pose, and the bromide of silver, likewise specially prepared, for comparison. The mean of a series of eight experiments gave 112:31 as the atomic weight of the metal. This determination is regarded as bearing against the validity of the hypothesis of Prout, that all atomic weights are multiples of that of hydrogen.

NEW PROCESSES.-Mr. Alfred H. Allen has indicated some valuable simple tests for the presence of hydrocarbon oils as adulterations in animal and vegetable oils. The methods for the detection of these oils are based on the density of the sample, the lower flashing and boiling points, the fluorescent character of the oils produced from petroleum, bituminous shale, and rosin, and the incomplete saponification of the oil by alkalies. The taste of the oil and its odor on being heated are also useful indications. If undoubtedly fluorescent, an oil certainly contains a mixture of some hydrocarbon, but the converse is not strictly true, as the fluorescence of some varieties of mineral oil can be destroyed by chemical treatment, and in other cases fluorescence is wanting. The greater number of hydrocarbon oils employed for lubricating purposes are, however, strongly fluorescent, and the remainder usually become so on treatment with an equal measure of strong sulphuric acid. If strongly marked, the fluorescence of a hydrocarbon oil may be observed in presence of a very large proportion of fixed oil, but, if any doubt exist, the hydrocarbon oil may be isolated. The fluorescence may be seen by holding a test-tube filled with the oil in a vertical position in front of a window, when a bluish "bloom" will be perceived on looking at the sides of the tube from above. A glass rod dipped in the oil and laid on a table in front of the window so that the oily end shall be projected in the view against the dark background of the floor, or a piece of black marble or smoked glass rubbed with a streak of oil and held horizontally before a window, will make a very slight fluorescence, readily perceptible. Turbid oil should be filtered, to get out the minute particles that might, by reflection, give an appearance of fluorescence. Dilution with ether, to which a little mineral oil imparts a strong blue fluorescence, gives an excellent test. The hydrocarbon oil may be driven off by heating it if its boiling-point is comparatively low, but may be better removed and the quantity of it measured by saponifying it, and washing the solution of the soap with ether. The hydrocarbon may, in this case, be recovered pure by separating the ethereal layer and evaporating it at or below a steam-heat. A good alkaline preparation for this purpose can be made by dissolving caustic potash in methylated spirit. The washing with ether should be repeated several times. The etherprocess is, however, not applicable to spermaceti and the waxes, on account of the large quantities so small in the other fats that it need not be taken into account-of matter they contain that is not acted upon by the alkalies

but is dissolved by ether. The nature of the hydrocarbon oil may be determined after it has been isolated, by observing its density, taste, smell, behavior with acids, and other qualities.

Professor G. Lunge, of Zürich, has perfected and described a simple and inexpensive process for procuring pure naphthalen that will not discolor. Presuming that the discoloration of naphthalen is analogous to that of phenol, he sought to remove the agent which caused it by oxidation. For this purpose he added an oxidizing agent in the ordinary chemical washing of naphthalen, using manganese dioxide, with complete success. Other oxidizing agents might be substituted for manganese dioxide, but a cheaper one can hardly be obtained. Naphthalen prepared by this process has kept its pure white color much longer than the "chemically pure" naphthalen made by the secret process of the manufacturers.

A patent has been taken out by M. Closson, of Paris, for a cheap and expeditious method of obtaining magnesia from magnesium chloride. The crude lye of magnesium chloride is treated with burned dolomite, or magnesian limestone, when the chlorine of the lye combines with the lime of the dolomite, so that if the latter is pure a magnesia of from 98 to 99 per cent standard can be easily made on a large scale. The magnesia bricks prepared by this process at Leopoldshall resist even the flame of the oxyhydrogen-blast. The cost is fifteen shillings a ton. Sulphate of lime is obtained as a by-product of the process through the use of calcium chloride to remove the magnesium sulphate that is present in the magnesium chloride, and is used by paper-makers under the name of pearl-hardening. The value of the new process in its bearing on the manufacture of fire-proof furnace-linings, crucibles, etc., is very great.

