quantitative reaction, by means of which any desired substitution of chlorine may be readily effected in a large number of hydrocarbons. It consists of heating in a sealed tube the calculated quantities of hydrocarbon and phosphorus pentachloride, when the pentachloride is dissociated into the trichloride and free chlorine. The value of this means of substitution lies in the fact that, instead of the uncertain results so frequently obtained by the graduated use of free chlorine, it now becomes possible to obtain a quantitative yield, in a form that is easily separable, of the particular chlorine derivative desired.

R. T. Thomson publishes two methods for the estimation of aluininum in the presence of a large proportion of iron. One is for use when but little, the other when a larger proportion of manganese is present. Both depend upon the reduction of the iron to a ferrous state and the precipitation of aluminum as a phosphate by means of ammonia and ammonium acetate. Franke describes the preparation of manganic anhydride, MnO.. To obtain it, dry potassium permanganate is added to well-cooled sulphuric acid; the green solution formed is either heated to 50° C., after addition of a lit tle water, or better, allowed to flow, drop by drop, on to calcined soda. Violet vapors of manganic anhydride are evolved, and condense in the receiver to a dark amorphous mass. When heated at 50° it volatilizes in violet vapors, with partial decomposition into manganic dioxide and oxygen. If heated more strongly, it is completely decomposed into those substances. It dissolves only sparingly in water, imparting to it a deep-red color. It is also a most vigorous oxydizing agent.

Industrial Chemistry.-Mr. A. E. Fletcher, chief inspector under the Alkali Works Regulation Act, describing in the British Association the present position of the alkali manufacture, said that Leblanc's process had withstood the attacks of all rivals, and that, although the competition against it was fiercer than at any previous period, he thought that it would maintain its position for many a year to come. During the last ten years slight alterations had been proposed in the proportions to be used of the three ingredients forming the charge of the black-ash furnace-the coal, brimstone or chalk, and sulphate of soda-and in the method of throwing them in the furnace. The main process, however, of fusing these materials together, and, when cold, lixiviating the mixture for the extraction of carbonate of soda, is followed almost exactly as was proposed by Leblanc, now almost a century ago. It must be acknowledged that this process is seriously attacked by another, so far as the manufacture of carbonate of soda is concerned, and it would have been by this time completely driven out of the market by its rival, but for the importance of its by-product. Bleaching-powder had not as yet been made in connection with the ammonia process. Three methods were, how

ever, proposed, and were on their trial for the attainment of that end. If bleaching-powder could be produced by either of them at a moderate cost, the older alkali process could no longer stand its ground.

Traube has made some new researches on the part taken by water in the combustion of carbonic oxide, which have a double interest in their bearing on the properties of watergas, and of the peroxide of hydrogen. The peroxide of hydrogen is constantly finding increasing application, more or less diluted with water, as an oxidizing, bleaching, and disinfecting agent. It is used for the bleaching of bones and ivory, wool, silk, feathers, and hair; in housekeeping for removing wine and fruit spots from white cloths. It stops all kinds of fermentation, and is therefore a good preserving agent. Destroying all micro-organisms, it is valuable in the treatment of wounds and skindiseases. To prevent decomposition, however, the solutions of this substance must be kept at a low temperature and protected from the light. According to Dixon's experiments, a perfectly dry mixture of oxygen and carbonic oxide can not be exploded by any ordinary means; and ignition will not take place until a certain quantity of the vapor of water is introduced. Traube has confirmed these important observations, and has found, further, that carbonic oxide already inflamed is immediately extinguished in a perfectly dry atmosphere. He found, further, that carbonic oxide, even at a high temperature, will not decompose water, so that no trace of carbonic acid or hydrogen is developed under those conditions. But hydrogen has a reducing action on carbonic acid at a red heat; and if we pass an electric spark through a mixture of the two substances, carbonic oxide and water are formed. Traube, therefore, concluded that water plays a similar part in the combustion of carbonic oxide at a red heat to that which it plays, according to his researches, in the slow combustion of the baser metals; that is, that in both cases it is decomposed with the formation of peroxide of hydrogen. Carbonic oxide, which alone can not decompose water, exerts this action with the aid of oxygen. In fact, direct experiments show that the flame of carbonic oxide when brought in contact with water gives off so much peroxide of hydrogen that very intense reactions are produced with potash permanganate or zinc iodide, and sulphate of iron, or with chromic acid and ether.

