a

first by agitation with water, and then rendered perfectly neutral by means of a dilute solution of soda. Should it contain any unconverted benzol, this may be distilled off by means of steam. On the Continent, manufacturers do not appear to have succeeded well in manufacturing nitrobenzol; when it first became commercial article, their difficulty appears to have arisen from the fact that they experimented in earthenware vessels, which are both dangerous and unsuitable, and it was not until information was obtained from England, I believe, that they were able to produce this body at a moderate price.

We will now pass on to the processes for converting nitrobenzol into aniline. I have already mentioned that Zinin was the first who discovered that nitrobenzol could be converted into aniline, or, as he termed it, benzidam. His process consisted in treating an alcoholic solution of nitrobenzol with ammonia and sulphuretted hydrogen; but, although the discovery of this process was one of great importance from many points of view, still it was very tedious. Bechamp, however, found that by employing a mixture of acetic acid and finely divided iron instead of ammonia and sulphuretted hydrogen, the nitrobenzol was very rapidly converted into aniline, and this process has been found the best yet proposed for manufacturing aniline in large quantities. Many other reagents have been suggested, as arsenite of sodium, powdered zinc, &c., but none of them have been found so advantageous as iron and acetic acid.

In carrying out Bechamp's process, cylinders like those used for nitrobenzol (Fig. 1) were originally employed. The cylinder was set in brickwork, and heated by means of a small furnace, iron borings were first introduced, and

One neck was con

the door fixed in its place air-tight. nected to the upper extremity of a cast-iron worm by means of a pipe called an adapter; the second neck being fitted with a syphon-tube, for the introduction of the nitrobenzol and acetic acid. In working on the large scale it is necessary to add the nitrobenzol and acetic acid in small quantities at a time, otherwise the reaction is so violent as to almost burst the apparatus: by working carefully, however, there is no need to fear any difficulties, especially if the stirrer is well used. By the time all the charge has been introduced, a quantity of fluid will have distilled over; this is returned into the cylinder and the fire lit, and the aniline distilled off.

The principal change which has taken place in this process consists in using high pressure or superhcated steam for the distillation instead of fire, and working the apparatus by means of a steam-engine instead of by hand. In Fig. 4 is shown a sketch of the apparatus now generally employed for the preparation of aniline.

You will observe that the stirrer, which is worked by bevel wheels, has a hollow shaft or spindle, a, as seen in the section. This is ground to an elbow, b, connected to the steam main, c, and held down by a screw, so that when the steam is turned on, it passes through the hollow elbow down the shaft, and then blows out at the bottom, d, among the products; and in this manner the aniline is volatilised, and passes with the steam through the neck, e, and is condensed by a worm, not shown in this drawing. Aniline thus obtained is generally redistilled, and sometimes with a little lime or caustic soda, for the purpose of decomposing a body called acetanilide, which is often produced in the manufacture of aniline,

32

especially if the operation is conducted over a fire instead of with steam.

Commercial aniline generally appears of a pale sherry colour; when chemically pure, it is colourless, but if kept long it becomes quite brown. It possesses a peculiar odour, which is slightly vinous when the aniline is pure. It burns with a smoky flame, but is not very inflammable; its boiling-point is 182° C. One of its most characteristic reactions is its power of producing a blue or blue-violet colouration with chloride of lime, to which I shall again have occasion to refer. Aniline differs entirely from benzol and nitrobenzol, being perfectly soluble in dilute acids. This is owing to its being an organic base, and forming compounds with acids. Thus, with hydrochloric acid, it forms hydrochlorate of aniline; with sulphuric acid, sulphate of aniline, &c.

We will now, in a very rapid and general way, glance at the chemical changes which take place in connecting benzol with nitrobenzol and aniline.

Benzol, as I have already stated, is a hydrocarbon, i.e., a body composed of hydrogen and carbon only; it is represented by C6H6. This is treated with nitric acid, which contains HNO3.

The nitric acts upon the benzol and introduces its nitrogen and part of its oxygen, at the same time removing hydrogen and forming water.

Having now seen the various operations which require to be performed for the production of aniline from coaltar, we are prepared for the consideration of its coloured derivatives. We will, therefore, commence at once with the first of the coal-tar colours, "the mauve dye." I have already given you the history of its discovery; I will now tell you how it is made.