Herr A. Wagner recommends the following process, which has proved very satisfactory for the limestone waters of Munich, for the determination of the organic matter in water. After the determination of all the other constituents of the water, he evaporates suitable quantities to dryness and separates the dry residue by means of distilled water into an insoluble and a soluble portion, the latter of which contains the chief bulk of the organic bodies. In the insoluble portion, which in the waters he has to deal with consists almost entirely of calcium and magnesium carbonates, he determines the organic matter by igniting a dried specimen in a platinum crucible and treating subsequently with ammonium carbonate in the customary manner. The portion soluble in water, if nitrates are absent or are present only in a quantity too small to be determined, is dried after evaporation in a platinum capsule, weighed, heated to a very low redness, and weighed again. If nitrates are present in larger quantities, so that the existing organic matter would not suffice to con

vert the nitrates into carbonates, he adds to the soluble portion, after drying and weighing, a little pure solution of sugar, evaporates to dryness, and heats the platinum capsule gradually and by piecemeal with a very small gasflame, so that no deflagration may happen. After prolonged but very gentle ignition, the sugar-charcoal is found burned away, when the residue is moistened with water containing carbonic acid, and weighed again after drying. The loss of weight in this case expresses the weight of the organic substances and the difference between the equivalent of the nitric acid which was present and of the carbonic acid which has taken its place. This difference can be easily calculated from the quantity of the nitrates as previously ascertained, and must be deducted. This process is not absolutely accurate, but Herr Wagner considers it more certain than others. Herr Wagner calls attention to the necessity, in experiments for determining the solid residues, of protecting the platinum or porcelain capsule in which the water is treated against the accumulation of a deposit from the gas-flame, through which a liability to error in weight is incurred. For this purpose he uses a thin sheet of platinum, instead of the ordinary wire gauze, between the capsule and the flame.

Mr. Thomas Moore has published the following new process for the separation of nickel and cobalt from iron: Having removed any excess of free acid by evaporation, and dissolving the residue in water, add to the solution a sufficient quantity of ammonic sulphate to form a double sulphate with the nickel and cobalt present. Dilute to about 150 c. c., and add a rather large excess of oxalic acid, and stir well. In case a precipitate form, more ammonic sulphate should be added until a clear solution is obtained. Add ammonic hydroxide in considerable excess; stir, heat gently for a few minutes, and filter; wash well with water containing ammonia; or dilute to about 500 c. c., and, after allowing the precipitate to settle, withdraw a given portion of the clear upper stratum of liquid. This, after a further addition of ammonic sulphate, to lessen the resistance to the electric current, is ready for electrolysis or any other method of estimating the nickel or cobalt.

Messrs. R. H. Chittenden and H. H. Donaldson, of the Sheffield Laboratory, Yale College, describe a process for the detection and determination of arsenic in organic bodies, which they recommend as very accurate, delicate, and simple. It is based upon Gauthier's process, and somewhat resembles it, but requires for reagents only nitric acid, sulphuric acid, and zinc. The organic matter is destroyed by successive oxidations with nitric and sulphuric acids, as in Gauthier's method, but at a much lower temperature. The suspected matter is then treated for fifteen minutes at 200° C., and allowed to cool, when a hard, carbonaceous residue, free from nitric acid, and containing

the arsenic as arsenious acid, is formed. This is extracted with water till it has been made to give up its arsenic, and the reddish-brown fluid containing some organic matter is evaporated to dryness. The residue is dissolved at a gentle heat with a definite quantity of dilute sulphuric acid, and introduced to a Marsh's apparatus for the decomposition of arseniuretted hydrogen by artificial heat, to which a Bunsen wash-bottle and a device for graduating the admission of the fluid have been added. The resultant gas having been dried in a chloride of calcium tube, is passed through a red-hot glass tube. Not a trace of arsenic passes by if the cooled tube is of proper length. The apparatus is then filled with hydrogen generated by the sulphuric acid-zinc process, and the glass tube, having been heated to redness, the arsenical solution in concentrated form is mixed with sulphuric acid, and the mixture is slowly passed into a separating funnel; then more and stronger acid is added, and the heat is kept up till the decomposition is wholly effected. The arsenic being collected in the form of a mirror of metal, the tube is cut, at a safe distance from the mirror, and weighed. The arsenic is removed by heating, and the tube is weighed again, when the difference gives the amount of metallic arsenic. The method is capable of detecting as little as the one thousandth of a milligramme of the metal. In organic matters the experimenters have detected a millionth of a gramme in urine and in an extract from beef. The experiments are claimed to show that the presence of organic matter in considerable quantity does not interfere with the recovery of the entire amount of arsenic.