Cholesterin is a fat which occurs in the feathers of birds and other animal coverings, and is present in considerable proportions in wool. Because of its uncleanness and unpleasant smell, and of its containing 25 per cent. of free fatty acid, it has to be removed in the preparation of the fabric; while hitherto it has been regarded as of no value except as a combustible or as the raw material for illuminating gas. The clear fat arising from the combination of cholesterin with the fatty acids has

been found, however, to possess some valuable properties. It is perfectly neutral, and not saponifiable with alkaline hydrates, while it is capable of taking up an equal weight of water, and forming an extremely pliant soft mass absorbable by the skin, which can be incorporated with various medicaments. Liebrich has closely studied this substance, which he calls "Lanolin," and having been manufactured commercially and introduced to the trade, it has in a short time come into quite general demand as a basis for salves and cosmetics.

Mr. C. O'Neill, in a British Association paper on "the extent to which calico-printing and the tinctorial arts have been affected by the introduction of modern colors," after remarking upon the continuing multiplication of the modern colors, said that none of them, except alizarene and its allied blue and orange derivatives, could be said to be fast colors upon cotton in the sense that madder and indigo are fast. At the same time many of them were fast enough for the purposes to which they were applied, and had contributed in calico-printing to give a variety of coloring which had no doubt extended the demand for printed goods. The idea that all new dyes were bad dyes was not warrantable. Whatever might be the true state of the case with regard to cotton fabrics, the author considered that the introduction of modern colors in the dyeing of fancy silk and woolen styles had proved of very great advantage.

The search for means for improving artificial lights of all kinds has led to the utilization of rare earths which, like lime and magnesia, have great light-emitting properties combined with permanent powers of resistance. Zirconia thus figures as the wick in Linneman's oxygenated gas-lamp, and in Auer's new incandescent gas-light, a combination of similar rare earths is said to be employed.

Dr. C. Fahlberg, of Johns Hopkins University, read a paper in the British Association on "Saccharine, the New Sweet Product from Coal-tar." The new extract, which was two hundred and fifty times sweeter than sugar, had become an article of commerce, and was manufactured in Germany. Experiments upon animals and men, and nine years' use by the author, had proved it to be entirely harmless.

Charles L. Bloxam describes the following as a characteristic and delicate test for indentifying strychnine: the alkaloid, on a glass slide or a porcelain crucible lid, is dissolved in a drop of dilute nitric acid, and gently heated; to the warm solution a very minute quantity of powdered potassium chlorate is added, which will produce an intense scarlet color; one or two drops of ammonia will change this to a brownish color, giving a brownish precipitate. The mixture is then evaporated to dryness, when it leaves a dark-green residue, dissolved by a drop of water into a green solution, changed to orange brown by potash, and becomes green again with nitric acid. These last

changes of color may be repeated any number of times. None other of the commonly-colored alkaloids which were tried could be mistaken for strychnine by this test, but each of them exhibits some peculiarity when treated in the same way, which would give a clew to its identity. A convenient reagent for the detection of alkaloids can be made by mixing a weak solution of potassium chlorate with enough strong hydrochloric acid to turn it bright yellow, and enough water to make it very pale yellow. This euchlorine solution is added by degrees to the solution of the alkaloid in HCl, which is boiled after each addition. Strychnine gives a fine red color, bleached by excess and returning when boiled. Brucine gives a violet color in the cold, which is bleached by excess and restored by boiling. Narcotine gives a brightyellow color in the cold, which becomes pink on boiling and adding more of the euchlorine solution. Quinine gives a faint yellowish pink on boiling. After cooling the solution weak ammonia is gradually added, when: Strychnine gives a yellow color unchanged by boiling. Brucine gives the same. Narcotine gives a dingy green, becoming brown on boiling. Quinine gives a bright green, becoming yellow on boiling. Morphine gives no reaction, but if, after boiling with the euchlorine solution, the liquid be cooled and allowed to remain in contact with zinc for a minute or two, it will give the characteristic pink reaction with ammonia.

