摘要:

ANALYSIS O F A SAMPLE OF NEW ZEALAND COAL. BY OTTO HEHNER. Read bgiwe the Society of Public Analysts on the 20th June, 1803. BOME cliacudsion having recently taken place as to the value of New Zealand Coal as a fuel, the following results of a somewhat full analysis may be worthy of being placed on record. The sample to which the results refer consisted of large brownish black lumps, many of which showed woody structure; the fractures were conchyloid, the surface shiny and highly reflecting. It was interspersed with a considerable amount of an amber coloured resin. It burned readily, the flame being bright and very smoky. It consisted of :- When powdered it appeared chocolate-brown. Its ash was light and reddish brown. Water (loss at 212' F). ......................................... 20.09 Organic and Volatile Matter .................................... 75.19 Ash ........................................................4.72 100*00 The organic and volatile constituents had the following percentage composition :- Carbon ...................................................... 71.26 Hydrogen .................................................... 5.62 Oxygen ...................................................... 21.58 Nitrogen .................................................... 1-06 Sulph ur...................................................... -48 100~00 Silica ........................................................ 27.26 Alumina ..................................................... 26.48 Oxide of Iron ................................................ 12-98 Lime ........................................................ 2019 Magnesia ....................................................3.42 Sulphuric Acid.. .............................................. 9.47 Alkalies and Loss.. ............................................ 0.20 100-00 The ash was composed of:- -154 THE ANALYST. From these figures the composition of the coal itself calculates as under :- Water ........................................................ 20.09 Carbon ....................................................... 53.58 Hydrogen .................................................... 4.23 Oxygen ...................................................... 16.23 Nitrogen .................................................... *SO Sulphur ...................................................... -36 Silica ........................................................ 1.29 Alumina ................................................... 1-25 Oxide of Iron ................................................ -61 Lime ........................................................ -95 Magnesia ....................................................-16 Sulphuria Acid.. .............................................. -44 Alkalies ...................................................... *01 100~00 One ton furnished 8458 cubic feet of gas and 8 cwt. of coke. The very high proportion of water contained in the sample is very remarkable. It was so loosely combined, that even at ordinary temperature it gradually escaped, the coal crumbling to small pieces. The large amount, as well as the high percentage of oxygen characterise the so-called coal as a lignite, with which conclusion the physical characters of the sample are in perfect harmony. It was found to be insoluble in all ordinary menstrua, such as alcohol, ether, carbon dkulphide, benzene or chloroform, and neither attacked by boiling alcoholic potash, nor by fusing alkali. On heating it swells up considerably and undergoes decomposition, but does not fuse. The coal may be valuable as a, gas coal and for local consumption, but the large proportions of water and of oxygen militate against its use as a steam producer, only 58 per cent, of it being really combustible. The resin to which I have referred has not been further analysed.

ISSN:0003-2654    

DOI:10.1039/AN883080133b

出版商:RSC    

年代:1883

数据来源: RSC

摘要:

154 THE ANALYST. THE CAUSE OF A PECULIAR CONDITION OF SOME AMERICAN WATER SUPPLIES. By CHAS. R. FLETCHER, Lecturer on Chemistry, Boston University ; State Assayer, Massachusetts. Read before the Society of Public Analysts, on 27th June, 1883. THE peculiar, disagreeable, and truly alarming condition of the public water supply of the city of Boston, about a year ago, caused anxiety and alarm : for the cause of tho contami- nation was unknown, although sought for at different times by the chemist of the Water Commissioners ; and the bad flavor and odor caused illness and disgust ; and the water works had already cost several millions of pounds, and now the supply had been several times affected hy a similar flavor during several years, for a short period and in less degree. The valuable water supplies of eleven other cities had been also affected, since 1864, with probably the same trouble.In the winter of 1881-2, the Boston supply was very bad, not fit for domestic purposes on account of the odor and flavor. This has been commonly recognised under the name of ‘‘ cucumber taste,” as it resembles somewhat the taste of water in which cucumbers had soaked. But now the taste was worse, almost fishy, and often caused nausea, and always disgust.THE ANALYST. 185 It gave me pleasure to examine the water from a chemical point of view, with analyses, and report to a leading society of physicians, called together to discuss the situation ; for the physicians were aroused, and the people anxious. The only thing I noted was the higher percentage of albuminoid ammonia ” than that reported in previous analyses of this water. Expressing the belief that with an appropriation of a small sum the cause could be now detected in some low form of vegetable (possibly animal) growth, the sum was being raised, when the Water Commissioners were aroused by the public cry and compelled to order an investigation.A chemist had been employed to make analyms for years, but had never Eound the cause, possibly in consequence of unfavorable conditions. The common sense and scientific examination carried out in 1881-2 was successful, and is of great value. It was found that the bad flavor was intensified by heat, and also the odor-which was Blight when the water was cold, became very strong and disagreeable. Samples of the water were collected nnder many different conditiona, from tho suilPdce and at depth, and from all points of the supplies.It was found by chemical analysis of filtered and of unfiltered water, taken from the different positions in the lakes and reservoirs, l s t , That there m-as considerably more nitrogenous matter in suspension at the effluent gate-house (of the dorage basin which was particularly affected) than at the influent gate-house ; and 2nd, That there was not much difference in the amount of such matter in solution in the two specimens. UNFILTERED SPECIMENS. FREE AMMONIA. ALBUMIN. AMMONIA. Influent gate-house (10) . . . . . . 0.00 . . . . 0.272 Effluent gate-house (10) . . . . . . 0 026 . . . . 0.450 Influent gate-house (10) . . . . . . 0.034 .. . . 0.274 Effluent gate-house (10) . . . . . . 0.032 . . . . 0.296 The increase in the amount of free ammonia, noticed by comparing the latter table with the former, is due to the fact that the specimens stood one day longer in one case than in the other case, before tho analyses were msde, It was found that the matere undergo a gradual change by standing, and that the iesults of this change can be detected by Emalysis. The change consists in further oxidation of the nitrogenous matter, leading to an inorease in the amount of free ammonia, and finally to destruction of the material which imparts the taste and odor to the water. Chemical analyses were made of specimens from dl portions of the supplies-both those affected and those not affected by the bad flavor, It was found t h i t the chemical evidence was in accordance vrith that obtained by the senses.that is, the waters which tasted L g fishy,” ‘‘ metallic,” cucumbery,” contained more albu- minoid ammonia,” than those which did not carry the bad flavor. An attempt was then made to determine whether the substance which caused the taste was at the bottom of the lake or not. The mud when fir& filtered from the water had no odor, nor the water any bad taste at such depth. The question at once suggested itself: Did the taste come from something situated on some other part of the bottom, or might it bo developed by oontact of the mud and bottom water with air ? A thin layer of‘the mud on a filter paper gave in half-an-hour the ~tlme odor, which incredsed for 8 time then disappeared.There was evidently something in the bottom mud FILTERED SPECIMENS. FREE AMMONIA. ALBUMIN. AMMONIA.386 TBE ANALYST. capable of giving the odor, by contact with air. A careful microscopio examination revealed plnots belonging to the Nostoc family in quantity. Some were separated but gave no odor. Spicules of a sponge were also noticed, and later an examination of the screens at the gate-house showed an amount of this sponge, with the grass and leaves which had collected there. The same bad odor was there more manifest, and a series of experiments showed that the odor came from this freslt uater sponge. All agreed that the odor from it was identical with the peculiar flavor of the water. The speoimen is known as Spongzllaj-luviatilis Anct.It abounds in some localities, easily decomposes, and gives then a very strong odor. By drawing off the water from one water basin, large quantities were found in some places growing on rooks, from which it was easily detached. The experiments connected with this investigation were conducted according to the English rules of chemical analysis. The best way to detect the odor in water but slightly affected was to pass a pint or so through ordinary filter paper. This paper will then reveal the odor, though it may be quite impossible to detect it directly, even when the water is heated. Indeed, it is in the hope that a knowledge of this trouble in America may be of service to the Public Analpsts of England that I have requested of the Water Commissioners access to the report, the substance of whioh is here presented, As this flavor bas been occasionally noticed since 1854 in this oountry, it is of peculiar interest in connection with the valuable statistics and discussions on water supplies of the Society of Public Analysts, England. In oonnection with this condition of the Boston water there were various representa- tives, unjustly dignifieil by the name of 6 L theories,” sometimes by intelligent, usually by ignorant men, who possessed practically no knowledge of the subject. The value of this successful investigation in stopping anxiety and alarm (for as soon as the cause was known, a remedy soon followed), in pointing out to other large cities the probable cause of a similar condition, and in regaining the respect of the press and the public for chemical analysis of waters, was large. This test is delicate, and may sever others.

