CHEMICAL NEWS, Sept. 29, 1876. New Chemical Test for Alcohol. The rainfall in 1872-3 was excessive, which accounted for the small proportion of nitrogen, and with regard to 1874-5 the number given was the result of a single analysis of all the monthly samples taken in quantities proportionate to the amounts of sewage distributed each month. Experiments made with bottled sewage and effluent water (kept for some time) showed that the total amount of nitrogen in the solid matter was not altered by keeping. The nitrogen in the effluent water was almost all converted into nitrates. This applied to filled bottles. In the case of unfilled bottles, a large quantity of the nitrogen in the sewage was lost, while in the effluent water it was only slightly diminished in amount, but was almost all oxidised to the condition of nitrates. Regarding the produce of the farm, the report stated that three plots of Italian ryegrass yielded respectively 58, 53, and 48 tons per acre. The highest average of mangold crops had been nearly 47 tons per acre. The nitrogen recovered in the crops was 20,558 lbs., equivalent to 30:34 per cent of that received in the sewage. Dr. Corfield concluded by stating that the lease of the farm being now up, and as another field of operations had not yet been obtained, the committee did not in the meantime ask to be re-appointed. Mr. E. C. C. STANFORD said he was sorry that the report of the Sewage Committee had developed very much into a mere report on irrigation. The committee had done valuable work, no doubt, but they had not treated this subject of sewage in the broad way to which it was entitled, and the result was that no question had been thoroughly sifted, save that of Mr. Hope's farm. Even in connection with that the committee had left out what sewage reformers wanted most to know, namely, the balance-sheet. Dr. GILBERT said he thought it would be found that, in the earlier years of the committee's work, they had investigated other processes besides that of irrigation, and had reported upon them, though, for substantial reasons, investigation was not followed up. Mr. Stanford had lamented the absence of a balance-sheet in connection with the report on Mr. Hope's farm. In reply to that he was quite free to admit that there had been a loss on the working, but his clear opinion was that, loss or not, the country ought to resort to irrigation. Mr. SPENCE said it had come to be a question between precipitation and irrigation, and the latter was nearly impracticable in the case of very large towns. His conviction was that precipitation by sulphates was the only true solution. Mr. W. R. W. SMITH had no doubt that for large towns irrigation was simply impossible. Five or six years ago, when the Rivers Pollution Commissioners said there was nothing for it but to irrigate, he told them he would make the prediction that no man then alive would ever see irrigation adopted in Glasgow. He took Dr. Chalmers Morton's figures, and calculated from these that it would require 20 square miles for the production of grass, and that it would take all the cattle in the three counties of Lanark, Renfrew, and Dumbarton to eat that grass; or, if they grew other crops, it would require 120 miles of land. Now, where were they to get such a space of ground for irrigation purposes? With regard to Mr. Coleman's paper (CHEMICAL NEWS, vol. xxxiv., p. 125), he had seen that gentleman's experiments and 137 considered them very satisfactory. It was urged against it that the manurial produce was not worth much, but here in Glasgow they were able to sell the veriest rubbish of city manure at a good price, and surely there could be no difficulty in selling a better quality. From what he had seen of Mr. Coleman's process, and of the ABC process, he had come clearly to the conclusion that very much could be done by using the cheap charcoal which lay in such abundance at our doors. But we must get rid of adopting a general principle to every particular case, and rather consider all the individual circumstances which would make it easy or difficult to deal with the sewage of a town. Much might be done too by getting the large public works to adopt the most available methods. Some further discussion followed, in the course of which the Lord Provost asked if the Sewage Committee would explain how irrigation could be adoped in the case of such a city as Glasgow, where there was a vast population, and where land in the neighbourhood was scarce and out of level with the town. Dr. GILBERT replied that no doubt an enormous quantity of land would be required in the case of Glasgow, but a mixed system of irrigation and filtration through soil might be adopted. ON A NEW CHEMICAL TEST FOR ALCOHOL. By EDMUND W. DAVY, A.M., M.D., Professor of Forensic Medicine, Royal College of Surgeons, Ireland, &c. WHILST making lately some experiments on molybdic acid, I observed that when a solution of that substance in strong sulphuric acid was brought in contact with alcohol, there is very quickly developed a deep azure blue colouratain) hitherto unrecorded, led me tion; and this fact, being (as far as I was