First of all aniline and sulphuric acid, in the proper proportions for the formation of sulphate of aniline, are mixed in a large vat with water, and boiled until perfectly dissolved. Bichromate of potassium is then dissolved in a second large vat. These two solutions, when cold, are mixed in a third and still larger vessel, and allowed to stand one or two days. In this way a large quantity of a fine black precipitate is formed; this is collected upon shallow filters, well washed with water, and then dried. When dry it is a most unpromising sooty-black powder, and contains various products besides the mauve; the most troublesome of these is a brown, resinous product, soluble in most of the solvents of the colouring matter itself.

At first this resinous substance was removed by digestion with coal-tar naphtha previously to the extraction of the colouring matter, which was afterwards effected with methylated spirits of wine, and the solution thus obtained when distilled left the mauve as a fusible bronzecoloured mass.

When digesting the black precipitate with naphtha or strong spirits of wine, the operation had to be performed in closed vessels under pressure or in connection with a condensing arrangement, otherwise large quantities of these valuable solvents would have been lost; and great difficulty was experienced in getting apparatus perfectly tight, on account of the "searching" character of these fluids. Substitutes had also to be found for the ordinary

materials employed by engineers for making good manhole joints, and a number of other matters which are apparently of but small importance, but it is remarkable the amount of difficulty and annoyance they caused. The method of extraction has, however, been materially improved upon by substituting dilute methylated spirits of wine for strong, as this weaker spirit dissolves only a small quantity of resinous matter but all the colouring matter, so that the digestion with coal-tar naphtha is now found unnecessary.

The solution of the colouring matter in dilute spirit is placed in a still and the spirit distilled off, the colouring matter remaining behind in aqueous solution; this is filtered and then precipitated with caustic soda. It is afterwards collected on a filter, washed with water, and drained until of a thick pasty consistence, and, if necessary, dried.

The solid mauve dissolves very freely in spirits of wine, forming an intensely coloured solution; it is also soluble to a small extent in water, but the aqueous solution on cooling forms a kind of jelly.

The formation of the mauve or aniline purple by the action of bichromate of potassium upon sulphate of aniline is a process of oxidation, and since the publication of the original specification at the Patent Office a great number of patents have been taken out for the preparation of this colouring matter, in which the bichromate has been replaced by other oxidising agents, as peroxide of lead, permanganate of potassium, peroxide of manganese, chloride of lime, ferrocyanide of potassium, chloride of copper, &c.; but I need not make any special remarks upon these various processes, as experience has shown that bichromate of potassium and a salt of aniline, the reagents first proposed, possess advantages over all others, and are now nearly universally employed for the preparation of aniline purple. The next best process appears to be that of Dale and Caro, in which chloride of copper is employed.

The affinity of aniline purple for silk or wool is very remarkable; and, if I take some wool, and pass it through a solution of mauve, you will see how rapidly it absorbs it, even from a very dilute solution. Aniline purple is sent into the market in three different conditions-in paste, in solution, and in crystals; but the latter are very rarely employed, as they are very expensive, and do not offer corresponding advantages to the consumer.

The mauve is the most permanent coal-tar purple known, especially with respect to its power of resisting the action of light.

I will now endeavour to give you some idea of the approximate amount of the various products we have considered obtainable from 100 lbs. of coal; and, for this purpose, I have arranged them in the following table, with their respective weights :

Coal..
Coal-tar..
Coal-tar naphtha
Benzol
Nitrobenzol
Aniline

Mauve

Lbs. Ozs. 100 O

You see the smallness of the amount of colouring. matter obtainable from coal or coal-tar; but there is fortunately one thing which to some extent compensates for this, and that is the wonderful intensity of this colouring-matter. I will illustrate this remarkable fact. I have here a large carboy, containing 9 gallons of water, and will now add to this a solution containing 1 grain of mauve, and illuminate the liquid with the magnesiumlamp; and you see the single grain has coloured this large bulk of water. A gallon of water contains 70,000 grains; therefore 9 gallons contain 630,000 grains. This solution, then, contains only 1 part of mauve to 630,000 of water. I have now shown you the manifold operations which have to be performed before we can derive the mauve

from coal-tar, and have also mentioned a few of the obstacles which had to be overcome before its manufacture on the large scale could be accomplished. We have thus laid the ground-work of our subject; and, in our next lecture, I hope to tell you a little more about mauve, and then give an account of the many other colouring-matters of which it may be considered the parent. (To be continued.)

NOTICES OF BOOKS.

