

DOI:10.1039/AN8810600102

出版商:RSC    

年代:1881

数据来源: RSC

摘要:

THE ANALYST. 105 SOURCES OF THE PUBLIC WATER SUPPLIES OF ENGLAND. Darlington, Stockton and Middbesbroug1a.-The water supplied to the three towns is identical in composition. I t is ottained from the river Tees, which rises in Crossfell, in Cumberland. The bed of the river is chiefly composed of carbon ferous limestone. Down to the pumping station the river is shallow and has a rapid flow over rock and shingle. I n its course it receives two important tributary streams-the Lune and the Balder. I t alRo receives the sewage of Middleton-in- Teesdale, Barnard Castle and Gainford, which have an aggregate population of about 8,000. The pumping stations are at Broken Scar, 2+ miles west of Darlington. The water is lifted into settling ponds, thence to filter beds of ordinary construction.Speaking of Darlington itself the filters somewhat lack efficiency, for ir flood time the water is seldom free from turbidity. There are practicalIy no storage reservoirs. There are small reservoirs attached to each works, which hold about enough for one day's consumption, so that the supply is really continuous. The works are in the hands of the Corporation of Darlington, and a Joint Water Board for Stockton and Middlesbrough. The high service supply is obtained from nn artesian well in Waterworks Street, having a bore 15 inches in diameter, and a depth of 112 feet into the chalk. 400,000 gallons are pumped dailg into mains which supply the higher parts of the town. The low service supply is surface water obtained from gathering grounds at Holy Wells, Burk's Hill, and Christchurch Park, and stored in reservoirs. This water supplies the lower parts of the town, In oases of fire the high service can be turned on to the low service pipes. The gathering grounds are mainly peaty moorlands. Ipswich has two water supplies, a high and a low service.

ISSN:0003-2654    

DOI:10.1039/AN881060105a

出版商:RSC    

年代:1881

数据来源: RSC

摘要:

110 THE ANALYST. LAW REPORTS. Whisky Adulteration :- Mr. Thomas George Mumford, proprietor of the ‘‘ Union ” Tavern, Mint Street, Borough, was summoiled before Mr. Slade by Mr. Edwards, the officer appointed by the Vestry of Saint George, Southwark, for selling to the prejudice of the purchaser an article of food, viz., whisky, which was not of the nature, substance, and quality demanded by such purchaser, it being reduced spirits more than 85 degrees under proof. Nr. Slade observed that publicans mere allowed to reduce spirits to the extent of 25 degrees, but 37 seemod rather too much. He asked Mr. Edwtlrds if it was adulterated with anytliiug worse than water. The certificate stated ‘‘ Not injurious to health.” The defendant said, in answer to the charge, that he had only recently taken the business, and lie was iiot aware that the whisky liad been reduced to that extent.He was only in a small way of business. Mr. Edwards replied in the negative. Mr. Hlade fined him lOs., and 12s. 6d. costs. Refusing t o Serve, uiid Assault :- At Hammersmith, on Saturday, Allen Mannering, oi Crofton Territce, Hammersmith. appeared to answer two sunimonses, one for refusing to sell a pound of butter to Henry Oatley, an inspector appointed under the Sale of Food Act, and the other for assaulting him in the execution of his duty. MY. Jones, clerk to the Fulharn District Board of Works, handed to the magistrate a certificate of the anslyst, stating that the butter contained 80 per cent. of foreign fat other than butter. After hearing the evidence, which showed that the defendant was not the owner of the shop, Mr.Paget dismissed the Summons for refusing to sell the butter, as he thought tlie purchase was complete. He, however, fined the defendant $5 for the assault. Mr. J. H. Cornall, M.R.C.S., has been appointed Public Analyst for the Borough of Warring t on. RECENT CHEMICAL PATENTS. The following specifications have been recently published, and can be obtained from the Great Seal Ofice, Cursitor Street, Chancery Lane, London. No. 1880 Name of Patentee. 3641 L. A. Groth . . . . 3644 J. C. Bloomfield . . 3731 B. Biggs . . . . 3745 P. $1. Justice. . 3765 E. G. Brewer 3861 N. G. Richardson 3867 B. Hofmann .. 3939 E. H. T. Liveing 3971 A. M. Clark . . 4017 & 4158 Ditto . . 4056 W. Thompson 4069 J. W. M.Miller 4094 W. Elinore .. 4192 G. P. Hardiiig 4303 T. Morgan .. 5337 E. D. Brunei .. .. .. .. .. .. .. .. .. .. .. .. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Title of Patent. Decomposition of Salts of Ammonia . . . . Piice. .. 6d. Manufacture of Cement . . . . . . . . . . 3d. Separation of Acetic Acid from Crude Pyroligneous Acid and Spirit . . . . . . . . . . 2d. Purifying and Whitening Oils and Fats . . . . 4d. Electric Lamps . . . . . . . . . . . . 112 Manufacture of Paper . . . . . . . . . . 2d. Manufacture of Oleine and Butterine . . . . . . 4d. Colouring Alcohol for Thermometers . . . . . . 2d. Dynamo-Electric Machines . . . . . . . . 10d. Saving Hydrogen Gas Generated in Cleaning Wire .. 6d. Manufacture of White Lead . . . . . . . . 8d. Preserving Animal and Vegetable Substances . . 2d. Extracting Copper and other Metals from their Ores 4d. 4d. Fire Extincteurs . . . . . . . . . . . . 6d. Electric Lamps for Engines . . . . . . . . 4d. Converting Nitrogenous Organic Substances . . . . BOOKS, &c., RECEIVED. The Chemist and Druggist; The Brewers’ Guardian ; The British Medical Journal ; The Medical Press ; The Pharmaceutical Journal; The Sanitary Record; The Miller; Journal of Applied Science ; The Boston Journal of Chemistry ; The Provisioner ; The Practitioner ; New Hemedies ; Proceedings of the American Chemical Society ; Le Practicien ; The Inventors’ Record ; New York Public Health ; The Scientific American ; Society of Arts Journal ; Sanitary Engineer of New York ; The Cowkeeper and DLLiryrnan’s Journal ; The Chemists’ Journal ; Oil and Drug News ; The Textile Record of America ; Sugar Cane; Country Brewers’ Gazette ; Smithsonian Report, 1879.

ISSN:0003-2654    

DOI:10.1039/AN8810600110

出版商:RSC    

年代:1881

数据来源: RSC