able to ascerreaction to determine the cause of this production of to investigate the colour. As I found that the protosulphate of iron, and the protochloride of tin, two powerful deoxidising salts, produced a similar effect on this solution, there was but little doubt that it was due to the deoxidising action of alcohol on the molybdic acid. And I afterwards found that the blue substance which was formed in the case of alcohol possessed all the characters of the blue compound which is produced when molybdic acid or its salts are acted on by different reducing agents, whereby a substance consisting of five atoms of the metal molybdenum with fourteen of oxygen is obtained, which is usually regarded as a combination of the binoxide of molybdenum with molybdic acid, the following formula (MoO2,4M0O3) representing its composition. With certain precautions, which I shall presently point out, I have found that this reaction of alcohol on the molybdic solution stated is extremely sensitive, so that by its indications very minute quantities of alcohol, even when diluted with large proportions of water, may be readily detected. Thus, for example, if one part by volume of commercial rectified spirits be mixed with 100 parts of distilled water, and one small drop of this mixture be taken, the minute quantity of spirit contained in it can be easily detected by the deep blue colouration which will be immediately developed on bringing it into contact with the molybdic solution, employed in the manner about to be described. But this is not the limit of the delicacy of this test, for I have been able by means of it to detect the spirit in one drop of a mixture of distilled water and anhydrous spirit, in which the latter substance constituted only the one-thousandth part of its volume; and as the drop was found to weigh 6-10ths of a grain, the quantity of real or anhydrous alcohol contained in it would be less than the 1-1666th part of a grain of that substance. * A paper read before the Royal Irish Academy. 138 New Chemical Test for Alcohol. CHEMICAL NEWS, Though small quantities of spirit, even when consider- | amylic alcohols, those being the only ones I had for my ably diluted with water, will produce with the molybdic experiments. But it is more than probable that some at solution the blue reaction without the assistance of any least of the other alcohols may act in a similar manner; external heat, still, where very minute quantities, diluted however, the reaction is much more rapid and striking in with such large proportions of water as those just stated, the case of ethylic than in that of any of the otther are to be detected, it is necessary, for the success of the alcohols mentioned. I found also that certain salts of experiment, that the reaction should be assisted by a the radicles of those alcohols produced a somewhat gentle heat, and also that too great a dilution of the test similar reaction, as well as ethylic ether and aldehyd, solution with the liquid under examination should be and also several organic matters which are readily susavoided, as the blue colouration will not be developed if ceptible of oxidation. water be in excess; and even after it has been produced, the addition of a certain proportion of that substance quickly causes its disappearance. Such being the case, the best way of employing the test, according to my experience, is to place three or four drops of the molybdic solution in a small white porcelain capsule, and having heated them slightly, allow one or two drops of the liquid to be examined to glide or fall gently on the acid solution, when there will be developed, either immediately or after a few moments, the blue colouration. And where the alcohol is very largely diluted with water, it is better to continue the gentle heating of the test solution for some time, to concentrate it or expel as much water from it as possible, before adding the liquid to be tested, for, in this way, I have succeeded in detecting the spirit in mixtures so dilute as to give no blue reaction when added immediately to the test solution on its being simply warmed. regards the application of heat, I must observe that the temperature of the acid solution must not be raised too high, for if it be heated till the acid evolves its dense vapours, or begins to boil, the solution will of itself alone, from its partial decomposition, develop a more.or less blue colouration, which will become more perceptible on its cooling. But such an occurrence can be easily avoided by employing a water-bath as the heating agent; for I have found that a temperature of 212° F. is incapable of so acting on the test solution-at least an exposure of several hours' duration to that heat failed to produce the slightest blue colouration, and a much lower temperature than that suffices for the application of the test. As I should here state that the molybdic or test solution which I have generally employed was made by dissolving at a gentle heat I part by weight of molybdic acid in 10 parts of strong and pure sulphuric acid, but the exact strength of this solution as regards the amount of molybdic