VEGETABLE ANALYSIS.-Professor Henry B. Parsons, of Washington, D. C., has described a method for the more accurate analysis of plants. His apparatus includes a worm of block-tin pipe, suitably connected with a glass percolator, within which is suspended a smaller tube, having a bottom of filtering-paper and fine, washed linen. The weighed sample of the finely-powdered herb is placed within this tube for extraction. The solvent is introduced in a glass flask, tightly fitted to the outer percolator, and is volatilized by the application of heat through a water-bath. A tared filter, prepared by allowing fine asbestus, held in water, to settle on the perforated bottom of a platinum crucible, is also provided and connected with the receiving-vessel, while this in turn is connected with a Bunsen's pump. The air-dried specimen of the plant to be analyzed should be ground or beaten till all the particles will pass through a sieve having from forty to sixty meshes to the linear inch. A part of this should be further pulverized till it will pass through a sieve having from eighty to one hundred meshes to the linear inch. The finer part of the sample is employed in the immediate analysis, while the coarser part is reserved for the separation of those proximate principles

which may seem, from the analysis, to be worthy of more extended investigation. The amount of moisture is estimated by ascertaining the loss of weight on drying a small portion of the sample. The crude ash left after ignition is separable into the constituents that are soluble in water; those that are insoluble in water, but are soluble in dilute hydrochloric acid; and those which, insoluble in those substances, are soluble in sodic hydrate. The residue still undissolved consists usually of a little unconsumed carbon. The amount of nitrogen is determined by combustion with excess of soda-lime. Exposure of a part of the sample to the action of pure coal-tar benzole gives the benzole extract, which may consist of volatile oil removable by evaporation; alkaloids, glucosides, and organic acids, soluble in water; alkaloids, and possibly glucosides, soluble in dilute acids; chlorophyl and resins, soluble in 80 per cent alcohol; and wax, fats, and fixed oils which do not yield to either of the solvents. The part of the plant not dissolved by benzole is further treated with absolute alcohol, and afterward with other agents, as water, subacetate of lead, and dilute hydrochloric acid, as special tests. The part which remains insoluble, after treatment in alcohol, is exposed to the action of water; that part still remaining insoluble is boiled in concentrated sulphuric acid, for the conversion of starch, etc., into dextro-glucose. Boiling the residue from this treatment with sodic hydrate gives an extract containing albuminous matter, modifications of pectic acid, Fremy's "cutose," coloring, humus, and decomposition products. The crude fiber from this process, treated with chlorinated soda, bleached, and dried, leaves a residue of cellulose. Treatment with benzole, 80 per cent alcohol, and water, removes from nearly all plants the constituents of greatest chemical and medicinal interest. In analyses of food materials the compounds extracted by dilute acids and alkalies have great value.

A NEW DIGESTIVE AGENT.-In a paper before the French Academy of Sciences, M. Wurtz has drawn attention to the great chemical and therapeutical value of a substance called papaine, which possesses the property of exciting the digestive function. It is derived from the juice of the common papaw-tree (Carica papaya), which belongs to the family of the Cucurbitacea, or gourds. The milky juice which contains the papaine is slightly bitter and styptic, free from tartness, but with a weak acid reaction, and is so highly charged with albumen that Vauquelin compared it to blood deprived of its coloring matter. It flows from incisions made in the bark and the green fruits, and is immediately bottled and sent to market, either pure or with the addition of ten or twelve per cent of alcohol to prevent fermentation. If pure, it becomes coagulated; if mixed with alcohol, it remains liquid, and, after standing, separates into a clear liquid and a white precipitate, composed in great part of albumen,