William Crookes, observing the phosphorescence of alumina and its various forms under the influence of the electrical discharge in vacuo, has remarked the full red color which it presents. The spectrum of the glowing earth is marked by an intensely brilliant and sharp line, to which the color is due. Observations by M. de Boisbaudran led him to suppose that the presence of chromium is indispensable to the production of this color. Mr. Crookes having, in experiments directed expressly to this point, produced the red color with alumina freed from chromium, suggests four other possible explanations of the phenomenon: 1. The crimson line is due to alumina, but is capable of being suppressed by an accompanying earth which concentrates toward one end of the fractionations. 2. It is not due to alumina, but is due to an accompanying earth concentrating toward the other end of the fractionations. 3. It belongs to alumina, but its full development demands certain precautions to be observed in the time and intensity of ignition, degree of exhaustion, or its absolute freedom from alkaline and other bodies carried down by precipitated alumina; or, 4. The earth alumina is a compound molecule, one of the constituent molecules of which gives the crimson line. According to this hypothesis, alumina would be analogous to yttria.

Among the questions to which the Committee on Electrolysis of the British Association gave attention during the year, was whether the well-marked metallic alloy or quasi-com

pound could be in the slightest degree electrolyzed by an exceedingly intense current. Until all such bodies as were open to experiment had been cautiously and strenuously examined, they were unable to say whether there was a hard and fast line between the modes of conduction, or in what manner the graduation from one to the other occurred. Another important question was whether the electric current actually decomposed or tore asunder the molecules of the liquid through which it passed, or whether it found a certain number of those torn asunder or dissociated into their atoms by chemical, or at any rate, non-electrical, means, and that these loose and wandering atoms submitted to the guiding tendency of the electric slope, and joined one or the other of two processions toward either electrode, only offering resistance when brought into immediate proximity with the electrode.

Dr. Hans Molisch proposes as more delicate and speedy tests than have hitherto been used for distinguishing between animal and vegetable fibers, two new sugar reactions which he has discovered and described in full in the "Transactions of the Imperial Academy of Sciences in Vienna." They are, the production by all sugars with alpha naphthol of a deep-violet coloration, and with thymol of a cinnabar-ruby-carmine - red, flocculent precipitate. The same reactions are given indirectly by the carbohydrates and glucosides, from which sugar is formed after treatment with sulphuric acid. Plant-fibers contain sugar or the substances convertible into sugar, and give the sugar-tests; animal fibers do not. A few silks give a weak, transient reaction, but it is so slight and continues for so short a time that it need not deceive the careful observer. It is important, however, in applying the test, to remove all foreign vegetable matter that may be accidentally present, or left in the finishing. This may be done by boiling and washing.

Lecoq de Boisbaudran having asserted, contradictory to Becquerel's conclusions, that calcined alumina does not give a trace of fluorescence when submitted to the electric discharge in vacuo, and that the red fluorescence of alumina seems to depend upon the presence of chromium, Becquerel has repeated his experiments, using for the purpose substances furnished by De Boisbaudran himself, and finds his previous conclusions confirmed. The fragments of albumina, when excited by the light of the electric arc, emitted a red light, which, however, was much weaker than that given out, under the same circumstances, by alumina containing chromium. But, after calcination, this alumina became quite as luminous as alumina containing chromium, and of the same color. With alumina prepared by himself, the light emitted was the characteristic red light. The addition of chromium, then, does not change the color of the phosphorescent light, but simply increases its intensity. Becquerel calls attention to the difference in the luminous phe

nomena according as they are produced by the electric light in the phosphoroscope or by the electric discharge in vacuo; the former effects being simple, but not obtainable with all bodies. Crookes has also examined this subject, with a view of clearing up the discrepancies between the two observers. His results generally corroborate Becquerel's observations.