ISSN:0003-2654    

DOI:10.1039/AN8830800134

出版商:RSC    

年代:1883

数据来源: RSC

摘要:

386 THE ANALYST. COFFEE AND CHICORY LABELLED AS A MIXTURE. AT a recent meeting of the Manchester and Salford Grocers’ Association, a case was mentioned which tends to show what the opinion of the Home Office is where traders have been convicted for selling this class of goods. The case was that of‘ a firm of grocers named J. N’Mitchell and Co., BRrrow-in-Furness, who weye slirnmoned before the local magistrate8 under the Sale or Food and Drugs Act, for selling a mixtute of chicory and coffee. The magistrates fined Messrs. M’Mitchell65 and costs, although it was proved that the article was labelled as an admixture of coffee and chicory, and that the defendants’ assistant told the person who purchased it that it was not pure coffee, but a mixlure of coffee and chicory. Messrs. M’Mitchell and Co., wrote to the Home O%ce on the subject, and received the following reply :- 6 6 Gentlemen,-I have laid before the Secretary of State your letter of the lpth inst., calling attention to the prcceedings against sou under the Sale of Foods and Drugs Ad, md I am to acquaint you that he must decline to interfere with the decision of the justices. I am, gentlemen, your obedient servant, A. F. U. LLDDELL.”

ISSN:0003-2654    

DOI:10.1039/AN8830800136

出版商:RSC    

年代:1883

数据来源: RSC

摘要:

THE ANALYST. 3.87 APPLICATION OF THE COPPER-ZINC COUPLE TO THE ESTIMATION OF NITRATES IN WATER. RY ROBERT BREWER LEE, B.Sc., F.S.C., Of Birkbeck Laboratory, Universal College, London. SOME time ago I had occasion to consider the most readily available methods of esti- mating nitrates in the process of water ana2gsis. Crum’s method by reduction to nitric oxide was found most satisfactory for regular use in the laboratory ; but we were also in need of a handy method applicable in circum- stances where few of the appliances of an analytical laboratory were accessible. In the Journal of t7te ChsmicaZ Society, vol. xxxix, page 100, Mr. Whiteley Williams describes a process of reducing the nitric acid to ammonia by a copper-zinc conple, and nesslerising a few cubic centimetres of the water so treated.On endeavouring to repeat Mr. Williams’ experiment, only inaccurate resdts were obtained. After trying various modifications of the method, I came to the conclusion that the following are the conditions of greatest accuracy. 1. The nitric acid should only be present in small quantity-bebt not more than 10 or 12 grains per gallon. Waters containing more than this should be proportionately diluted with distilled water. 2. The couple is most active in slightly acid solutions. I find it best to acidify with oxalic acid, which has the advantages both of precipitating the limd, and of forming an insoluble compound with the zinc. The method of procedure is as follows :-The couple is made by immersion of clean zinc foil in a 3 per aent. solution of copper sulphate for 10 -15 minutes.It is thengently washed, and about I square decimetre placed in a wide-mouthed stoppered bottle of 300- 400 C.C. capacity. About 0-5 gramme of oxalic acid is added, and the bottle filled with the water to be analysed. The reduction may then safely be assumed to take place in the cold in 24 hours. But if the bottle be heated in a water-biith to 5Eio-6O0 C. the redaction will be found to be completed in 19 to 2 hours. From 2 to 10 C.C. of the water are now oarefuily wibhiliawu iu a graduated pipette, made up to 50 C.C. in the Nessler glass with aiumonia-free water, and nesslerised in the usual way. The use of oxalic acid enables the temperature to be raised to 60° C. without loss of ammonia, and the reduction is then completed rapidly.The oxalic acid used muet of course be free from ammonia and nitric acid. Attempt# were made to use granulated zinc instead of zinc foil for making the couple ; but the couple so obtained was wsaker and more uncertain in its action, The following are the results of the experiments made. When not otherwise etated, I worked upon dilute solutions of potassium nitrate of known strength; but in the case of natural waters the figures obtained are compared with determinations by Crum’s method. As the work was with tt view to water analysis, the results are stated in grains per gallon of nitrio miid (N,O,).180 THE ANALYST. In the first seven experiments, granulated zinc was employed and the quantity of oxalic acid varied from 1 to 2 grams. N,O, present.N,O, found. 1. ............ 7.00 .............. 7.22 .............. 2. ............ 3.50 .............. 4-17 .............. 3. ............ 14-00 .............. 13.90 .............. ............ .... (a) 3.89 (B) 4-17 4.08 (Crum) 4. .... 5. ............ 3.03 (Crum) ........ 3.00 6. ............ 5.00 .............. 4-72 7. ............ 10.00 .............. 7.78 8. ............ 7-00 .............. 6.95 9. ............ 4.20 .............. 3.90 10. ............ 5.00 .............. 5.28 11. ............ 1.00 .............. -95 12. ............ 62.26 (Crum) ........ 43.36 13. ............ 62.26 .......... 61.31 After this, zinc foil was employed. .............. .............. .............. .............. .............. .............. .............. .............. ............................ .............. 14. ............ 17-90 (Crum) ........ 15.56 .............. 16. ............ 1.40 .............. 1.44 .............. 16. ............ 4.20 .............. 4.17 .............. 17. ............ 6 18 (Crum) ........ 6-46: .............. 18. ............ 1.44 (01 urn) ........ 1.44 .............. 19. ............ 5.97 (Crum) ........ 6.20 .............. for making the couple, Remarks. 2 hours at 504 C. 2 hours at 50" C. 20 hours in cold. 2 hours at 60" C. 24 hours in cold. 2 hours at 60° C. 24 hours in cold. 24 hours in cold. 2 hours at 60°. 48 hours in cold. 18 hours in cold. 20 hours in cold. 40 hours in cold. The water was diluted to 10 times its original volume, then stood on couple 20 hours in cold. 40 hours in cold. 2 hours at 550-60° C.2 hour8 at 550-6O0 C. 18 hours at 60° C. 14 hours at 60° C. lg hours at 60" C. In experiments 8 to 14 the quantity of oxalic acid varied from 0% to 1.0 gram; and In conclusion, I wish to record my obligations to Dr, Graham, in whose laboratory these in the last Ei experiments it was 0-5 gram. experiments were made. MILK ANALYSIS IN BOSTON, U.S.A. IN connection with extracts from Dr. Bell's new book on Milk Analysis, &c., printed on another page, the following analpee made during one year, by the Analyst of Boston, will, no doubt, be of interest to our readers, as showing the standard adopted in that city. No 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 MILK 14 Uream pel aent. P 8 2 4-6 4 4.5 7 5 7 7.5 6 4 5 7 9 6-5 7 ANALYSES MADE DURING THE YEAR, Total Fatty Solids soilas.matter not fat. 9.20 0.42 8-78 7-85 o 98 6.87 10.50 1-45 9.05 12-80 2.15 10.65 7.42 0.58 6-84 11-15 1.46 9 69 9.50 1.32 8.18 11.20 1-68 9-52 10.98 2.15 8-83 10.25 1.65 8.60 11-15 2.15 9.00 13.70 2.18 11.52 10 25 1.92 8 83 10 87 1.80 9.07 10.40 1-58 8.82 10.60 1.95 8-66 10.45 2.65 7 80 10-40 1-82 8.58 11.05 2.19 8.86 Water. 90.80 92.15 89.50 87.20 92.58 88.85 90.60 88.80 89.02 89.75 88.85 86-30 89-76 89.13 89 60 89*40 89.55 89-60 88.96 Per cent. of water aaasd. 16 35 20 40 15 25 15 15 20 16; pure. 20 16 20 20 20 20 16THE ANALYST. FOOD ADULTERATION IN FRANCE. The following Analyses were made at the Paris Municipal Chemical Laboratory, during the month of June, 1883 :- Nature of the Samples Anslyeed. Good* Wines ..............71 Vinegars ............ 1 Beers .............. 16 Ciders .............. - Alcohols and Liqueurs - Waters ............ 15 Milke .............. 44 Malt ................ - Buttere ............ 16 Oils ................ 3 Flours .............. 6 Sweetmeats.. ........ - Meats .............. - Preserves ............ 3 Salt, Pepper ........ 5 Chicory, Coffee, Tea.. - Chocolates .......... 1 Honeys ............ - Confitures .......... - Colouring MateriaIs . . 2 Syrups.. ............ 1 Dough, Bread.. ...... 1 TOYS .............. - T i n s . . . . . . . . . . . . . . . . 2 Pharmaceutical Goloured Papers .... - Spices .............. 8 ducts ............ Pro-} - Perfumery .......... 5 Various ............ 22 TOTAZ;. ... 220 - =zGGi .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. Bad. Not Injurious. Injnriou~ /--- .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. 663 .. .. .. .. .. .. .. .. .I .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. 0 . 0 . .. .. *. .. I. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. Totals. 553 5 21 6 14 1 41 414 17 8 13 3 1 1 ti 18 2 8 - - 9 7 s 8 - - 5 43 1,206 - .=

ISSN:0003-2654    

DOI:10.1039/AN8830800137

出版商:RSC    

年代:1883

数据来源: RSC

摘要:

THE ANALYST. 139 THE BUTTER AND CHEESE LAW IN THE UNITED STATES. As our readers may not have seen the law of Boston, which specirtlly relates to these articles, we print it below :- [CH~P. 292, ACTS OF 1881.1 AN AUT to prevent Deception in Sales of Butter and Cheese. Be it enacted, dc., as follows :- SECTION 1. Whoever, by himself or his agents, shall sell, expose for sale, or have in his possession with intent to sell, any article, substance or compound, made in imitation or semblance of butter or as a substitute for butter, and not made exclusively m d wholly of milk or cream, or containing any fats, oils, or grease not produced from milk or cream, shall have the words ‘( adulterated butter ; ” or if such substitute is the compound known as oleomargarine, then the word ‘‘ oleomargarine,” stamped, labelled, or marked, in printed letters of plain Romm type not less than one inch in length, so that said word cannot be easily defaced, upon the top and side of every tub, firkin, box, or package contahing any of140 THE AXALYS’E.said article, substance, or compound. And in case of retail sales of any of said article, substance, or compound not in the original packages, the seller, by himself or his agents, shall attach to each package so sold at retail, and delivered with said package to the purchaser, a label or wrapper bearing in IL conspicuous place upon the outside of snid package the mords l‘ adulterated butter,” or the word “ oleomargarine,” as herein provided, in printed letters of plain Roman type not less than one-half inch in length.SECT. 2. Whoever, by himself or his agents, shall sell, expose for sale, or have in his possession with intent to sell, any article, substance, or compound, made in imitation or semblance of cheese, or as a substitute for cheese, and not made exclusively and wholly of milk or cream, or containing any fats, oils, or grease not produced from milk or cream, shall have the word ‘ l imitation cheese,” stamped, labelled, or marked in printed letters of plain Roman type not less than one inch in length, so that said words cannot be easily defaced, upon the side of every cheese cloth or band around the same, and upon the top and side of every tub, firkin, box, or package containing any of said article, substance, or com- pound. And in case of retail sales of any of said article, substance, or compound not in the original packages, the seller, by himself or his agents, shall attach to each package so sold at retail, and deliver with said package to the purchaser, a, label or wrapper bearing in a conspicuous place upon the outside of said package the words “ imitation cheese,” in printed letters of plain Roman type not less than one- half inch in length. SECT.3. Whoever sells, exposes for sale, or has in his possession with intent to sell any article, substance, or compound, made in imitation or semblance of butter, or as a substitute for butter, except as provided in section one ; whoever sells, exposes, for sale, or has in his possession with intent to sell, any article, substame, or compound made in imitation or semblance of cheese, or as a substitute for cheese, except as provided in section two, and whoever shall deface, erase, cancel, or remove any mark, stamp, brand, label, or wrapper provided for by this act, or change the contents of any box, tub, article, or package marked, stamped, or labelled as aforesaid, with intent to deceive as to the contents of said box, tub, article, or package, shall for every such offence forfeit and pay a fine of one hundred dollars, and for a second and each subsequent offence a fine of two hundred dollars, to be recovered with costci in any court of this Commonwealth of competent jurisdiction ; and any fine paid shall go to the city or town where the offence was committed.SECT. 4. It shall be the duty of every inspector of milk to institute complaint for violating the provisions of this act whenever he has reasonable cause for suspicion, and on the information of any person who shall lay before him satisfactory evidence on which to sustain the same.It shall be the duty of said inspector to take specimens of suspected butter or cheesb, and cause the same to be analyzed or otherwise satisfactorily tested, the result of whiah he shall record and preserve as evidence; and a certificate of such result, sworn to by the analyzer, shall be admitted in evidence in all prosecu- tions under this act. The expense of such analysis or test, not exceeding twenty dollars in any one case, may be included in the costs of prosecution. SECT. 5. For the purposes of this act the terms ‘‘ butter ” and l1 cheese ” shall be underatood to mean the products usually known by these names, and which are manufactured exclusively from milk or cream, or both, with salt and rennet, and with or without coloring matter. SECT. 6. All acts and parts of acts inconsistent herewith are hereby repealed. PLASTER OF PARIS IN FLouR.-If we may believe the following, the adulteration law of Ckmany, stringent as it is, is not strong enough to prevent such adulterations as we in England, at least of late years, never meet with:--“Dr. Skalweit, the analyst of the Local Board of Health of Hanover, Germany, had occasion recently to examine two samples of flour. He found one to contain 7+ per cent. and the other 124 per cent. of plaster of Paris. The millar has been arrested.”-NilZsr.

ISSN:0003-2654    

DOI:10.1039/AN8830800139

出版商:RSC    

年代:1883

数据来源: RSC

摘要:

140 THE AXALYS’E. ERRATUM.-In the ANALYST of June, 1883, page 103, line 21 from top, imert the words less than ” before 1.8 per cent.”

ISSN:0003-2654    

DOI:10.1039/AN8830800140

出版商:RSC    

年代:1883

数据来源: RSC

摘要:

T€€E ANALYST. 141 THE ANALYSIS AND ADULTERATION OF FOODS. BY JAMES BELL, PH. D., &c., Principal of the Somerset House Laboratory. Part 11.-Published for the Committee of Council on Education by Chapman & Hall. INSTEAD of reviewing this book at present, we reprint from it for the information of Public Analysts, the description of some of the processes used in the Somerset House Laboratory in the analysis of milk, and especially the description of the process which is carried out there for the analysis of sour milk, -~ Total SoZids.-The determination of the total solid matter in fresh milk is a comparatively easy operation. Five grams of the milk are weighed in an accurately tared platinum capsule, which is placed on an aperture of a water-bath and at the end of about three hours, or less, when the residue is sufficiently dry, the capsule is removed to a water-oven to eomplete the drying.The capsule is afterwards weighed at intervals till a constant weight is obtained. I t is important that the bottom of the capsule should be flat, or nearly so, and that the size should be such that, after the whole of the water has evaporated, the dry residue will be left in the form of a thin film. It has sometimes been recommended, in order to facilitate perfect dryiug, that a known quantity of sand or pulverized glass should be added to the milk in the capsule ; but this, according to our experience, is unnecessary, if care is taken to employ a capsule of the description mentioned. Non:fatty 8olids and Fczt.-When the milk is fresh, a quantity of exactly 10 grams may be weighed in a platinum capsule containing a glass stirrer.The most suitable size of the capsule for this purpose is one having a diameter of 3 inches and a depth of 1 inch. The capsule is placed on an aperture of a water-bath, and its contents evaporated almost to dryness. It is of advantage to keep the milk well stirred during the process of drying, in order to insure that the solid residue be obtained in a condition favouiable for the complete extraction of the fat. The milk residue should neither be too moist nor too dry, as either condition tends to prevent the removal of the last traces of fat. If the evaporation has been carried too far, the residue may be carefully moistened either with a very small quantity of water, or of alcohol. When the proper point has been reached, the mass is treated repeatedly with ether, the stirrer being each time used to pulverize the solid matter which, in order to insure that no portion escapes the action of the solvent, should assume a fine state of division.The ether is used warm for the last three treatments. After each washing the ethereal solution of the fat is carefully poured off through a small Swedish filter not exceeding 89 inches in diameter. To remove the last traces of fat from the filter, the upper part is cut off, divided into small pieces, which are placed in the remaining portion of the filter in the funnel, and washed with a little ether. The filtrates are received into a tared beaker from which the ether is gently evaporated, and the fatty residue finally dried in a water-oven until the weight is constant.The capsule containing the non-fatty residue is placed on the open water-bath for two hours, and subsequently for two or more hours in a closed water-oven kept at 212QF. (1OOOC.), until a constant weight is arrived at. This result should be obtained in the time stated if the milk solids have been finely pulverieed in the process of fat extraction, The d~hm&~&ion of the fat, non-fatty solids and ash, should be made in duplicate ; and, $8 further &eGk on the &ndySiS, the tOh1 rtmOUd of &k solids may be as&ahed142 TEE ANALYST. ~~ ~~ in a third portion of the milk, which may afterwards be used for one of the determinationa of the ash. It ought to be observed that, for some reason, probably connected in some way with the presence of fat, the final weighing of the total mlids is seldom, if ever, so satisfac- tory as that of the non-fatty solids. In no case, therefore, would we advise that the non- fatty solids should be determined by deducting the weight of fat actually obtained from that of the total solids.ANALYSIS OF SOUR MILK. It not unfrequently happens that an analysis has to be made of samples of milk which have been kept for some time-that is, for a period of from two or three days to about four weeks-during which time the milk has become sour and coagulated. In such cases a slight diminution in the non-fatty solids will have taken place, as the result of an incipient form of fermentation which changes a portion of the milk-sugar chiefly into lactic acid, and, to a smaller extent, into alcohol and carbonic acid gas.It is, no doubt, owing to the formation of a little alcohol that the depreciation of the non-fatty solids is due, as milk- sugar ehanges into lactio acid practically without any loss of weight ; and as the acid is not volatile, its weight is correctly indicated on drying the milk. But the weight of the sugar decomposed by alcoholic fermentation is almost entirely lost, as the alcohol disappears on evaporation, and only the small portion of carbonic acid gas which is held in solution in the milk is retained on neutralizing the milk as after-mentioned. It is evident, therefore, that some allowance should be made for decomposition in the way of addition to the amount of non-fatty solids, according to the time the milk has been kept, in order to obtain a correct estimate of the oomposition of the milk before any change had taken place.It has been alleged that the fat in sour milk increases at the expanse of the albuminous matter ; but the results of cur investigation show that the statement is without foundation. It is not unusual to obtain from sour milk about *05 per cent, of fat more than from the same milk in the fresh state, but this arises partly from the fact that, owing to the diminu- tion of the non-fatty solids, 100 parts of the decomposed milk represent rather more than 100 parts of the milk in its original state, and partly from the greater ease with which the residue from neutralized sour milk can be brought into a fine state of division, thus enabling the ether to act more effectively in dissolving out the last trace of fat. In estimating the non-fatty solids and fat in sour milks, it becomes necessary to adopt a, modifiiation of the process given.for the analysis of fresh milk, as the lactic acid is soluble in ether, and would be found dong with, and increase the weight of, the fat ; and for the further reason that it is almost impossible to satisfactorily dry the milk in the presence of the free acid, without producing a serious loss in weight from decomposition.The following method has been found to give very accurate results : Three suitable platinum capsules, two of which are suppiid with glass-rods flattened at the ends, are weighed, and from 10 to 12 grams of sour milk, which hag been thoroughly mixed by being whisked for a few minutes with a loose coil of fine brass wire, are introduced into each capsule, and the weight immediately ascertained.The separate quantities are exactly neutralised with pure decinormal soda solution, and the number of cubic centimetres required noted against each quantity. The contents of the two capsules oontaining the glass-rods are evaporated nearly to dryness, or until the residue attaina the condition of a firm paste, a result which is promoted by occasionally stirring the contents towards the end of the evaporation,THE ANALYST. 