Report on the Quality of the Kerosene Oil sold in the Metropolitan District (New York). By C. F. CHANDLER, Ph.D., &c., New York: D. Appleton and Co. 1870.

THIS paper is a report made by the author in his capacity of Chemist to the New York Board of Health, by which he was instructed to investigate the quality of the Kerosene sold in the city and neighbourhood of New York. The author treats of the composition and varieties of petroleum, on the refining of that liquid, on the quality of kerosene oil, and on the processes vaunted for rendering benzine non-explosive, all of which are perfectly worthless; and, next, enters into the details of the investigation of seventy-eight samples of kerosene oil obtained from the same number of retail dealers. Not one of these samples is safe; all samples contained benzine, gasoline, and naphtha to more or less extent; and only one sample (No. 79), also obtained from a retail dealer, was free from these admixtures, and contained only pure burning oil, usually known in this country as paraffin or crystal oil. The reporter next relates a series of experiments made with the view of ascertaining to what temperature the burning oils become heated in the reservoirs of the lamps in which they are used, different kinds of lamps being employed for this purpose. From these experiments we learn that, even while burning for seven hours, the temperature of the oil does not rise to above 90° F., and that, therefore, an oil which does not evolve an explosive vapour below 100°, and does not take fire itself below 110°, is perfectly safe.

The author next touches the subject of legislation on this matter, first quoting, from the British Acts of Parliament, the directions for applying the flashing test to samples of petroleum oil, and afterwards alluding to the Bill before the State Senate of New York, and discussing some points of interest to the inhabitants of that state. Very properly, the author reflects upon the bill as simply to be made applicable to New York and Brooklyn; it is not only against general good policy, but is a downright in fringement of a fundamental constitutional principle, to legislate only for a portion of the inhabitants of a state, or even to make so-called Permissive Acts. These are simply a remnant of feudalism which made slaves and serfs of the bulk of the people, inhabiting the same country, and acknowledging the same person as sovereign.

CORRESPONDENCE.

LOSS OF SODIUM IN SODA-WORKS.

To the Editor of the Chemical News. SIR,-In the "Chemical Notices from Foreign Sources" given in the CHEMICAL NEWS (vol. xxii., p. 21) appears a brief abstract of the results obtained by M. A. ScheurerKestner on the" Loss of Sodium Resulting from its Manufacture according to Le Blanc's Process." The results arrived at by this chemist (viz., that the formation of in

London Institution.-Our readers will be glad to hear General Superintendent of the above-named institution. that Mr. J. C. Brough has been appointed Librarian and

Utility of Lightning Conductors.-The Moniteur Belge of the 6th inst. contains the following:-The powder magazine Santo-Spirito, at Venice, containing no less than 300,000 kilos. (fully 300 tons) of gunpowder, was struck by lightning the other day. The electric discharge fortunately fell on the lightning conductor, the platinum point of which was molten and the rod split and twisted, but no other damage was sustained. The quantity of powder present, if exploded, would go far to lay in ruins ten cities of the size of Venice.

Quality of the Gas Supplied to the Metropolis.Dr. Letheby, the Chief Gas Examiner for the Metropolis, has recently reported to the Corporation and to the Metropolitan Board of Works on the quality of the gas supplied to the Metropolis by the Chartered, the Great Central, and the City of London Gas Companies. The average illuminating power of the gas, when burnt at the rate of five cubic feet per hour from Sugg's improved Argand burner has been as follows:-The common gas of the City Company has been equal to 17:55 standard sperm candles; that of the Chartered Company, at Leadenhall Street, has been 17:44 candles, at Gray's Inn Lane, 16:92 candles, at Arundell Street, Haymarket, 17:14 candles; and that of the Great Central Company, 17.82 candles. The illuminating power of the Cannel gas of the Chartered Company has been 24'44 candles, and of the City Company 28 candles. As regards impurity, Dr. Letheby reports that the gas of all the companies has been constantly free from sulphuretted hydrogen, although the amount of sulphur in other form than the last named, has varied considerably; for while it amounted to an average of only 12:29 grains per 100 cubic feet of the Great Central gas, and 1271 grains per 100 feet of the Cannel gas from the City Works, it reached to 22 13 grains, 22:39 grains, and 29.65 grains in the gas of the Chartered Company at the three testing stations of Leadenhall Street, Gray's Inn Lane, and Arundell Street. In connection with this important part of the subject, Dr. Letheby reports that the testing of the gas of the several companies for sulphur during the last twelve months has shown how this obnoxious impurity may be influenced by different methods of purification; for in the case of common gas, the