A. Percy Smith says, in a note on "The Identification of Alkaloids and other Crystalline Bodies by the Aid of the Microscope," that the number of cases in which such substances can be identified by this instrument alone is extremely limited; but, as a test of purity, microscopic investigation has a very wide application. When we are dealing with a substance that, when pure, crystallizes in a definite form from any particular solvent, it is manifest that any departure from that form would lead to the suspicion of adulteration. Again, if we take such a substance as bark or opium, it is quite possible to distinguish from one another the various alkaloids which it contains. Besides the form assumed by the free base, it is of importance to convert it into a salt, as there is frequently a marked departure in the form of the crystals of the latter from that of the base. Some experience is necessary in selecting the most suitable solvent from which to crystallize an alkaloid, as the duration of the evaporation may have a marked effect upon the form of the crystals. In some cases, evaporation may be accelerated by the aid of heat; in others, such a proceeding is fatal to success. The addition of alcohol to ether, and of water to alcohol, appears to be the best means of retarding the process when necessary. The author always employs polarized light by which to view the crystals, either with or without the addition of a selenite plate. Here, again, the duration of evaporation has a marked effect, as also does the strength of the solution. If the substance is deposited in a thin film, it may be altogether invisible without polarized light. Thick crystals frequently produce color without the selenite, and those that are very thick may depolarize without any coloration. This being borne in mind, no difficulty whatever is experienced in practice, as it is easy to compare with an alkaloid of known purity crystallized under the same conditions.

J. Edward Whitfield has reported upon the analysis of natural borates, in which, instead of the inaccurate methods hitherto in use, boric acid has been determined by a method devised by Dr. F. A. Gorch. The minerals analyzed are Colemanite, from California; Priceite, from Oregon; Ulexite, from Nevada; Ludwigite, from the Banate, Hungary; Datolite, from Bergen Hill, N. J.; Danburite, from New York; and Axinite, from Cornwall and from Dauphiny, France.

Atomic Weights.-Prof. Thorpe and Mr. A. P. Laurie have redetermined the atomic weight of gold from a preparation of the double bromide of potassium and gold. Taking Stas's

value for oxygen at 15.96, the atomic weight of gold is fixed by the average result of their analyses at 196-85; but if, with Mendelejeff, we consider oxygen 16, the atomic weight of gold becomes 197-28. Mendelejeff considered the old value of gold, 1962, to be too low, because there was no place in the periodic system for an element of that atomic weight having the properties of gold. Hence the result of the present determination has been to place gold in what seems to be its proper position in the periodic classification.

Gerhard Krüss has determined the atomic weight of gold by the analysis of neutral trichloride and of potassium gold bromide. The mean value derived from five methods was 196-669. The author regards 196 64 as most probably correct.

A. C. Cousins has observed, in studying the relations between gold, thallium, and mercury, that the atomic weight of mercury is the mean of those of gold and thallium; that its specific gravity in the liquid state is very nearly the mean of their atomic volumes; and that its own atomic volume is almost exactly the theoretical specific gravity of an alloy formed of equal weights of gold and thallium.

Prof. Carnelly, in a paper in the British Association on "The Antiseptic Properties of Metallic Salts in relation to their Chemical Composition," held that there was a relation between the atomic weights of various substances and their antiseptic properties, and suggested that there was a distinct relation between the power which these antiseptic bodies had upon animals and those which they produced upon micro-organisms.

Prof. Thorpe and Mr. J. W. Young have determined the atomic weight of silicon, from the tetra-bromide, which they prepared in considerable quantity, at 28.332.

