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has only to open the ash-pit doors again the requisite | distance to admit the proper amount of draught to each furnace. This plan I found to have the advantage of making the fires burn more regularly, as the fireman, from having to open and close the ash-pit doors oftener, had his attention directed to them, and so the draught was better regulated. I am, &c.,

May 20, 1879.

E. H.

PS.-I may say that the furnaces and ash-pits were furnished with closely-fitting doors.

WASH-BOTTLES WITH CONTINUOUS JET.

To the Editor of the Chemical News. SIR,-In the CHEMICAL NEWS, vol. xxxix., p. 19. Mr. Foye called attention to a wash-bottle giving a continuous jet of water, and Mr. Mallet, in your issue of May 2, has described a more complete but complicated form of the same. In both these cases the essential feature is a piece of caoutchouc tubing, so arranged as to permit the air inside the bottle being cut off from the external air by pressure with the finger. Will you kindly permit me to say that I described a bottle having this arrangement, and also the Bunsen valve, in a paper read before the Chemical Society in March, 1877. A short abstract appeared in your journal. The following is an illustrated description of the washbottle:

b

It has two tubes fused into it at right angles, which are bent round upon the top of the cork, and connected by a piece of good caoutchouc tubing (b). The tube (a) is stopped between the two junctions of the side tubes by a piece of cork (d), or by being fused up. When the operator wishes to use the bottle he holds it as usual, placing his forefinger upon the caoutchouc (b), so as to prevent air passing through it, and blows through the mouthpiece into the bottle. After this the jet of water continues to issue with almost undiminished force for about three-quarters of a minute, while it may be stopped at any time by releasing the pressure upon the caoutchouc tube (b). Water may be poured out through the new tube (a) as usual. It is convenient to bend the lower end of the tube dipping into the water; this enables the operator to blow out the last portions of water. The advantages of the bottle are as follows:-The jet will issue for some time after the operator has blown into the bottle, and can be directed upwards into a beaker by inclining the bottle. The j t can be stopped at pleasure. The water passing through the new tube when the bottle is inverted can be regulated to a drop by pressing upon the rubber. The mouthpiece never gets hot, nor does gas or steam pass through it into the mouth. When the water is boiling, if the bottle be occasionally

gently shaken, enough steam is liberated to impel the jet. Lastly, the bottle can be used as an ordinary one by blowing into the new tube without pressing the caoutchouc. trouble in making the bottle. A caoutchouc stopper is the After the tube (a) is made or purchased there is no extra best to use, but a good cork answers perfectly well. Messrs. Jackson, of the Barbican, at my request have kindly con sented to keep a few of these tubes in stock. Several of these bottles have been in constant use for two or three years in the Chemical Laboratory of the Royal College of Science, Dublin, and have given great satisfaction.—I am, &c.,

14, Mincing Lane, London, May 5, 1879.

THOMAS BAYLEY.

THE VITRIOL MANUFACTURE,

To the Editor of the Chemical News. SIR,-In the CHEMICAL NEWS (vol. xxxix., p. 205) Mr. regarding the loss of nitre. What I said then-I was speaking from memory-was perhaps scarcely justified by the facts; still, the quantity of nitre unaccounted for in our The quantity of nitre used during the six months was case is very much less than that mentioned by Dr. Hurter. 1.66 per cent on the stone burnt, equal to 37:18 lbs. to the ton. If we assume the real nitrate of soda present to be equal to 95 per cent, this would be equal to 35°31 lbs. There was found in the outlets nitrous gases equivalent to 15 lbs. nitrate of soda for each ton of stone burnt, which would give 42.5 per cent on the quantity used, or four times that mentioned by Dr. Hurter. If we add to this 10 per cent for imperfect denitration, and 5 per cent for mechanical losses, we get a total of 57.5 per cent unaccounted for. During the six months these trials were made much acid was drawn from the chambers for manure making, and this acid always contained a quantity of nitre; indeed, so much was this the case on some occasions as to interfere with the workmen while mixing in the vat. It is impossible to say how much was lost in this way, but it will be readily seen that much more than 45 per cent of the nitre is thus accounted for, without putting down 20 per cent as reduced to nitrous oxide, as is done by Dr. Hurter. I may say that we are still finding in the outlets between 40 and 50 per cent of the nitre used. But is it not probable that the different results obtained are due in a great measure to the different way in which the chambers are worked? This we know from experience-that where the chambers are worked with the acid strongly impregnated with nitrous gases much less nitre is required than where the acid in the chambers stinks of sulphurous acid.