34

average proportion of sulphur in the gas from the Great Central Works has only been 12.91 grains per 100 cubic feet, whereas in the gas of the Chartered Company it has ranged from 2141 grains to 28.59 grains per 100 cubic feet-the average for all the stations of that company being 24'77 grains, and of the City Company 19.75 grains. And again, although the average amount of sulphur in the Cannel gas of the City Company has been but 10 29 grains per 100 cubic feet, it has reached to an average of 24:48 grains in that of the Chartered Company. These large differences are, according to Dr. Letheby, entirely owing to the different methods of purification, and he directs attention to it as a matter of great practical importance. The other impurity, ammonia, has been always absent from the common and the Cannel gas of the City Company, but it has been frequently present in the gas of the other companies, averaging 0.38 of a grain per 100 cubic feet of the Great Central gas, and from 187 to 3.68 grains in that of the gas from the different stations of the Chartered Company; in fact, it has exceeded the prescribed amount of 5 grains per 100 cubic feet, on seven occasions in the Chartered gas at Leadenhall Street, and on nine occasions in the same company's gas at Gray's Inn Lane.

CHEMICAL NOTICES FROM FOREIGN SOURCES.

Under this heading will be found an encyclopædic list of chemical papers published abroad during the past week, with abstracts of all susceptible of advantageous abridgment. The two halfyearly volumes of the CHEMICAL NEWS, with their copious indices, will, therefore, be equivalent to an English edition of the "Jahresberichte."

NOTE. All degrees of temperature are Centigrade, unless otherwise expressed.

Comptes Rendus des Séances de l'Académie des Sciences, July 4, 1870.

This number opens with a report on the

Pyramids of Villejuif and Juvisy.-M. Delaunay.-In the year 1670, M. Picard took, as basis of his geodesical triangulations, the nearly straight roadway which joins together the communes of Villejuif and Juvisy, a distance of 5748 toises (1 toise is equal to 6 feet 6 inches English measure). This basis having been verified in 1740, by J. Cassini and A. La Caille, they erected there, at the expense of an old scientific institution, re-modelled afterwards into the Academy of Sciences, two pyramids, which, having become out of repair, have now been restored, and on each is placed a black marble slab, containing, in gilt letters, simply the following inscription (translated):"Pyramid of Villejuif; northern limit of the geodesical basis of Villejuif to Juvisy. 1670-Picard. 1740-J. Cassini and La Caille. Property of the Academy of Sciences." The inscription on the Juvisy pyramid is similar. Both these monuments are about ro metres high, and are situated on the side of the carriage road leading from Paris to Fontainebleau. There is a very great deal of scientific interest attached to the basis alluded to, it having been the first work of the kind ever accurately done, and thus the basis of nearly all such measure

ments.

Kinds of Rocks met with during the Boring of the Tunnel through the Western Alps between Modane and Bardonèche. -Elie de Beaumont.-A very lengthy paper, accompanied by a catalogue of the specimens of rocks which have been presented to the Academy, and will in future form a most important mineralogical collection; the more so, because the tunnel, usually known as the Mont Cenis tunnel, will be lined over its entire length (12,220 metres) with bricks and tiles, and the rocks will be hid. As may be expected, this paper, by so eminent a geologist and mineralogist, is of very great value.

Answer to the Remarks made by M. H. Sainte-Claire Deville on the Variations of Temperature Produced by the Mixing of Two Liquids.-Dr. Jamin.-And

Reply to that Memoir by M. H. Sainte-Claire Deville.We can only give the titles of these polemical discussions between the rival physicists.

Action of Water upon Iron, and of Hydrogen upon Oxide of Iron. (Third memoir on this subject).-H. Sainte-Claire Deville.The author resumes the results of his experiments in the following terms:-The increase of the tension of hydrogen formed by the con

tact of iron and steam, is a continuous phenomenon when the tension of the steam is made to vary progressively without any variation of the temperature of the iron. That the tension of the hydrogen corresponding to an invariable tension of steam, decreases continually when the temperature increases progressively. That the same laws are observed at the inverse phenomenon of the reduction of oxide of iron by hydrogen.

Isomers of Cyanuric Ethers.-Reply to M. S. Cloëz, by Prof, A. W. Hofmann.