acid it contains seems to be immaterial. I may observe that the colouration produced in the reaction stated disappears after a variable interval of exposure to the air-a circumstance which is due, as I have ascertained, to the absorption of moisture from the atmosphere, and not to the re-oxidation of the molybdenum compound, as might have been supposed; for amongst other facts in proof of this, I may state that after it has thus disappeared, it may be readily restored either by expelling the water so absorbed by a gentle heat, or, more slowly, by placing the mixture under a desiccator, and thus removing it by spontaneous evaporation at the ordinary temperature. Such being the case, it is evident that, where the test solution has been too much diluted for the immediate development of the colouration described, expelling the excess of water by heating the mixture on a water-bath, it may be made to exhibit itself. But the necessity for such evaporation should, if possible, be avoided, which, in most cases, will be so by using only a drop or two of the liquid under examination, and by employing the strongest sulphuric acid in making the test solution; for it is very probable that much of the spirit contained in the liquid would be lost during its evaporation in the water-bath; besides, there would be some risk that the indications of the test might be more or less interfered with from particles of dust or organic matter getting into the mixture during that process. The reaction which has been described, I should state, is not peculiar to ordinary or ethylic alcohol, but is more or less readily developed by others at least I found it to be so in the case of methylic, propylic, butylic, and The circumstance that the reaction described is not peculiar to ethylic alcohol will, no doubt, lessen its value as a positive test for that substance; but a similar objection appertains to all the other known tests for that compound, as their indications are not peculiar to that alcohol alone, if we except, perhaps, Berthelot's test, which is founded on the development of benzoic ether by the action of benzoic chloride, along with caustic potash on ethylic alcohol. But, owing to the trouble attendant on the preparation of benzoic chloride, and some other practical inconveniences connected with the application of that test, it is not likely that it will ever come to be one of very general employment. The test, however, which I have brought before the Academy has this advantage over those already known, that it far exceeds (according to my experiments) any one of them in point of delicacy. And though the circumstance that the blue reaction produced in the case of this test is not peculiar to ethylic spirit lessens, as before observed, its value for the detection of that substance, this is just what renders the test of more general applicability; for by its aid certain impurities or adulterations may be at once detected in different substances or compounds, which in a state of purity should not contain any matter capable of acting on the molybdic solution employed in this test. I may refer to two important substances as examples, viz., chloroform and chloral hydrate, which are now so extensively employed in medicine and surgery for a number of useful purposes; and being agents of great power, it is of much importance that they should be free from the accidental impurities of imperfect preparation, as well as from the frauds of intentional adulteration, which may either impair their therapeutic value, or even increase the danger of their administration. For there can be but little doubt that in some instances the serious and even fatal effects resulting from their use may, in part at least, have been attributable to the impurities or adulterations of the chloroform, or of the chloral hydrate employed. Now, as I find that neither chloroform nor chloral hydrate, in their pure condition, have any apparent action on the molybdic test, but that many of their usual impurities develop the blue reaction, it affords us a ready means of testing their purity. Thus, as regards chloroform, one of its common impurities is ethylic alcohol, which it may contain either from imperfect preparation, or from fraudulent addition, the very high price of chloroform offering a great temptation to the unscrupulous vendor to increase its bulk or weight by the addition of alcohol, which so readily mixes with it. I have found that the molybdic test at once enables us to detect such an adulteration, even where it occurs in very small proportions in chloroform. Thus, in one experiment, I mixed 1 part of rectified spirit with 100 parts by volume of pure chloroform, and one drop of this mixture being brought in contact with three or four drops of the molybdic solution, previously warmed in a water-bath, gave an immediate deep blue colouration from the spirit contained in it; and, in a second experiment, with a mixture of 1 part of spirit to 1000 parts of chloroform, a single drop of the mixture, being similarly treated, developed a faint blue reaction. Indeed, so searching is this test as regards the purity of