Apparatus.-J. B. Mackintosh has devised an improved form of Elliott's gas-apparatus to obviate difficulties in the ordinary form of that apparatus, and prevent the liability of accidentally introducing some air during the operation. The essential feature of the apparatus is a three-way T-stopcock on the measuring burette, by which connection may be made between any two of the burettes to the complete isolation of the other. Another time-saving device is in the fixing of the zero-points of the graduations. In the measuring and explosion burettes the zero-point is taken at that point where the capillary-tube expands into the burette, and where the water will naturally remain when the excess drains to the bottom of the burette. This renders the adjustment to zero an automatic one, with no sacrifice of accuracy. The absorption-tube has a single gradation at 100cc.

A new form of spectroscope has been devised by G. Krüss, which is based upon the Bunsen and Kirchhoff instrument, but has received a number of modifications and additions adapted to make it available as a universal spectroscope.

With it, spectrum measurements may be made between two colors whose wave-lengths differ by only 0.000,000,000,015mm. The inventor thinks that the results obtained by this instrument when used as a spectro-photometer, are fully equal, if not superior, to those obtainable with polarizing instruments.

Charles W. Folkard has described a simple apparatus, made from ordinary laboratory ap pliances, for the bacteriological examination of water. Test-tubes, about 7 inches long and seven-eighths of an inch in diameter, are used to receive the nutrient jelly. They are closed by a plug of cotton-wool, which is tied by thread round a piece of glass tube bent at right angles and drawn off at one end. The bent tube has a capacity of 1cc., and serves for the introduction of the measured quantity of water for experiment. The whole is sterilized in the usual way. The water, of which a sample is to be examined, is allowed to run through a piece of three-eighths-inch India-rubber tube (pierced with a small hole in the middle, and furnished with a glass jet at the end) till all the germs on the tube have been washed away. The capillary end is passed through the hole in the India-rubber tube, and sufficient time is allowed for any germs on it to be washed off. The capillary end is then broken off by the fingers or by a pair of pliers, while it is inside the India-rubber tube. The water (which is of course running all the time) fills the bent tube, being assisted, if necessary, by partially stopping the glass jet for an instant. The bent tube is then withdrawn, the capillary end is sealed in the flame, and the lcc. of water is transferred to the test-tube by shaking.

Schall has constructed a balance on which the ratio of the density of any given gas to that of hydrogen-and hence the molecular weight of this gas-may be read directly from the deflection.

Agricultural Chemistry.-Sir J. Lawes and Dr. Gilbert, reporting in the British Association on "The Present State of the Question of the Sources of Nitrogen in Vegetation," quoted the opinions of a number of writers on the cultivation of the soil, and said that the results at present are extremely conflicting as to whether free nitrogen comes into play in any way. The results quantitatively are most discrepant, and the explanations are almost as numerous as the observers; still there are many results which can only be explained in one of two ways: either error was at work or free nitrogen was brought into operation. The authors thought, however, that they must hold their opinions in abeyance for the present. They dwelt upon the experiments which had been made in the raising of various crops, and said it was shown that nitrogen was derived from the residue of crops previously taken from the soil. There was clear evidence of nitrification of the subsoil in certain cases. The evidence was at present inadequate to justify a definite conclusion upon the matter.

Warrington's experiments at Rothamstead, before referred to in the "Annual Cyclopædia," indicated that in "our clay soils the nitrifying organism is not uniformly distributed much below nine inches from the surface." In later experiments, in which rather more soil was placed in the solution to be nitrified, and a proportion of gypsum was added, the results were in many respects entirely different. No failure to produce nitrification was observed in samples of soil down to and including a depth of two feet from the surface; and in some instances nitrification took place at as great depths as four and six feet, but at seven and eight feet all the experiments failed.