Meteorology of the Spring of the Current Year.-M. Chapelas -The author considers (1) the temperature, (2) the direction of the winds, (3) the moisture, and draws up a series of comparisons, taken from the meteorological records of former years, to elucidate the meteorological conditions of last spring.

On a Property of the Volta Electrical Condenser hitherto Unnoticed.-P. Volpicelli.-An algebraico-physical memoir.

Deluc's Thermometer.-M. Legrand.-A discussion on the precision of a thermometer scale now almost obsolete, so that this paper is of very little interest.

Compressibility and Expansion of Gases.-Dr. Amagat.

Phospho-Platinic Compounds.-P.Schützenberger.-The author states that he has succeeded in isolating the radical of phosphoplatinic compounds before alluded to. The radical turns out to be a black coloured body, insoluble in water and soluble in alcohol; the formula being Ph(CHO),Pt.

Carbonic and Alcoholic Fermentation of Acetate of Soda and Oxalate of Ammonia.-A. Béchamp.-This lengthy memoir is divided into the following sections:-Carbonic and alcoholic fermentation of acetate of soda; carbonic and alcoholic fermentation of oxalate of ammonia; production of alcohol from the elements of air and water. As regards this latter point, the author asserts that he took very pure distilled water, and poured it into a flask, the mouth of which was simply covered by a piece of paper; after having been set aside for some six months, the author has extracted enough alcohol from the water to ignite. He supposes the cause of this phenomenon to be the formation of microzymas, which induced fermentation. Some ammonia and a volatile acid were simultaneously formed.

Climate of the Elsasz and the Vosges.-C. Grad.

Observation on an Unequal Production and Difference of Composition of the Milk from the Breasts of the same Woman. -L. Sourdat.-While the quantity of sugar and salts contained in the milk of the two breasts of the same woman does not perceptibly vary, the author has found that the milk of the right breast contains more butter and caseine than that of the left breast, the difference being as much as in the ratio of 9 to 1.

Bulletin de la Société d'Encouragement pour l'Industrie Nationale, No. 208, April, 1870.

This number contains the following original memoirs and papers relating to physico-chemical and collateral sciences:

Report, by M. Tresca, on the System of Water-Wheels Invented by M. Sagebien.-A very important memoir, illustrated by engravings, on this subject, since the inventor has successfully solved the problem of applying usefully low falls, or weak currents of water, so as to become, by means of the wheels arranged by him, fit for very cheap, yet effective, motive power.

Report, by M. Clerget, on an Apparatus wherein a Continuous Jet of Liquid, and a Gradually Increasing or Decreasing Temperature, are Applied to the Cleansing of Linen Fabrics.Description, illustrated by engravings, of an apparatus invented by M. J. Decoudun, 77, Rue Montreuil, Paris.

Manufacture of Special Kinds of Cast-Iron.-S. Jordan.-The author discusses, at great length, the calorific phenomena produced by the injection of compressed air, steam, or oxygen into a mass of molten iron, from a multiple of jets.

Effervescing Cyder.-MM. Brosse and Lamfrey.-Cyder, it is well known, becomes, when bottled, after being freshly-made and pure, effervescing to a high degree, but then, also, a highly-intoxicating beverage. The authors apply to cyder a preparation (not specified) whereby it becomes effervescent and a pleasant useful beverage which keeps well for any length of time.

Gaize.-J. Desnoyers.-The substance known as gaize, or pierre morte, is a mineral largely met with in the department of the Ardennes, where it forms a deposit of some 100 metres' thickness. Its sp. gr. is 148, and it consists, in 100 parts, of-Soluble silica, 44'8; insoluble silica, 42'0; alumina, 5'1; peroxide of iron, 25; lime, a trace; hygroscopic and combined water, together, 5'4. It is, on being dug up, quite soft, so that it can be cut with a knife, but becomes hard on drying, and very hard when exposed to red-heat, whereby its specific gravity is reduced to 1'44. This material is essentially a substance capable of withstanding high temperatures; and the author exhibits crucibles made from the gaize, which have been used successfully for melting iron. Dr. La Salvetat, the celebrated chemist of the Imperial Porcelain Works, at Sèvres, states that layers of similar material exist in the central parts of France, likewise deposited in the cretaceous formation; he also states that these minerals are of great value for the construction of blast and other furnaces.