G. E. Davis has referred to a statement I made to him

Much has been said regarding the state of oxidation of the nitrous gases found in the outlets, but no one seems to have made any direct attempt to ascertain what that state of oxidation is. observations on the reducing action of As2O3 in the ab. Directly after Mr. Davis published his sorber, I commenced a series of experiments to settle the question, at least as far as these works were concerned. In all fifty-five tests were made, and out of these in fortythree cases the gases existed as N2O3 and N2O4, while in the other twelve the gases existed as N2O2 and N2O3. It was necessary in making these experiments to assume that the nitrous gases were present in only three forms of oxidation, viz., as N2O2, N2O3, and N2O4, and that only two of these, either N2O2 + N2O3 or N2O3 + N2O4, were present at the same time. This assumption is, I think, warranted by the properties of the gases, for we should scarcely expect N2O2 and N2O4 to exist together side by side without reacting upon each other.

Mr. Davis has attributed the presence of N2O2 in the outlets to the reducing action of As2O3 exerted while the acid is passing down the absorber. Now I have reason to believe that under certain conditions sulphurous acid is competent to reduce the nitrous acids. I give below two

228

Chemical Notices from Foreign Sources.

instances, copied from my note-book, which will tend to support this belief:-"The chambers had been working with very great regularity for a length of time, the quantity of nitre used being equal to about 1 per cent on the stone burnt, and the quantity found in the outlets equal to about 12 lbs. on the ton of stone. On the 16th the chambers were looking badly, and I examined the pipe between the absorber and the last chamber when the gases smelt quite sharp. Accordingly, I expected to find a large quantity of SO2 present (in the test solutions) this morning. I was surprised to find only a trace as usual, while that of nitre had more than trebled, viz., 43°31 lbs. to the ton of

stone."

The next case is still more conclusive:-" Two days ago the acid from the absorber contained nitrous acids equivalent to 2:45 per cent of nitre; this morning it contained 107 per cent. During this time, the Glover tower being out of repair, has not been working, and it was thought advisable to put the same acid over and over again through the absorber. While this was going on the chambers have been stinking, and it was inferred that a large quantity of SO2 would be found going away. This has not proved to be the case, as only a trace has been found in the test-bath yesterday and to-day, although 6 cubic feet of the gases have been tested on each occasion. The nitre found in the outlets has been very large, viz., 102.8 lbs. per ton of stone yesterday and 1207 lbs. per ton of stone to-day."

Now these two cases would point to the fact that SO2 is capable of reducing the N2O3, in solution in the acid, to N2O2; thus, N2O3+SO2=N2O2+SO3, and that this reaction may take place in the absorber.-I am, &c.,

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{CHEMICAL, NEWS,

aluminic chloride upon acetic and sulphuric anhydrides. MM. Riodinine and Saytzeff describe diallyl-isopropylcarbinol as a colourless liquid, of sp. gr. o8512, and boiling-point 182° to 185°. MM. Semlianitzine and Sayt. zeff have investigated the oxy-valerianic acid obtained by the oxidation of allyl-dimethyl-carbinol. MM. Beilstein and Kourbatoff have obtained nitro-phthalic acid by oxidising nitro-naphthalin by means of chromic anhydride. Researches on Sulphates.-A. Etard.-The sulphates of the magnesian series, or of the alum series, are far from representing all the combinations which sulphuric acid forms with the metals. Many of these salts may be represented by the general formula M2(SO4)6N2. He has examined the double sesqui-sulphate of iron and alumina (acid); that of iron and chrome (acid); the corresponding neutral salt, &c. The sesquisulphate of aluminium and manganese is a powder of a beautiful sky-blue. the Mechanical Properties of Steels.-V. Deshayes. Relations between the Chemical Composition and -Carbon renders steels rigid and elastic, increasing their elastic tension, but their resistance to rupture diminishes if 0'500 is exceeded. Manganese renders steels rigid and tion and contraction remain considerable, which gives a elastic and increases their elastic tension, but the elongagood resistance to a shock. Silicon plays the same part as carbon, rendering steels hard, and slightly diminishing elongation. Sulphur decreases the breaking strain and the resistance to a shock. Phosphorus renders steels deficient in body, and, if its proportion exceeds 0.250 per cent, fragile on receiving a shock. Chrome acts like manganese but more energetically.