chloroform, that I was unable to obtain any sample of that substance in commerce sufficiently pure not to give a blue reaction with the molybdic test, owing to the minute quantities of volatile oils, and other impurities, they contain; and for CHEMICAL NEWS, Sept. 29, 1876. Development of the Chemical Arts. my experiments I was obliged to re-purify the commercially pure chloroform to obtain a sample which would give no coloured reaction with my test. In the case of chloral hydrate, it is stated that one of its usual impurities is the chloral alcoholate (a compound in which alcohol, instead of water, is combined with anhydrous chloral), and that this substance has somewhat different effects on the system from those produced by the hydrate. This compound, owing to the alcohol it contains, gives the blue reaction with the molybdic test, and I have found that where the chloral hydrate contained even so small a proportion of the alcoholate as 1 part in 1000 parts, a little of such a sample being taken indicated its presence when examined by the molybdic test; and it is probable that some of the other impurities which are met with in this important substance may be similarly detected. Those two examples are sufficient to indicate the use to which this test may be applied in the determination of the purity of different substances used in medicine, as well as in scientific research. Finally, I would remark that, as the reaction of molybdic acid on ethylic alcohol is so sensitive and prompt in its action, I entertain the hope that there may yet be founded on it, not merely this qualitative test, but likewise a means for the quantitative determination of that important alcohol. REPORT ON THE DEVELOPMENT OF THE CHEMICAL ARTS (Continued from p. 118.) Chlorine, Bromine, Iodine, and Fluorine. By Dr. E. MYLIUS, of Ludwigshafen. Potassium Chlorate.-No important change in the manufacture of the chlorate of potash has been introduced in the last few years. Now, as well as formerly, it is everywhere made according to Liebig's original process, hot milk of lime being saturated with chlorine, and the calcium chlorate, formed simultaneously with calcium chloride, being decomposed by potassium chloride. In England, which produces the bulk of the chlorate of potash of commerce, it is at present, according to Lunge, obtained in the following manner.† For saturating the milk of lime are employed two iron cylinders, lined with lead, connected with each other, and fitted with agitators. These cylinders communicate with each other, and with the chlorine still by means of tubes, and in such a manner that the contents of the one approach the state of complete saturation, whilst in the other any chlorine which may have escaped absorption is taken up by fresh milk of lime. As soon as perfect saturation has been attained in the first receiver, its contents are replaced by fresh milk of lime, and the current of chlorine is turned so that it may first enter the second apparatus. The solution of chloride and chlorate of calcium thus obtained has a rose-red colour, due, according to some authorities, to permanganic acid; but which, according to others (Crace-Calvert), appears also in the absence of manganese. In fact, this rose colour of the liquid is observed also as a sign of the complete saturation of the liquid where the chlorine employed is obtained without the use of manganese as at Kunheim's works at Berlin, where chlorine obtained by Deacon's process is used in the preparation of chlorate. The red liquid after clearing with chloride of potassium is evaporated down to "Berichte über die Entwickelung der Chemischen Industr'e Während des Letzten Jahrzehends." + Lunge, Dingl. Pol. Journ,, cxxcix., 489. 139 the sp. gr. 128 and allowed to crystallise. The liquid drawn off from the first crop of crystals is further evaporated down to 135, when a second smaller quantity of chlorate of potash is obtained. A portion, about 12 per cent, of the chlorate of potash remains in the motherliquor, which can therefore be treated as a source of chlorine. The crystals obtained are still contaminated with chloride of potassium and iron. To remove these impurities the crude salt is dissolved in the smallest possible quantity of hot water, 2.5 kilos. of soda are added to 10 hectolitres of the solution, and after the carbonate of lime and oxide of iron have been deposited it is allowed to crystallise. The crystals are dried in drying-rooms; the larger ones are sold without further treatment, and the smaller ones are ground between rollers. This process, in spite of every care, is sometimes attended with explosions. Lunge therefore recommends to crystallise the salt with constant agitation, and thus obtain it as a crystalline powder. In this manner the purification might also be more readily effected, as easily-soluble salts could be removed from the crystalline powder by merely washing with water. Whilst considerable quantities of chlorate of potash are manufactured in England this branch seems to be scarcely remunerative in Germany, where the same method of preparation is adopted. Several establishments have recently