Alloy of Cobalt and Manganese.-A. Valenciennes.-The author exhibits, at the meeting of the Society, samples of metallic cobalt and ganese, which resemble those of copper and tin. The alloys of cobalt manganese, and alloys thereof, as well as alloys of copper and man

Annales de Chimie et de Physique, June, 1870.

This number contains the following original papers and memoirs:Superficial Tension of Liquids, as deduced from Certain Movements which Take Place on their Surface.-G. van der Mensbrugghe.-The concluding portion of this memoir.

Indices of Refraction of Gases and Vapours, and on the Measurement of their Dispersion.-Dr. M. Croullebois.-This lengthy essay is divided into the following chapters:-The history of the subject; description of instruments, illustrated by woodcuts; indices of gases for homogeneous lights; dispersion of gases; first method, and observations thereon; second method; indices of gases in white light; indices of vapours in homogeneous and white lights; dispersion of vapours, method employed, and description of apparatus, illustrated by woodcuts.

Apparatus Arranged for the Demonstration of the Physical Properties of Vapours.-F. da Fonseca Benevides.-This paper cannot be understood without the reproduction of the annexed cut. The contrivance is simple and effective, and suited to demonstrate, experimentally-The laws of the boiling of liquids and absorption of latent heat; the influence of pressure upon the temperature of the boiling liquid; condensation of vapours (steam and others); development of latent heat; relation between pressure and temperature; production of cold by the dilatation of vapours under high pressure; use of steam as motive power; action of the Giffard's injector.

Evaporation of Water and the Decomposition of Carbonic Acid by the Leaves of Plants and Trees.-P. P. Dehérain. This lengthy memoir,containing a series of results of experiments exhibited in a tabulated form, is divided into the following sections:-History of the subject, method of experimenting; quantity of water evaporated by leaves exposed to sunlight in one hour; influence of light upon the evaporation. The luminous rays which provoke the evaporation also cause the decomposition of the carbonic acid. Rays of light of the same intensity, but different colour, exert different action, as regards the decomposition of carbonic acid and the exhalation of water.

Estimation of Graphite in Carburetted Iron.-M. Boussingault. -The results of the experiments and analyses detailed at length in this paper, may be summarised as follows:-(1) When a carburetted iron is dissolved in chlorhydric acid, the total quantity of the carbon combined with the metal is eliminated, while the free carbon remains mixed with the other substances insoluble in the acid. (2) Since the residue left by a grey cast-iron, treated by hydrochloric acid, contains a portion of the silicium which was combined with the iron in the state of silica, that residue does not contain any graphitoid silicium nor protoxide of silicium; the estimation of the silica in the residue does not represent the whole of the silicium contained in the cast-iron, because a portion of the silica remains in the acid liquid. (3) That the process based upon the difference of combustibility of the combined carbon and graphite is sufficiently exact to estimate the two kinds of carbon obtained by the action of bichloride of mercury upon the carbonaceous residue of cast-iron or steel.

Description of Electrophoric Machine Suitable to Charge Batteries.-P. Riess.-Illustrated with woodcuts.

Measurement of the Absorption of Light by Transparent Media by means of the Spectrum Apparatus.-Dr. C. Vierordt. Observations on Induction Sparks.-Dr. A. Weinhold.

Annalen der Chemie und Pharmacie, May, 1870.

This number contains the following original memoirs and papers:Researches on some of the Derivatives of Cinnamic Acid. -C. Glaser.-Third part of this essay, divided into the following sections:-Phenyl-propiolic acid, C,H,O,; formation of phenyl-propiolic acid from bromstyrol; formation of phenyl-propiolic acid from a bromo-cinnamic acid; constitution of phenyl-propiolic acid; formation of acetenyl-benzol from phenyl-propiolic acid; formation of acetenyl-benzol from styrol; metallic combinations of acetenyl-benzol acid); derivatives from styrol; chiorinated styrols; brominated styand its conversions (diacetenyl-phenyl; synthesis of phenyl-propiolic rols; conclusions and speculative discussions.