143 ~- -~ The third portion is brought to complete dryness, and the amount of total solids and ash estimated. The fat is extracted with ether in the ueual way, and the non-fatty solids brought to complete dryness on the water-bath.On evaporation of the ether from the extracted fat no traces of any of the milk solids will be found in the fat, if the neutralization of the milk has been properly effected. When the weights of the non-fatty solids have been ascertained, a deduction must be made for the added soda solution. The increase of weight arising from the soda is shown in the following equation : C,H,O, + NaHO = C,H,NaO, +OH, Lactio acid + Soda = Sodic lactate +Water. Every unit, therefore, of acid is increased by one unit of sodium, less the weight of an atom of hydrogen, which it repIaces in the acid. This, reckoned according to the atomic weights, is equal to 22. When, therefore, decirmormal soda is used to neutralize the acid milk, every cubic, centimetre used will add *0022 gram to the milk solids, and this weight multiplied into the tota1 oubic, eentimetres used will give the amount to be deducted.A similar deddon is also made in the case of the total solids. The deduction to be made from the ash is in accordance with the fact that the soda added is converted into carbonate of soda on ignition of the miIk residue, and the factor for multiplying into the number of cubic centimetres of soda, employed is therefore *0058 gramme, The following ctcttual experiment wiIl illustrate the method : Milk t&en for total solids = 9.517 grams. PO G.C. -& soh-solution required to neutralize :. 7-0 x -0022 = -0164 grams. Weight of dry total solids = 1-1390 grams. Deduct .. . . . . -0154 .. Milk solids . . . . 1.1236 .. x 100 = 11.80 per cent. total solids. - 1.1236 9.517 - Milk taken for Solids not Fat. Fth Expe fiment. Milk . . . . . . = 8.223 gms. Soda solution required . . = 6.000 O.C. Dryresidue . . . . = *720gm. Deduct 60 x *0022 . . = -0132 ,, 07068 ,, - Dry fat .b I= .267gm. 0267 x 100 8*223 = 3.24 per oent. of fat. ArJhresidue . . . . Deduct 7*0 x *0053 .. Second Eqerimen Soda solution required . . - DBdnot 6.4 x 0022 .. - Milk . . . . . . = - - Dry residue . . . . - - 8.728 gms. 6.40 C.C. *765 gm. -01408 ,, 076092 ,, I_. *75092 X 100 8.60 per cent. of 8.728 '= { non-fatty solids. Dry fat .. = *285 gm. *2" 'Oo% = 326 per cent. of fat. 8.728 . . . . = 0.110 grams. . . . . = '0371 ,) 00729 ,, - .0729 x 100 9,~17 = 076 per cent.of Rsh. The chlorine in the ash is estimated with fi silver-nitrate. Required 3.0 C.C. to preoipitate the (21.- *00355 3'0 9G17 '** = *11 per cent. chlorine,144 THE ANALYST. It is impracticable accurately to estimate the non-fatty solids by first taking the weight of the dry total solids and deducting the weight of fat obtained from it, as it is difficult to get a constant weight for the dry solids when the fat has not been removed. It is necessary, therefore, to rely on the actual weight of the non-fatty solids, as these readily attain a constant weight without any sensible decomposition. The allowance to be made for the loss which takes place in the non-fatty solids of milk is based upon the actual loss which has been found to occur in numerous samples of milk which have been analyeed in a fresh state, and again at intervals, after the lapse of a certain number of days.The depreciation or loss is fairly uniform for the same period of the year: but the amount varies within certain limits with the ordinary atmospheric changes of temperature, a slightly increased rate of depreciation occurring on a rise of temperature. The loss of non-fatty solids is relatively greatest during the first week of keeping, the amount for that period being on the average a24 per cent. ; for the second week the loss averages -10 per cent. additional ; and for each day thereafter -01 per cent. According to this rate of allowance, the addition to be made to the non-fatty solids would be as follows for the number of days stated : 7 days .... -24percent. 14 Y 9 .. .. -34 ,, 21 *, .. .. -41 ,, 28 I * .. .. *48 ,, 35 9 , .. * . 5 5 ,, As already mentioned, a slight variation from these figures will be found, according to the conditions under which the milk has been kept ; but the difference, whether greater or less, is generally indicated by the acidity of the milk, reckoned as lactic acid. With a carefully conducted analysis in the manner above described, the error, if any, in making the allowance should not exceed -10 per cent. of the non-fatty solids, and, in the case of watered milk, the result should come within one per cent. of the quantity of water added, as previously estimated from the analysis of fresh milk. In the experiments upon the results of which these allowances are founded, the milk was kept in bottles filled to the extent of about three parts, securely corked, and maintained at such temperatures as might be ordinarily expected to apply to official samples retained for reference under the Sale of Food and Drugs Act. * * * * * * * c * Some tables of analyses of samples from individual cows and from dairiels are given, and the author says : I t will be seen from Table V. that in the case of individual cows the non-fatty solids vary from 8.00 to 11.27, the fat from 1.92 to 6.87, and the ash from -6% to 087 per cent., while in the case of dairy samples in Table VI., the non-fatty solids vary from 8.50 to 9.91, the fat from 2 95 to 5-14, and the ash from 063 to *78 per cent. The percentage of chlorine in the samples taken as a whole varies from 008 to -14 per cent. Although these variations are considerable, it cannot be affirmed that they cover eveq case of low non-fatty solids which is occasionally met with in the milk of an individual cow.