Thermic Formation of the Compounds of Carbonic Oxide with the other Elements.-M. Berthelot. -Already noticed.

Specific Heats and Melting Heat of Gallium.-M. Berthelot. The specific heat of liquid gallium is o‘0802; that of solid gallium o'079. The melting heat is +1911. CHEMICAL NOTICES FROM FOREIGN The specific atomic heat in the liquid state is 5'59; in the

SOURCES.

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

Comptes Rendus Hebdomadaires des Séances, l'Académie de des Sciences. No. 15, April 14, 1879. Anomaly in Magnetic Observations at Paris.-C. Flammarion.-The author contends that the explanations of these anomalies put forward by M. Marié-Davy are not satisfactory.

Bulletin de la Société Chimique de Paris,

No. 5, March 5, 1879. Recent Paper by M. B. Aronheim.-P. Schützenberger.-M. Aronheim having stated in the Berichte der Deutsch. Chem. Gesell. that on attempting to prepare the acetates of chlorine and iodine he had obtained mere mixtures of acetic and hypochlorous acids, or of chloride of iodine and iodic acid, M. Schützenberger refers to numerous chemists who have seen and examined, or have themselves prepared, the products in question.

Chloro-stannates of the Rare Earths.-P. T. Cléve. -The composition of the lanthanic, ceric, didymic, and yttric chloro-stannates is quite analogous to that of the corresponding chloro-platinates. The author has verified the researches of M. Marignac on the earths of the gadolinite. No doubt can exist concerning terbia. He has obtained a small quantity of ytterbia, but his researches are not completed.

Russian Chemical Society, December 7/19, 1878.M. Beketoff communicated a paper on the determination of the atomic heat of hydrogen in its combination with platinum. M. Andrianowsky has examined the action of

solid 5:52.

Reciprocal Displacements of Weaks Acids.-M. Berthelot.

Rotatory Power of Styrolen.-M. Berthelot.-These two papers have been already noticed.

Justus Liebig's Annalen der Chemie,
Band 195, Heft 3.

Products of the Action of Caustic Potassa upon
Sulpho-mesytelenate of Potassium.-Oscar Jacobsen.
-An extensive paper in which the results obtained by
Fittig, Hoogewerff, and others are critically examined.
Among the products of the reaction are mesitol, oxy-mesi-
tylenic acid, oxy-trimesinic acid, and oxy-uvitinic acid.
described at length.
These compounds with a number of their derivatives are

Analysis of Organic Bodies Containing Halogens or Nitrogen.-Hugo Schiff.-The author describes with slight modifications the method proposed by Piria thirty years ago. The substance is weighed in a small platinum crucible, and in case of chlorine or bromine fills up with a mixture of 1 part anhydrous carbonate of soda and 4 to 5 parts of lime, the whole being thoroughly mixed then covered with a larger platinum crucible and the pair together by means of a platinum wire. The whole is turned downwards. The space between the two crucibles are inverted so that the bottom of the larger crucible is is filled with the same mixture of lime and soda, the lid

is put on, and the whole heated to redness over a strong Bunsen burner. The reaction is completed in about ten minutes. In case of an iodine compound carbonate of soda is used without lime. The arrangements for the determination of nitrogen cannot be intelligibly describe without the aid of the accompanying plate.

NEWS

The Molecular Magnitude of Indigo.-Dr. E. v. Sommaruga.-The author finds the vapour-density of indigo 945, and concludes that the formula for indigo must be C16H10N2O2 and not the half of these numbers. Communications from the Laboratory of Applied Chemistry of the University of Erlangen. These communications embrace the following papers:-Detection of Ethyl-diacetic Acid in Urine, by A. Hilger; on Solanin and its Decomposition Products, by A. Hilger; and, Certain New Salts of Uranyl, by Dr. R. Sendtner. Influence of the Isomerism of the Alcohols and Acids on the Formation of Compound Ethers.-N. Menschutkin.-An important paper which does not admit of useful abstraction.

Contribution to a Knowledge of Polyporic Acid. -C. Stahlschmidt.-The author obtains hydropolyporic acid by treatment with caustic alkali, examines the salts of the new acid, obtains nitropolyporic acid by treating polyporic acid with concentrated nitric acid and certain chlorine compounds by the action of potassic chlorate and hydrochloric acid.

Contributions to a Knowledge of Ammoniacal Mercury Compounds.-H. Gerresheim.-An examination of Millon's base. The author announces an intention of shortly making known an application of this compound in water-analysis.