abandoned the manufacture. According to the experiments of F. Hobrecker, 100 parts of chlorate of potash require 44310 hydrochloric acid (20° B.); 772'0 manganese (65 per cent); 418'0 lime; 727 chloride of potassium (92 per cent; 2262'0 lignite. Bromine. However considerably the production of bromine had increased in the earlier decennial periods of its manufacture on the large scale, and however easily vast quantities of this body could be made available for the arts, its industrial applications, and consequently its production, have increased very little in the last few years. Whilst formerly the raw material for its preparation was derived from the mother-liquors of salt springs and from sea-water, especially that of the Dead Sea, which though richly bromiferous is too remote from the centres of consumption for chemical products, a new source has been discovered in the mother-liquors of the clearing salts (Abraum salz) of Stassfurt, which can be easily adapted to the demand. In spite of the quantity of bromine which can be obtained at Stassfurt it is merely a by-product of the potash trade, as, in consequence of the small demand and low commercial value, the cost of production falls little short of the market price. The utilisation of the Stassfurt "abraum" salts as a source of bromine dates from the year 1865, when A. Frank introduced this branch of industry in order the better to compete with the potash from kelp and from salt-springs, and also in the hope of superseding the use of iodine in the manufacture of colours. (To be continued). ON THE PREPARATION OF SOME COLOURED FIRES (BENGAL LIGHTS) USED IN PYROTECHNY. By SERGIUS KERN, St. Petersburg. In preparing coloured fires for fireworks by means of the usual formulæ given in many manuals of pyrotechny it is often very necessary to know the quickness of burning of coloured fires, so as in some cases, as decorations and lances, they must burn slowly, in other cases, as wheels, stars for rockets, and Roman candles, they must burn quicker. Working for some months with many compositions of such kind, I prepared three tables of coloured fires (red, green, and violet), where every formula with a higher number burns quicker than a fire with a lower number. For instance, No. 5 burns quicker than No. 6 140 Preliminary Note on Litmus. CHEMICAL NEW Sept. 29, 1876. and slower than No. 4. These tables will, I think, be obtained by evaporating the violet-red mother-liquor; it of much assistance in the preparation of fireworks. is a beautiful red, or, from many varieties, green, fluorescent substance, indifferent to acids. The litmus residue left after the above treatment with alcohol, and which is insoluble in that fluid, is digested with distilled water for twenty-four hours, after which the deep-coloured solution is evaporated to dryness on the water-bath, the residuary extract treated several times with absolute alcohol containing a little glacial acetic acid and again evaporated, until it forms a brown powdery mass. This brown powder is now extracted with absolute alcohol and acetic acid, whereby a large quantity of a scarlet-red body is dissolved, which resembles orceine and becomes purplered, in place of blue, with ammonia. The portion of the brown powder insoluble in the acidified absolute alcohol consists of the litmus colouring matter in a state of great purity-so pure, in fact, that by means of it the carbonated alkaline earths contained in spring waters may be titrated with as great delicacy as by the use of cochineal tincture, which is far from being the case with crude litmus. To get this perfectly pure, it is first washed with absolute alcohol, then dissolved in a small quantity of water and thrown into a large excess of alcohol; the flocculent purple precipitate collected and again thoroughly washed with alcohol. I have repeated Wartha's experiments as here stated upon some samples of litmus obtained from Bullock and Crenshaw, of Philadelphia, and said to have come from Pettitt, Aimee, and Co., Paris, France. My observations confirm h's results in every particular, save as regards the indigo. No deposit of indigo was obtained upon boiling the alcoholic tincture, not even after repeated ebullitions, with intervals of rest and cooling. The fluorescent body which he mentions is violet or purple, as I have obtained it, and gives a solution in alcohol of a similar colour, which shows a beautiful green fluorescence with sunlight, even when very dilute, and with the spectroscope gives a very characteristic absorption band in the green, together with an almost total absorption of the violet end of the spectrum. It is soluble in water, amylic alcohol, and common ether to some extent, extremely soluble in alcohol, but seems to be wholly insoluble in bisulphide of carbon, chloroform, retroleum-naphtha, and oil of turpentine, imparting neither colour nor fluorescent property to those liquids. The The solutions in amylic alcohol and in ether both exhibit a beautiful fluoresence, but the ethereal solution shows the absorption band in the green only very faintly, even when the solution is thoroughly saturated. solubility