ISSN:0003-2654    

DOI:10.1039/AN8830800141

出版商:RSC    

年代:1883

数据来源: RSC

摘要:

TELE ANALYST. 145 REVIEWS. A dlanual of Chemical Analysis a8 applied to the Examination of Medicinal Chemicals. BY FREDERICE HOFFNAN, M.A., Ph.D., AND FREDERICE B. POWER, Ph.D. London : Churchill. THIS is the third edition of a work which has become a standard one in America, and is corrected so as to contain all the recent additions both to the American and German Pharmacopeias. It opens with a short description of general qualitative analysis, giving the usual courses for bases and acids, of which the former is the best, that for acids having the too common fault of a certain degree of vagueness. It has always struck RS as strange that, among the immense mass of books treating of qualitative analysis, there are so few where a really definite systematic- course for acids is clearly laid down, and yet in the hands of any practised analyst, such a course is really as well defined as the base one.Following this we have a treatise on volumetric analysis taking in acidimetry and alkalimetry; analysis by oxidation and reduction, with solutions of potassium permanganate, potassium bichromate, iodine and sodium thiosulphate ; estimation of sugar and precipitation by argentic nitrate. This chapter is well and concisely written, and includes a plain statement of the short method of calculation by equivalents used by practical men. Then follows a chapter on alkaloids and their separation by the Stas-Otto method. The various chemicals are then taken in alphabetical order, beginning with acetunt and ending with zinc valerianate, and under each is given, (1) a description of the article, (2) a qualitative examination for impurities, and (3) a quantitative test.I n these the lines of the various pharmacopaeias are chiefly followed, but frequently we find methods, especially quantitative, not usually given, and decidedly good and simple. Of course, a critical reader will every now and then be struck by an omission, such as, for instance, no mention of any other method of estimation of free sulphuric acid in vinegar than the old pharmacopeia idea of direct precipitation with barium chloride, and an allowance for possible sulphates in the water, altogether ignorhg the modern method described some years ago in THE ANALYST by Mr. Hehner. Then, again, in following the various official methods for bark analysis given by the authors, any analyst would find quinine makers very loth to bhy on his results.Taken, however, as a whole, the work is one which should have a place on the shelves of every Public Analyst as a very useful book of reference, and it would be all the more useful to us in England if we only had d e b i t e legal atandards laid down for the purity of medicinal ohemicals. Elements of Pharmacy, Materia Medica, and Therapeutics. THIS is an addition to the series of Medical Students’ Manuals, published by Mr. Renshaw, and we may say at once that for the purposes intended it is a useful one. I t commences with about 45 pages devoted to the instruction of the student in practical pharmacy and dispensing, which, although not sufficiently exhaustive to be of any real use to pharmacists, will yet be very serviceable to medical students, who, as a rule, are exceedingly deficient in this art, Following the general introduction we have a similar number of pages devoted to the ingredients and strengths of the various preparations found in the British Pharmawpia, BY WXLLIAM WHITLA, M.D.146 THE ANALYST.and tabulated for ready learning. As a whole, this part is fairly correct, but we notice in glancing through it several slips requiring correction in future editions (such as the rJtrength of Mistura Gentian@). Leaving the pharmacy, the author then takes up materia medica, and here the whole of the usual and many of the rarer drugs and chemicals used in medicine are taken alphabetically, their names, orders, habitats, preparations, and doses are given, but only in rare instances their exact composition.One of the few cases where the author ventures to give figures, ie in the case of Kino, which we are told contains from 70 to 80 per cent. of tannin, a statement oalculated to somewhat astonish analysts having much to do with astringents. So long as the book is strictly in its own line it is all right, but where the necessities of the work cause the author to touch on the allied sciences of botany and chemistry, then there comes a difficulty now and then. For example, on page 137 we read (‘ COLCHICI CORMUS (Colchicum Comm)-MeIanthacele. The fresh buEb about the size of a chestnut of” &c., &c. The italics are ours, and unless botany has very much altered, it used (in our student’s days) to be one of the very fist things to learn how to distinguish a bulb from a corm.Taking next page 119, we find it stated that, in making Berberice sulphas, the slaked lime is used to precipitate the alkaloid, while we have always viewed it as being employed to remove the excess of sulphuric acid, the alkaloid being sub- sequently thrown down by the ammonium hydrate. On page 157 there is a note, which would lead to a wrong chemical belief in the mind of a too oonfiding student, because we read that as mercuric chloride is decomposed by so many substances it is advisable to order it in plain solution, or in solution with iodide of potassium, thus bading to the inference that no chemical decomposition takes place when mercuric chloride is mixed with potassium iodide.Having thus pointed out a few things that at once appeared undesirable, let us now hasten to the final portion of the work, viz. : about 200 pages of therapeutics. Here, in our opinion, the author is quite at home, and we have rarely met with so complete and yet concise treatment of this important subject. Taken as 8 whole, we have no doubt that Dr. Whitla’s work will become exceedingly and deservedly popular among mediaal students preparing for examination, for whose use it is specially auitabIe, but to those seeking such information as to the exact chemical constitution of drugs, and the tests for the presence of their active constituents, as is usually included in st11 works on materia medioa, it is a barren soil, and, therefore not sufficiently deep in this respect for the use of analytical or pharmaceutical students.RePorts Of Triah for ikbder by Poisoning, with Chsmicd Introauction, and Notes the Poisons used. B Y G. LATHOM BBOWNE, Barrister-at-Law, s;ad C, (3. STEWART, Bt. Thnas’ ~ o ~ p i t a ~ , London : Stevens & Sons, Chancery Lane. IN ,the old original days of the Polytechnic and Mechanics’ Institutions’, the union of chemistry and senflation used to be very popular, but when the science and art teacGng came to be general, the sensation element died out, and the hard and dry facts of chemistry remained. Here, however, we have probably one of the most startling combintttions of science and sensation ever put together in one volume. The poisons treated of are Hydrooyania Acid, Strychnia, Antimony, Arsenic, and Aconite, and their use, or rather abuse, is illustrated by full reports of the famous trials in whhh they have figured.THE ANALYST.I47 Commencing with the almost forgotten trial of Tawell, the Quaker, for poisoning his mistress with prussic acid, attention is at once arrested, and the chemist reads with deep interest thS evidence of the experts of that day, and how, with their imperfect apparitue and methods they built up the evidenoe. Then comes the evidence for the defence, that the hydracyanic acid might have been taken unconsciously in the form of apple pips, and especially that of the scientific shopman at a chemist’s in the oity, who was called to swear that from the pips of 15 small apples he extracted sufficient prussic acid to produce two grains and a quarter of argentic cyanide ; the process being described as being that of (‘ a soft water bath, diluted sulphuric acid, and sulphate of iron.” But all this was in vain, and Mr.Tawell came to his deserved fate, having previously confessed his misdeeds, and proved the accuracy of the evidence for the prosecution. After two or three minor cases9 we come to strychnia and Palmer with the evidence of Drs. Taylor and Christison; to arsenic and Madeline Smith with the evidence of Professors Penny and Christison for the prosecution and Maclagan for the defence ; to antimony and Pritchard ; and lastly to aconite and Lamson with the evidence of Drs. Dupr6 snd Stevenson. Each case is first carefully detailed by Mr. Browne, and then MP. Stewart takes up the story and chemically criticises the scientificl evidence, showing the advantages or otherwhe of the processes employed, and bringing to light many speoial experiments bearing on the matter which he has made. A captious critic might here and there find a few faults of omiseion, but very few of oommission in Mr. Stewart’s part of the book. For instance, in the table of distinctions between morphia, and strycbnia by first adding sulphuric acid and then certain other reagents, such as potassium bichromate, &c., there is no mention of the beautiful reaction with malybdate, 80 characteristic of morphia. Setting aside such few pointg however, iMr. Stewart must be highly complimented on the very painstaking manner in which he has done his part, and the whole work forms exceedingly interesting reading to all interested in toxicology and forensic medicine. As a guide to barristers anxious to post themselves up in points to ask, rtnd to scientific witnesses to see the possible pitfalls to avoid, it will be invaluable.