Moniteur Scientifique, Quesneville.
April, 1879.

Researches Conducted in the Laboratory of MM. P. Monnet and Co. at La Plaine.-P. Monnet, F. Reverdin, and E. Noelting.

Presence of Meta-nitro-toluol in Nitro-toluol.-The authors, in experimenting upon the acetylic derivative of a commercial toluydin free from aniline, were led to suppose that in addition to the ortho- and para-derivatives it contained a little of the third isomer or meta-compound. To decide this question they have studied the nitro-toluol used in the manufacture of the toluydin in question, and found their suspicions confirmed.

The Part of Meta-toluydin in the Manufacture of AnilineRed. The function of ortho- and of para-toluydin in the preparation of magenta has been studied by M. Rosenstiehl and other chemists; it seemed to the authors interesting to complete these observations by oxidising meta-toluydin either alone or mixed with aniline and the two other toluydins, especially as the presence of this base in a small extent had been traced in commercial toluydin. They have heated various mixtures containing metatoluydin with arsenic acid under the usual conditions for the manufacture of magenta and have extracted the colouring matter produced, and tested it by dyeing comparative samples :

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Shade of the Product of Oxidation. Violet (violanilin).

Red.

Yellowish brown. Brown.

Red.
Red (para-rosanilin).
Violet.

Yellowish and greyish red.

Red, slightly violet, and greyish.

Red (ortho-para-rosanilin).
Red.

Red, violet, and greyish.
Brown.

Red, violet, and greyish.

Artificial Alizarin.-C. Græbe and C. Liebermann.— The first part of this bulky treatise deals with the chemistry of artificial alizarin as understood down to 1874. Of the second part, which gives an account of subsequent improvements as far as the end of 1877, we shall shortly give an abridgment.

Contributions to the History of Benzol-green and Malachite-green.-This paper consists of certain memoirs by O. Dobner and by O. and E. Fischer, taken from the Berichte der Deutschen Chemischen Gesellschaft.

Industrial Society of Mulhouse.-Proceedings of the Sessions of the Chemical Committee, December 11, 1878, and January 15, 1879.-Nothing is here described which has not been already noticed. The particulars of M. Kopp's process for the spectral analysis of dye-wares are not yet made known.

On Amber.-M. Helm.-Amber in entire fragments is permeable to water. It contains as much as 4 per cent of sulphur in the state of organic combination. This sulphur has probably been absorbed by the fossil resin in the state of hydrogen sulphide subsequent to its formation. The author describes another fossil resin, gedanite, which differs from amber by containing a smaller proportion of oxygen, and is softer, more fusible, and more soluble in ether. It is free from succinic acid.

Verhandlungen des Vereins zur Beforderung des
Gewerbfleisses. February, 1879.

The Manufacture of Magenta by Coupier's Process. - Dr. C. Hæussermann.— - The author remarks that establishments, and although the magenta thus produced Coupier's process has hitherto been adopted in but few is often preferred, especially as a raw material for the preparation of superior blues, it is not yet finally decided which of the two methods is preferable. For Coupier's process it is essential to use an aniline oil of sp. gr. 1'006 to 1'007 at 15°. It is converted into hydrochlorate with the presence of as little water as possible. To prevent the aniline hydrochlorate when dehydrated by a temperature of 140° from adhering too firmly to the sides of the vessel, two-thirds of the aniline to be used is slightly supersaturated with hydrochloric acid, concentrated till the temperature rises to 140°, and the remaining one-third of the aniline is then poured into the melted cooling mass. This operation is conducted in enamelled pans provided with a condensation apparatus. The mixture of aniline and aniline hydrochlorate is then introduced into the melting pans, adding to 100 parts of aniline about 50 parts of pure nitro-benzol, and by degrees 3 to 5 parts of iron filings. March, 1879.

Ammonia Soda and the Production of Ammonia in Coke-burning.-Dr. Frank.-The author points out that the weak point of the Solvay process is its dependence on the supply and consequent price of ammoniacal salts. He insists upon the importance of utilising the volatile products-ammonia, tar, &c.-from coke works, which he considers would effect a revolution in all trades based upon the destructive distillation of coal.