fibrine, and a considerable quantity of precipitated papaine. Alcohol precipitates from it crude papaine; this, after being washed in alcohol and ether, to remove fatty matters, is again dissolved in water. The precipitate from this solution is pure papaine, which, when purified by dialysis, has the composition of an albuminoid substance. Papaine, refined with the subacetate of lead, offers several distinctive characteristics, among which are: 1. It is very soluble in water, dissolving like a gum; 2. The solution makes a lather with water; 3. The solution becomes turbid in boiling, without coagulating; when it is curdy it sometimes leaves an insoluble residue in water; left to stand, the solution becomes turbid after some days, and a microscopic examination shows it to be filled with vibriones; 4. In the presence of a saccharine liquid, papaine acts as an alcoholic ferment with an extraordinary energy and promptitude, but the digestive property may be arrested by the application of benzoic or salicylic acid. The most important property of papaine, and one which puts it in the rank of the most powerful digestive ferments, is its action on meats. One part of papaine will digest and transform into soluble peptone from two hundred and fifty to three hundred parts of meat. Its solubility in different fluids allows it to be used in a great many pharmaceutical forms; and, being a vegetable juice, it can be preserved with more stability than animal ferments, and can be kept indefinitely when dry.

REPORT ON PHOTOMETRIC STANDARDS.-The committee appointed by the British Board of Trade to examine and report upon the different standards of photometric measurement which have been proposed for adoption, as well as upon the standard now used for testing the illuminating power of coal-gas, have made a report recommending the standard air-gas flame of Mr. G. Vernon Harcourt as the most exact and trustworthy. This flame is produced by burning a mixture of air with that portion of American petroleum which, after repeated rectifications, distills at a temperature of 50° C. or 122° Fahr. The portion is almost entirely composed of pentane, and is used in the proportion of one volume of pentane at 60° Fahr. to 576 volumes of air. The flame is brought to a height of two and a half inches with a burner a quarter of an inch in diameter. The light is quite uniform, the extreme difference obtained by two observers in nineteen observations being 0.3 of a candle, or 1.8 per cent. The committee found candles very objectionable as standards, and subject to a maximum variation in 115 determinations of 22.7 per cent between two pairs of candles. Messrs. Keates and Sugg's plan for burning sperm-oil with a two-inch flame from a circular wick was found subject to sudden variations; and Mr. Methven's system of allowing only a particular part of a three-inch coal-gas flame to pass to the photometer was not considered sufficiently exact for the work required of it.

COLOROMETRIC ESTIMATION OF CARBON IN IRON.-The great extension which has taken place in the applications of steel has made it desirable to obtain tests for the presence of carbon of a more minute degree of exactness than has heretofore been deemed sufficient. Professor Eggertz has described, in the "Jern Kontorets Annalen," a method of colorometric estimation which is applicable to cases in which an exactness of 0.01 per cent is wanted. The basis of his process is the solution of ferric hydrate in nitric acid, to which a volume of water equal to that of the acid is added; when the quantity of acid used is commensurate with the proportion of carbon in the iron, the yellowgreen color of the solution is cleared on adding an equal volume of water. Care must be taken that no chlorine is present, for the slightest trace of that substance gives a yellowish tint. The quantity of nitric acid required for solution is regulated to a certain degree by the supposed amount of carbon in the iron. For a solution with a lower amount of carbon than 0.25 per cent, 2·5 c. c. of nitric acid should be used for 0.1 gramme of iron; with carbon of 0-3 per cent, 3 c. c.; with carbon of 0.5 per cent, 35 c. c.; and for carbon of 0.8 per cent, 4 c. c. of acid. When the amount of carbon is altogether unknown, begin with 2.5 c. c. of nitric acid, and afterward add more as soon as the color of the solution or the amount of separated carbon shows that more acid is required. Too little acid gives too deep a shade, while excess of acid may be remedied by adding more water. The iron to be tested should be finely divided by filing, boring, planing, or crushing. The solution should be made at 80° C., with shaking of the tube. It is often more convenient to put the tube in boiling water; and speed can be gained at the expense of having a reddish-yellow film to deal with, by gently boiling the mixture. Special normal solutions, for comparison, are prepared in the same manner and graduated by successive dilutions from the normal, which represents 0-10 per cent of carbon per c. c. of 0.1 gramme of iron, and may be used for iron with 0.8 per cent and higher of carbon, down to the normal which represents 0.005 per cent of carbon, and is used for iron with from 0·04 to 0·08 per cent, or the lowest amount of carbon found. The distribution of the light in the room should be considered in applying the test, and it should be observed that a tube held on the right is generally a little weaker in color than one held on the left. The presence of manganese in the iron communicates a brown color, which is changed by heating to 100° C. to a weak redviolet; chromium gives a grayish blue; vanadium, a weak yellow; nickel, a green-all of which colors vanish under a greater or less dilution with water. Cobalt gives a red color which can not be regarded as absent till the dilution has extended to 40 c. c. Phosphorus, sulphur, copper, silicon, in the proportions in which they were tested by Pro