ISSN:0003-2654    

DOI:10.1039/AN8830800145

出版商:RSC    

年代:1883

数据来源: RSC

摘要:

TEE ANALYST. 147 BIRMINGHAM AND ADULTERATION. Dr. Alfred Hill, Analyst for the Borough of Birmingham, reports that during 1882 he examined 321 samples, including 101 milks, 75 mustards, 43 coffees, 40 peppers, 30 flours, 6 bread, 12 teas, 4 butters, &c. Dr. Hill says that 58 of the samples purchased, or 18 per cent. were found to be more or less adulterated ; it is gratifying, however, to find that during the past ten years the proportion of genuine articles continues to increase, being this year 82 per oent., against only 36 per cent. in 1873, and greater than in any other year of the decade. The percentage of adulteration in Milk continues to decline, and now stands at 36 per cent., or less than half what it was in 1873, when it was 75 per cent. Of the101 samples bought: during 1882,36 had been tampered with, either by the addition of water, or the abstraction of cream, or by combination of both methods of falsification. Birmingham has had, for a long time, the unenviable distinction of exceeding dl the large towns in the extent of its milk adulteration ; it IS, therefore, dl the more satisfactory to find an improvement in this direction.Dnring the last ton years the amount of adulteration has never been so low as in 1882, exoept in the year 1876. The immense importance of milk as an article of diet, for children and invalids especially, renders it imperative on the authorities to make every effort to secure its purity. Of the 76 Mustards, 6 proved on analysis to contain an admixture of wheaten flour and turmeric, while 15: or 43 per oent.of the Colfees oontarned large quantities of chicory ; in several instances the vendors of the latter &ide had protected themselves by l a b e m the axtiole Mixture,”948 THE ANALYST. One of the Butters examihed was such only in name, and consisted entirely of Batterine, though sold as Butter. The other samples were quite genuine. The Teas all proved to be genuine, indeed so careful a supervision of thearticle at the ports of entry is exercised by the Government that it is difficult to obtain adnlterated samples from the retail dealer. Bread and Flour also held, as usual, a distinguished place among the other articles of food. It is a, fact, as gratifying as remarkable, that I have not met with an adulterated sample of either the one or the other during the last ten years. The pleasure of recording it is enhanced, when it 1s considered how important is the quality of the most universal of all foods in reference to the well-being of the great mass of the people, constituting for them, as it actually does, the stapIe of their daily food, aad indeed the veritable " staff of life." If it be possible to carry on so extended a business as that of a Baker or a Miller at once honestly and profitably, it is difficult to see any reason why the Mllkman or any other purveyor of food should not transact his business on the same lines.

ISSN:0003-2654    

DOI:10.1039/AN8830800147

出版商:RSC    

年代:1883

数据来源: RSC

摘要:

148 THE ANALYgT. PUBLIC ANALYSTS’ REPORTS. DR. H. J. A.LFORD, the Analyst for Somersetshire, reported at the Quarter Session held at Taunton, that during the quarter he had analysed 266 samples of food and drugs, among which were 50 of dairy produce, including 15 speclmens of butter. Of groceries he had tested 158 samples, viz, : 49 of tea, 9 of sugar, 15 of arrowroot, 9 of mgo, 3 of tapioca, 27 of pepper, 26 of mustard, 16 of coffee, and 4 of corn- flour. Of the various samples, he found 3 of mustard, and 3 of coffee adulterated ; but he added to his report that none of the adulterations were absolutely injurious to health. At Wiltshire Quarter Session the County Analyst reported that among other samples he had analysed a sample of salt butter forwarded from Marlborough, two samples from Malmesbury, and samples of butter and coffee from Trowbridge, all of which were genuine.At Berkshire Quarter Session the Public Analyst reported he had examhed 21 samples of coffee, butter, mustaid, and lard, 8 of which were not genuine. The Grocer says that the mention of the Analyst’s report at the Hereford Quarter Session generally provokes laughter in the couit, and at the last sitting of the Court, the Chairman (Sir Richard Harrington) said he believed the report of the Analyst was not nil this time. This was received with merriment. The Clerk of the Peace stated that the Analyst had reported that no samples had been submitted to him during the quarter. A similar state of things prevailed in Breconshire at the Quarter Session, the Publicz Analyst reporting th& he had during the past three months received no samples of food, drink, or drugs, for analysis. The Cheshire County Analyst reporting to the Court of Quarter Session, stated, that during the past quarter he had examined, amongst other samples forwarded to him, 9 peppers, 8 mustards, 7 coffees, 6 teas, 7 lards, and 5 butters. Of these, 4 coffees, 2 peppers, and 1 mustard were adulterated. CORRESPONDENCE. [The Editors me not responsible for the opinions of their Correspondents.] THE MILK CASE AT NANCHESTER, To THE EDITOR OF “THE ~ A L Y S T . ” Sir,-Please kindly correct the figure given in my letter in the July number as non-fatty solids of farmer’s milk. The figure should be 9.3 not 9.6. Pours, &a, C. ESTCOURT.

ISSN:0003-2654    

DOI:10.1039/AN8830800148

出版商:RSC    

年代:1883

数据来源: RSC