Test for Mercurial Vapours.-At a recent meeting of the Society of the Physical and Natural Sciences of Bourdeaux M. Merget recommended paper steeped in the ammoniacal solution of nitrate of silver, or in chloride of palladium, as reagents for mercurial vapours much more sensitive than gold foil. This test-paper is very sensitive; a slip of sheet-copper plunged into a liquid containing I part of mercury in 10,000 remained bright after immersion, but if exposed to the ammoniacal nitrate of silver paper it occasioned a characteristic black spot. He finds that even when solidified mercury emits vapours in appreciable quantity.

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Advertisements.

SATURDAY, 24th.-Physical, 3. "On a New Harmonograph," W. J. Wilson. "On a New Induction Balance," Prof. Hughes.

MONDAY, 26th.-Royal Institution, 3. "The Intellectual Movement of Germany from the Middle of the Last to the Middle of the Present Century," Prof. Hillebrand. Royal Geographical, I. (Anniversary.)

TUESDAY, 27th.-Civil Engineers, 8.

Royal Institutior, 3. "Suggestions to Students and
Readers of History," Prof. J. R. Seeley.
Anthropological, 8.
Society of Arts, 8.

"The Contact of Civilisation

and Barbarism in Africa, Past and Present," by Edward Hutchinson.

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TO BE SOLD BY AUCTION pursuant to an Order of the High Court of Justice Chancery Division made in the Cause of Hutchinson v. Norwood 1878 H. No. 14 with the approbation of the Vice-Chancellor Sir Richard Malins the Judge to whose Court the Cause is attached by Mr. Thomas Colclough Leete (of the firm of Messrs. Branch and Leete) the person appointed by the said Judge at the Law Association Rooms Cooke Street Liverpool

afternoon.

on Thursday the 29th day of May next at 3 o'clock in the The Valuable and Extensive Chemical Works

situate at Widnes in the County of Lancaster known as Messrs. John Hutchinson and Co.'s No. 1 and 2 Works established by the late Mr. John Hutchinson and carried on by his executors since his death. The property comprises a superficial area of 71,385 square yards of land of which 16,859 square yards are freehold and 54,526 square yards are leasehold principally held for long terms of years at low ground rents 2211 square yards of the leasehold land have been sublet and chief rents amounting to £30 6s. 7d. will be included in the sale.

1 he situation of the works is exceptionally favourable for communication both by Railway and water they are divided by the St. Helen's Canal which affords a convenient means of access on peculiarly advantageous terms and they immediately adjoin the River Mersey fronting which there is a piei head in connection with No. 2 Works where goods can be loaded and discharged free from toll.

The Works have Railway communication with each other and are also immediately connected by means of sidings with the London and North Western the Sheffield and Midland and Great Northern Railways and with the Widnes Dock in which as well as in the Canal there are rights of berthage connected with the works. They also possess ample facilities for drainage and for the disposal of alkali waste on favourable terms.

The buildings lant machinery and apparatus are on a very extensive scale the greater part being of the most approved construction they are now in first rate condition and are capable of producing weekly 500 tons of sait-cake 225 tons soda-ash 75 tons caustic soda 30 tons soda crystals 25 tons bicarbonate soda and 20 tons recovered ulphur for all of which productions these works bear a most favoured character in the market There is also plant almost ready for working designed for the manufacture of about 50 tons per week of bleachingpowder by Deacon's process.

No. 1 Works consist of the necessary buildings machinery and plant for the manufacture of vitriol salt-cake soda-ash soda-crystals bicarbonate soda and sulphur with Smith's fiiters and joiner's workshops a well yielding weekly about 500,000 gallons Railway weighing machine Railway sidings a; d tramways throughout and loading and discharging berths on the Canal and Widnes Dock.

CHEMICAL NEWS, May 23, 1879.

A Chemist, trained at Royal School of Mines,

with Eight Years' practical experience, desires an Engagement. Excellent references.-Apply F. I.,C., CHEMICAL NEWS Office Boy Court, Ludgate Hill, London, E.C.

A German Chemist (Ph.D.), holding Diplomas

from University and Polytechnicum, who has already had experience in a Manufactory, seeks a Situation in a Chemical Manufactory in England. Good refererces.-Address, K. D., CHEMICAL NEWS Office, Boy Court, Ludgate Hill, London, E.C.

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In

time of charging the Kilns, a considerable escape of gases takes place. This is attended with proportionate loss of Sulphur, and with much inconvenience to the workmen, as well as annoyance to the vicinity of the Works. This may be entirely avoided by the adoption of C. Norrington's patented invention, which can be applied at moderate cost to existing Piant, as well as in the erection of new Works It may be seen in full operation on extensive Plant at Messrs. C. Norrington and Co.'s Chemical and Manure Works, Cattedown, Plymouth, where the fullest information may be obtained, with terms for license.