VOL. XXL-7 A

fessor Eggertz, did not perceptibly affect the color.

A NEW VEGetable ColoRING PRINCIPLE.— Messrs. S. P. Sadtler and W. L. Rowland have analyzed a new vegetable coloring matter found in the West-African wood called betha-barra, a wood which is much valued for its extreme toughness and its capability of receiving a high polish. The wood is compact, very heavy, and of nearly the color of black-walnut. On close examination the interstices of the fibers are seen to be filled with a yellow, crystalline powder. In this respect the beth-abarra differs from logwood, barwood, camwood, and red sandal-wood, with which it was compared, in which the color is uniformly disseminated, and the fiber appears as if it had been soaked in a solution of corresponding color. The solution of the coloring matter obtained by extracting from the sawdust or raspings was treated for precipitation with acetic acid, and the pure substance was obtained by successive crystallizations from the alcoholic solution of the precipitate. The material thus gotten is a tasteless, yellow compound, apparently crystallizing in scales and needles, which are found under the microscope to be made up of a series of flat prisms, joined laterally. The crystals are unchanged in dry or moist air, insoluble in cold water, very slightly soluble in hot water, but readily soluble in alcohol and ether; they dissolve with a deep claret-red color in the presence of even a trace of alkali or alkaline carbonate, and melt at 135° C. Analysis gives a composition for the material dried at 125° C. which is represented by the formula C28H2O5, or possibly C22H23O4, and for that dried at 100° C., C28 H2O+3H2O. The beth-a-barra presents a similarity in many of its reactions leading to the suspicion of a relationship with chrysophanic acid and chrysarobin.

ACTION OF SEA-WATER ON CAST-IRON.-Professor A. Liversidge, of the University of Sydney, has made a study of the action of sea-water on cast-iron in the case of the screw of the steamdredge Hunter, which became so rotten that it had to be removed. Even on the most cursory examination the specimen was seen to differ entirely from the original cast-iron, except in its shape, which remained unchanged. The material was so altered in composition that it might be safely described as a pseudomorph, since it was almost entirely made up of oxide of iron and particles of graphite. It was quite sectile, being readily cut with a knife. The powder under the microscope presented a mixture of brilliant scales of graphite with browncolored oxide of iron and a few widely scattered minute particles of metallic iron. The external part of the specimen was of a dull-gray color, while within it was rusty brown, with dark bands following more or less closely the outer contour lines. The specific gravity was found to be only 1.63. Phosphorus appeared to have been completely eliminated by the

action which had gone on, and the amount of sulphur was quite small. Several notices of a similar transformation of cast-iron into graphite occur in the annals of chemistry, the oldest one dating as far back as 1740. Wrought or malleable iron does not appear to be subject to it. The plumbaginous masses thus formed frequently but not invariably become red hot and spontaneously inflammable on exposure to the air. The transformation is attributable to the local galvanic action set up between the diffused scales of graphite, films of slag, or other foreign matter contained in the iron. The coating of plumbago and rust is negative to the metal, and hence if left on assists in further corrosion; but the rate of corrosion, according to the observations of Mr. Robert Mallet, appears as a decreasing one when the coating first formed is removed prior to a second immersion. When cast-iron is exposed to the combined action of fresh water and seawater, the action is said to be much more rapid, for the heavier sea-water below, and the lighter fresh water above, with the iron, form a voltaic pile having two liquids and one solid.