On Mercuro-Ditolyl.-E. Dreher and R. Otto.-This compound

is obtained by the action of sodium-amalgam upon brom-toluol. It is, as crystallised from boiling benzol, a beautifully white body, exhibiting a strong diamond-like lustre, and crystallising in large rhombic-shaped crystals, insoluble in water, difficultly so in alcohol, best in benzol, chloroform, and sulphide of carbon, and fuses at 235°. The authors describe, at length, the action of the haloids, and of nitric, hydrochloric, hydriodic, and sulphuric acid upon this body; and next treat of acetic acid-mercuro-monotolyl

CHCH2

C2H2O-0

Hg

Annalen der Physik und Chemie, von Poggendorff, No. 5, 1870. This number contains the following original papers and memoirs

Sound Emitted from Heated Tubes, and on the Oscillation of Air in Pipes of Different Shape.-Dr. C. Sondhauss.

On Chromates.-C. Freese.-The author has studied some of the hitherto less known salts of chromic acid. Among these we noticeNormal chromate of silver: Attention is called to the mode of precipitating this salt, which differs in composition with the concentration of the silver and chromate solution employed; the normal salt contains 65 per cent of silver and 15 83 per cent of chromic acid. A basic chromate of silver does not exist; a bichromate is well known. Chromate of protoxide of mercury, HgCr40, in 100 parts-Hg, 77'49; Cr, 10'11; O, 12'40. Chromate of deutoxide of mercury, 3HgCrбO, in 100 parts-Hg, 80'19; Cr, 698; O, 12:83. The chromates of copper are treated of at great length, and the subject is to be continued in a following number.

Thermo-Chemical Researches.-J. Thomsen.-The continuation of the author's very lengthy memoir on this subject, this portion treating on the acids of nitrogen, phosphorus, and arsenic.

Continued Researches on Liquid Conductors of Galvanic Electricity.-J. W. Müller.-The first instalment of a lengthy essay on this subject, subdivided as follows:-Introduction and description of method of investigation, illustrated by diagrams; on the tension of liquid conductors in general; the non-dependence of the tension of alkali and acid upon their chemical combination; first general laws of the direction of the current, and of the electro-motive force of the acido-alkaline conductors; tensions of the alkalies and the acid, and of the salts formed by their union; saline solutions at the end of each pair of metals; effect of dilution of saline solution; effect of concentration of saline solution.

Investigation on the Electric Dust Figures (Staubfiguren). -W. von Bezold.

Laws of the Formation of Kundt's Dust Figure.-T. Karrass. -These two papers refer to what are sometimes termed Lichtenberg's

Conversion of Thiophenol (Phenyl-Sulphydrate) into PhenylBisulphide.-E. Dreher and R. Otto.-After referring to the different methods of effecting the conversion alluded to, the authors state that this object can also be attained by heating the mercurial compound, (CH),S2Hg=(C&H ̧),S2+Hg.

Two Isomeric Pentachlorbenzols and BichlorbenzolChloride.-R. Otto.

Mercuro-Dinaphthyl.-R. Otto.-This paper is divided into the following sections:-Preparation of mercuro-dinaphthyl; action of iodine upon mercuro-dinaphthyl; mercuro-mononaphthyl-bromide; behaviour of mercuro-mononaphthyl-iodide with nascent hydrogen and sodium-amalgam; formic and butyric acids, mercuro-mononaphthyl.

Sulpho-Toluide. R. Otto and A. Gruber. - Sulpho-toluide, CHSO, is, when obtained in crystalline state from benzol, a solid body, exhibiting klinorhombic-shaped prismatic crystals; fuses at 155; insoluble in water, and difficultly soluble in cold alcohol and ether; rather more soluble in boiling alcohol, benzol, and chloroform. When submitted to the action of heat, in small quantities, it is volatile without decomposition. Heated along with concentrated sulphuric acid, it is gradually converted into toluol-sulphuric acid. The authors quote, at length, the various reactions of this body with several reagents, and discuss its constitution.

Acetic Acid Mercuro-Monomethyl and Acetic Acid MercuroMonoethyl.-R. Otto.

Preparation of Organic Sulphur Compounds by means of Hyposulphite of Sodium.-R. Otto.-When ethyl-alcohol is heated for twenty hours, in a sealed tube, with a hot concentrated solution of hyposulphite of soda, it is converted into mercaptan. Iodethyl, heated for two hours to 150°, in a sealed tube, is converted into sulphur compounds, and iodide of sodium is formed.

Diamido-Nitrophenylic Acid, a New Derivative from Picric Acid.-P. Griess.

Azobenzol-Sulphuric Acid.-P. Griess.

Ozone and Antozone.-C. Engler and O. Nasse.
Constitution of Arbutine.-H. Schiff.