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NEW LIST of Collections of Minerals, Fossils, and Rocks, with prices. New List of Minerals for Chemical Purposes, Manufactures, and Research. New List of Varieties of Rocks. New List of Prices and Sizes of Cabinets for Natural History and other purposes. New Catalogue of Secondhand and New Books on Geology and Kindred Sciences. New Supplementary List of Books. New List of Sections of Rocks and Minerals for the Microscope. New List of Prices and Patterns for Geological Hammers. New List of Blowpipe Cabinets, Apparatus, and Materials. Also Implements and Appliances for practical work in Geology and Mineralogy.

Post free on application to JAMES R. GREGORY, Geologists and Mineralogists' Repository, 88, Charlotte Street, Fitzroy Square, London.

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N-2 Works consist of the necessary buildings machinery and plant TOWNSON & MERCER,

for the manufacture of vitriol salt-cake sod.-ash caustic soda bleachingpowder and sulphur with Offices and Lavatory Coach-house Stabling and Out-buildings Cooperage and Cooperage Store Locomotive Shed Smith's filters and joiner's workshops and railway wagon repairing shop railway weighing machine saw-mill mortar-mili and engine a well (weekly capacity 9c0,000 gallons) railways and tramways throughout and a pierhead and whartage on the River Mersey. The Works will be sold in One Lot as a Going Concern and the purchaser will be required to take the stock stores implements and utensils at a valuation.

The premises may be viewed on application to Major Cross at Widnes and particulars and conditions of sale may be had of Messrs. Gregory Rowcliffes and Rawle Solicitors 1 Bedford Row Messrs. G. S. and H. Brandon Solicitors 15 Essex Street Strand London of Messrs. Part Woodcock and Co. Solicitors Wigan and of Messrs. Branch and Leete Auctioneers Hanover Street Liverpool.

SOAPERY.-To be Let, on advantageous

terms, the ALBERT SOAP-WORKS, Sheffield; the only Soapery situated in the midst of a very large and increasing population. It contains five pans-one to cleanse 9 tons, two 6 tons, one 4 tons, and one 3 tons; Ley Vats; Hot Room; Steam Engine; Circular-saw Room; and all suitable apparatus. Tenant may enter on very favourable terms, and at a moderate rental.-May be seen working at any time, by applying at 69, Broad Street, Sheffield.

89, Bishopsgate Street Within,

LONDON.

Wholesale and Export Dealers and Manufacturers of

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For Analysis and the general Laboratory Use of Manufacturers and Professors of Universities, Schools, Mines, &c.

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PATENTS. Mr. Vaughan, F.C.S., British,

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THE CHEMICAL

NEWS.

VOL. XXXIX. No. 1018.

ON ELECTRIC DISCHARGES IN

ATTENUATED GASES,

AND ON CERTAIN PHENOMENA IN
GEISSLER'S TUBES.*

By H. EUGEN GOLDSTEIN.

IN H. Goldstein's memoir, communicated to the Berlin

The negative light is therefore a rectilinear radiation, which is propagated preferably in a manner almost normal to the producing surface.

12. Suppose the density of the gas and the intensity of the current in a Geissler's tube so regulated that the side of the tube shows a phosphorescent light round the cathode.

If we introduce along side of and paralled to the cathode a wire not connected with any source of electricity, according to what has preceded, the luminous wire will throw a narrow sharply-defined shadow of the nonluminous wire. As soon, however, as both wires are connected together, and thus converted into cathodes, we perceive on the side of the tube, in the middle of the light-green light, two large, dark, sharply-defined surfaces, which are bisected by a plane passing through both wires. If the wires are straight and not too short their form is

Royal Academy of Sciences, May 4, 1876, we find the oblong, with the longer sides parallel to the wires. following results :