A NEW MINERAL, BEEGERITE.-Mr. George A. König has described and analyzed a new mineral from the Baltic lode of the Geneva Mining Company, Park County, Colorado, to which he has given the name of beegerite. The specimen on which the investigation was made was composed of quartz, about one half, and the new mineral in the two conditions of a light gray mass, and of crystals showing a darker gray color but exhibiting a very strong metallic luster, which were chemically identical with the gray mass. Beegerite forms minute crystals of orthorhombic habit; has a specific gravity of 7.273; acts before the blowpipe like a mixture of galenite and bismuthite, with a small quantity of copper, and decrepitates; and is dissolved by concentrated hydrochloric acid, slowly in the cold, but rapidly in the heated acid. The analyses gave it a composition represented by the formula, Pb. Bi2 S = 6 PbS+ Bi2S, with some copper. The compound exhibits properties nearly coinciding with those of galenite, and is qualitatively related with the two species, cosalite and schirmerite.

THE ALKALOID OF PITURIE.-Professor Liversidge, of Sydney, New South Wales, has extracted the alkaloid principle of piturie, a vegetable substance obtained from a species of Duboisia, of the order Solanaceae, which is chewed by the Australian natives, and exerts an action similar to that of tobacco. Baron von Mueller and M. A. Ladenburg had previously experimented with the alkaloid, but their accounts of it do not agree. As prepared by Professor Liversidge, by distillation of the plant with caustic soda, solution in ether, and removal of the ether by distillation, the alkaloid, piturine, is at first clear and colorless, but becomes yellow and finally brown with access

of air, especially when exposed to sunlight. If air is excluded it will remain unchanged for a long time. It is soluble in all proportions in water, alcohol, and ether, yielding colorless solutions, and produces a greasy stain on paper, which disappears after a time. It is a little heavier than water, is volatile at ordinary temperatures, giving a vapor which forms a dense fog with hydrochloric acid, irritates the mucous membranes very much, and induces violent headaches in those working with it. Its taste is acid and pungent, and very persistent; its smell when fresh is very like that of nicotine, but after it has become darkened is more like that of pyridine. It neutralizes acids completely. Its composition is represented by the formula C.H.N...

CULTIVATION OF NITRIC FERMENTS.—Mr. R. Warington has communicated some preliminary results of a course of experiments he has been making on the conditions in fermentation which respectively determine the formation of nitric and nitrous acid. When a small quantity of fresh soil is employed to seed solutions of chloride of ammonium supplied with nutritive ingredients, a pure, or nearly pure, nitric fermentation is obtained if the solution is sufficiently shallow and dilute, and the temperature low. Under such circumstances only a trace of nitrous acid is formed, and this changes into nitric acid before the conclusion of the action. If the solutions employed are much more concentrated, or the temperature is considerably raised, large quantities of nitrous acid are produced. In all cases in which soil has been used as seed, the nitrous acid exists only temporarily in the solution, the final product of the fermentation being always nitric acid. Soil added to a solution of nitrite of potassium, supplied with nutritive ingredients, readily converts the nitrite into nitrate. When solutions which have been seeded with soil and have undergone the nitric fermentation are themselves employed as seed for new solutions of ammonia, the final result as before is nitric acid, provided the solution used as seed is only a few months old. With older solutions the result of the fermentation is apparently only nitrous acid, which does not further change into nitric acid, except when, as sometimes occurs, a white organism, a bacterium, after a considerable time, appears on the surface of the liquid, and spreads, under favorable circumstances, to cover it. When a solution which has undergone the nitrous fermentation is used as seed, it again produces a purely nitrous fermentation. These results accord with the fact noticed by Pasteur, that the energy of infectious organisms may be reduced by cultivation. The nitrifying ferment appears, then, to exist in the three conditions of the nitric ferment of the soil, producing nitrates; the altered ferment producing nitrites; and the surface organism, which changes nitrites into nitrates.

RELATIONS OF BACTERIA AND VARIOUS GASES. -Mr. F. Hatton has made some experiments to