Miscellaneous-John Trowbridge and C. C. Hutchins have made new spectroscopic examinations to determine the question of the existence of oxygen in the sun's atmosphere, which is still a matter of doubt. Dr. Henry Draper was firmly persuaded from the apparent coincidences of lines of oxygen with certain bright spaces in his photographs of the sun's spectrum, that oxygen existed in the solar atmosphere; and his investigation was accepted by M. Faye. Prof. J. C. Draper also reasoned that oxygen existed in the sun from the coincidences of bright oxygen lines with dark oxygen lines in the spectrum. With the use of spectroscopes of much wider dispersion power than were at the command of these observers, and therefore giving more numerous and accurate data, the authors found that the "bright lines" of the sun's spectrum vanished at once, or no longer appeared as such, and all the apparent connections between them and the oxygen lines also disappeared. The hypothesis of Prof. J. C. Draper, that the dark lines occupying the bright bands of Dr. H. Draper's spectrum is rendered untenable by the lack of any systematic connection between the two.

Dr. Edward Schunk, President of the Chemical Section of the British Association, delineated the probable future of chemistry in his inaugural address. The question, he said, had frequently suggested itself to him, will chemical science go on expanding and developing during the next few generations, as it has done in the course of the last hundred years, or will there be limits to systematic chemistry-i. e., to the history and description of all possible combinations of the elements? He was inclined to take the latter view. He thought it probable that in the course of time, at the rate at which we are now progressing, nearly all possible compounds will have been prepared, all the most important chemical facts will have been discovered, and pure chemistry will be practically exhausted, and have arrived at the same condition as systematic botany and mineralogy, with only rarely a new plant or mineral to be determined, now are. But chemical science would not cease. It would continue to develop, but in other directions than those previously pursued. As the botanist has still a wide field of investigation in physiological

botany, so the chemist will find extensive opportunities for research in such investigations as those of the processes whereby the substances constituting the various organs of plants and their contents are formed, and those again to which the decomposition and decay of vegetable matter are due; subjects as to which our knowledge is quite elementary, but which, it seemed to him, admitted of an extension and development of which we have at present not the least conception. The very first steps of the process whereby organic or organized matter is formed in plants are hardly understood. Granted that we are able to trace the formation in a plant of a compound of simple constitution, such as oxalic or formic acid, how far would we still be from understanding the building up of such compounds as starch, albumen, or morphia? The syntheses so successfully and ingeniously carried out in our laboratories do not here assist us in the least. We know the steps by which alizarene is artificially produced from anthracene; but does any one suppose that the plant commences in the same way with anthracene, converting this into anthraquinine, and having acted on the latter first with acid, then with alkali, arrived at last at alizarene? Indeed, the plant never contains ready-formed alizarene at all. What we have observed from the beginning is a glucoside, a compound of alizarene and glucose, which, so far as we see, is not gradually built up, but springs into existence at once. With respect to the decomposition of organic and organized matters, the author was inclined to think that some of the younger chemists and physiologists of to-day might live to see the time when all the now mysterious and unaccountable processes going on in the organisms of plants and animals, including those of fermentation, will be found to occur in accordance with purely physical and chemical laws.

In a lecture on the rate of explosion in gases, delivered during the meeting of the British Association, Prof. Harold B. Dixon illustrated his subject by performing the experiment of filling a vessel full of hydrogen and allowing it to siphon itself out while the air penetrated into the vessel and mixed with the hydrogen. This experiment, the author said, exhibited the three divisions of gaseous explosions: the ordinary combustion; the vibratory movement, due, he believed, to the explosion of the air and hydrogen in unison with the mass of the gas in the tube; and the explosion of the whole mass. He believed there was some relation between what he might call the mean velocity of translation of the products of combustion and the bodies burned, which would be found to coincide with the actual rate of explosion. The study of explosions was of double interest-an interest attaching to the power which it offered in the hands of men, and a grander theoretical interest attaching to the play of the natural sources here shown in great intensity. In their ordinary questionings of nature we were ac