of the substance in both of these liquids is probably due to the trace of common alcohol, which they both contain, as found commercially. The body which resembles orceine shows a very faint fluorescence, and in alcoholic solution gives a spectrum in which the absorption is characteristic, and quite distinct from that of the last. It is slightly soluble in water, very soluble in alcohol, but seems to be insoluble in ether, chloroform, bisulphide of carbon, and petroleum-naphtha. The pure colouring matter proper of litmus is insoluble in alcohol ether, chloroform, bisulphide of carbon, and petroleum-naphtha, both in the cold and upon boiling; it is very soluble in water, and its aqueous solution yields an absorption spectrum differing from that of each of the preceding substances. This substance turns blue with ammonia, and seems more like the azolitmine of Kane than either of the other substances, but I obtained no ammonia from it by heating with sodic or calcic hydrates, that is, sufficient to show its presence by odour or by reaction upon reddened litmus paper. It yields in alkaline solution a beautiful violet lake with alumina, one of a pale violet colour with stannous acetate, and deep blue lakes with calcium and barium. The residue left, after extracting litmus with alcoh and then with water, is soluble to the extent of 8 CHEMICAL NEWS, Sept. 29, 1876. Improved Form of Gifford's Aspirator. cent in dilute hydrochloric acid, and the portion dissolved in this liquid consists of calcic and magnesic carbonates, free from colouring matter, in the proportions of about 90 per cent and ro per cent of the carbonates respectively. The residue, insoluble in dilute hydrochloric acid, consists mostly of fine sand, but yields some colouring matter to strong ammonic hydrate, and forms a solution of a blue colour, with a precipitate, red and gelatinous, somewhat like alumina, upon supersaturation with an acid. About 25 grs. of the pure colouring matter, 15 grs. of the body like orceine, and 10 grs. of the fluorescent body, were obtained per ounce of litmus. Diagrams of the absorption spectra yielded by these several substances I reserve for a second paper.—American Chemist. NOTES ON MINERAL ANALYSES. By W. M. HUTCHINGS. THE accompanying analyses of chrysocolla and copperpitchblende (Kupferpecherz) may prove of interest to some of the mineralogical readers of the CHEMICAL NEWS. The minerals are from Mexico and are imported into England in considerable quantity for copper smelting. The specimens analysed were very pure and homogeneous pieces, sought out from among a large quantity of freshly broken lumps of ore. The two minerals occur so thoroughly intermixed that it is difficult to find a piece of any size of either of them free from the other; so that it was necessary to break up the best pieces into fragments, picking out with forceps those which were perfectly pure of either kind. The chrysocolla is light bluish green in colour; hardness, 40. The copper-pitchblende is dark brown-almost black-with hardness 6'o. Large amounts of gypsum and clay occur with this ore. Copper carbonates are only present in small quantity here and there. When large lumps are broken open they often show drusy cavities in which the chrysocolla occurs botryoidal. This botryoidal chrysocolla is always coated over with a thin layer of quartz-sometimes amorphous, but more usually beautifully crystallised in very minute crystals. The powdered minerals were dried at 95° C. for some hours previous to analysis. 141 AN IMPROVED FORM OF ASPIRATOR. By R. H. RICHARDS. THE arrangement of this improved form of aspirator is shown in the figure. Hydrant water Airby Suction A glass tube should be bent of the form represented. This is essential, as it serves to break up the water jet into foam and thus start the suction. I find a hydrant pressure of about 20 pounds on the square inch, equivalent to 40 or 50 feet column of water, will easily exhaust to within Im.m. of the tension of aqueous vapour, and will cause a flask of water to effervesce as the dissolved air is disengaged. With traces of cobalt and manganese. Analysis of Copper-pitchblende. Per cent. 20.63 Silica, insoluble in Na2CO3 Copper oxide NOTICES OF BOOKS. Massachusetts Institute of Technology. President's Report for the Year ending September, 30, 1875. THIS establishment continues to be efficiently and successfully conducted. Turning, as a matter of course, to the "Department of Chemistry," we learn that "in the laboratories for quantitative analysis there has been a large and enthusiastic class," and that "the quality of the work done has, as a rule, been good." A variety of improvements and additions have been made. Thus "a careful selection of substances, the analysis of which would give an appropriate analytical training for any branch of chemistry, has now been made.' Extra balances have been procured, Bunsen pumps have been replaced by Richard's "jet aspirators," and a modification of the same arrangement is used to supply air to the blast-lamps. The facilities for organic and volumetri analysis, and for the determination of copper in ores |