The existence of a twofold conduction in attenuated gases, hitherto assumed, and corresponding to the so-called positive and negative light, cannot be retained. With the exception of the peculiar stratification of the negative (cathodic) light the author has succeeded in imparting all its supposed distinctive properties to the positive light. If the calibre of the tube widens in the direction

of the current, the discharge appears as a positive light. Under reversed conditions it is negative. In a number of experiments the cathodic discharge behaves as if taking place through a number of fine pores. By means of great rarefaction or, by increasing the intensity of the discharge, H. Goldstein succeeded in converting the spectrum of the positive light in tubes filled with air, nitrogen, or hydrogen into a spectrum of the cathode light. The phenomena observed by Reitlinger and Kuhn (Pogg. Ann., 141) are explained by the fact that these experimentalists made use of a tube whose gaseous contents were absorbed by the electrodes during the passage of the current. The author has repeatedly met with such tubes. Under the influence of a magnet positive light behaves exactly like the negative, and is even affected by a smaller magnetic force. If the anode is in an axial position it is surrounded by a luminous cylinder, which again is separated by a dark space from the metallic surface. The form which the electric light of the total discharge assumes under the influence of the magnet depends on the quantity of electricity passing at once. The author has specially examined the green light which appears in tubes of common glass at certain degrees of pressure and intensity of the discharge. The luminosity of the sides of the tube is not a phenomenon of fluorescence but of phosphorescence, and can change from green

to orange.

§11. The cathodic light which produces this phosphorescence is, as was already assumed by Hittorf, a rectilinear radiation, which extends from the cathode into surrounding space. Still there are essential differences between the diffusion of this remarkable motion and the likewise rectilinear movement of the light, some of which differences are here brought forward.

Hittorf observed that a body placed between the side of the glass and a point-like cathode, throws a shadow in the phosphorescent light of the latter.

Well defined, though not very sharp shadows of small objects, may be obtained not merely from a point-like or linear cathode, but also from extended negative surfaces placed at a small distance from the opaque object.

A surface which merely radiates light, e.g., an ignited body, under similar conditions throws a scarcely visible expanded penumbra.

*The Editor takes the earliest opportunity of bringing before his eaders a notice of certain researches due to H. Eugen Goldstein which have hitherto escaped his notice, and which, to a certain extent, anticipate some of the results announced in his papers, "On the Illumination of Lines of Molecular Pressure," read before the Royal Society, December 5, 1878, and "Contributions to Molecular Physics in High Vacua," read before the Royal Society, April 3, 1879.

The explanation of these phenomena is :

The negative electrode is the seat of a repulsive force, which causes every discharge-ray passing near the cathode to turn away.

cathode-rays are determined by the form of the negative The figures of the phosphorescent light produced by the surface. The head of a coin used as a cathode is reproduced in this manner with the accuracy of a portrait in the phosphorescence on the glass.

The author has also studied the stratification of the

light. This phenomenon, as regards the positive light,
appears in a continuous series of forms, whose ultimate
members have little resemblance. The brightness of the
successive strata is neither equal nor symmetrical in the
direction of the discharge. Each stratum has its maxi-
mum brightness near its negative border. Different
portions of one and the same stratum differ also in colour.
If we call the "ordinal number" of a stratum the
number which shows its successive place, counting from
the negative light, the character of every stratum may be
In all
pronounced a function of its ordinal number.
gases the stratification is sharper and more distinct the
nearer we approach the negative end of the positive light.
This proposition applies not merely to any gas, but to
tubes of any, and even compound, form. If we divide a
cylinder into a section for the cathode, and into several
other sections communicating only by narrow apertures,

we find that each stratum of each section has in each
other section a stratum corresponding to it in colour,
brightness, &c., namely, the stratum having an equal
ordinal number. Each single stratum of positive light is
an image corresponding to the formerly so-called negative
or cathodic light, and the stratified positive light consists
of a succession of complexes of negative light.

From the demonstrated identity of positive and negative light, and from the transformation of a negative "bush " into a single positive stratum, we are inversely entitled to regard every complex of negative light essentially as a stratum of positive light.

The boundary of the positive light is independent of the position of the positive pole, and also of the length of the whole discharge.

A displacement of the negative pole in the direction of the discharge effects a displacement of all the positive strata in the same direction. Tubes can be constructed which contain no positive light. With decreasing density all the strata are moved towards the positive pole, while their number decreases.

In a second memoir presented to the Berlin Academy by H. Goldstein, November 23, 1876, the author finds that a portion of the side of the tube, touched internally by a conductor, behaves exactly like a cathode, and emits light possessing all the properties of the cathodic light. The phenomena observed by H. H. Reitlinger and V. Urbanitzky, i. e., a green light opposite a conductor approximated to the tube, are hence merely the excitements which the cathodic rays proceeding from the point of contact must occasion as soon as they, in highly rarefied

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