margin of the dark space becomes concentrated at the concave side of the cup to a luminous focus, and widens out at the convex side. On further exhaustion, the dark space on the convex side touches the glass, when positive rotation takes place. 3. Green Phosphorescent Light of Molecular Impact.At very high exhaustions the dark space becomes so large that it fills the tube, and when German glass is used the sides are beautifully illuminated with a greenish yellow phosphorescent light. 4. Projection of Molecular Shadows.-The rays exciting this green phosphorescence will not turn a corner in the slightest degree, but radiate from the negative pole in straight lines, casting strong and sharply-defined shadows from objects which happen to be in their path. The best and sharpest shadows are cast by flat disks, and not by narrow-pointed poles ; no green light is seen in the shadow itself, no matter how thin, or whatever may be the substance from which it is thrown. 5. Magnetic Deflection of the Trajectory of Molécules. -The stream of molecules, whose impact on the glass is accompanied by evolution of light, is very sensitive to magnetic influence, and the shadow can be deflected by bringing a small permanent magnet near, the amount of deflection of the stream of molecules being in proportion to the magnetic power employed. The trajectory of the molecules forming the shadow is curved when under magnetic influence. 6. Focus of Heat of Molecular Impact.-Great heat is evolved when the concentrated focus of molecular rays from a nearly hemispherical aluminium cup is allowed to fall on a strip of platinum-foil, the heat sometimes exceeding the melting-point of platinum. 7. Mechanical Action of Projected Molecules.-An actual material blow is given by the impinging molecules. A small vaned wheel being used as an indicator, by appropriate means the molecular shadow of an aluminium plate is projected on the vanes. When entirely in the shadow the indicator does not move, but when the molecular stream is deflected so that one-half of the wheel is exposed to molecular impact it rotates with extreme velocity. 8. Phosphorogenic Properties of the Molecular Stream. -Substances known to be phosphorescent under ordinary circumstances shine with great splendour when subjected to the negative discharge in a high vacuum. (a.) Becquerel's Luminous Sulphide of Calcium shines with a bright blue-violet light, and when on a surface of several square inches is sufficient to faintly light a room. (b.) The Diamond is very phosphorescent. Most diamonds from South Africa phosphoresce with a blue light. Diamonds from other localities shine with different colours, such as bright blue, apricot, pale blue, red, yellowish green, orange, and pale green. One large fluorescent diamond gives almost as much light as a candle when phosphorescing in a good vacuum. (c.) The Ruby glows with a rich full red, and it is of little consequence what degree of colour the stone possesses naturally, the colour of the phosphorescence is nearly the same in all cases. In another room Prof. Guthrie, F.R.S., exhibited Broken Glass in Frames, illustrating the Fracture of Colloids. In Room V. great interest was taken in the working of the Writing Telegraph, exhibited by Mr. E. A. Cowper. The object attained by this instrument is that it enables the operator to write at a distant station many miles away, just as though he were present there himself, without requiring the use of any special signals, codes, or signs (to spell each letter as is now the practice), and without the assistance of any person to translate the signals as received. The instrument acts upon the simple • principle of communicating at all times, to the writing pen at the receiving end of the line, the exact position of the pencil of the operator at the sending station through two line wires, or, so to speak, giving the latitude and ongitude of the pencil continually, the position of the pencil vertically being communicated by one wire, and the {CHEMICAL NEWS. May 1879. position horizontally being communicated by the other wire. The pencil of the operator has two light " contact rods " jointed to it, and one of these slides over the edges of a series of "contact plates," having various resistances interposed between them and the line wire, while the other rod slides over a second set of such plates connected to the other line wire; at the receiving end of the line each of these wires actuates its own needle. The two needles (which are placed at right angles to each other, and are provided with light springs) actuate one writing pen, so that the pen moves up or down, and backwards or forwards, in exact obedience to the motions of the pencil in the hand of the operator at the distant station. Both the paper written upon in pencil by the operator at the sending station and that written upon in ink by him at the receiving station move along as the writing proceeds, and the messages have only to be cut off from time to time, wound round a piece of card and sent out to their destination, or put into an envelope and dispatched. In the Meeting Room Edison's Loud-speaking Telephone was exhibited by Mr. Arnold White and Mr. C. P. Edison. Messrs. Preece and Stroh exhibited a synthetic curve machine, and frame of curves produced thereby. Automatic phonograph. Electromagnetic vowel-sounder. Stereoscopic curves. Synthetic sounder and syren. Phonautograph. Mr. J. Browning exhibited a diffraction spectroscope. Automatic spectroscope. Mayall's automatic spectroscope with very dense glass prisms. Automatic sunlight recorder. New bisulphide of carbon prisms. New automatic electric lamp; burns equally well horizontally or verti cally. Mr. A. Hilger exhibited a quartz spectroscope for the ultra-violet rays: constructed for the Scientific Society at Stettin under direction of Dr. Schönn. Universal Christie half-prism spectroscope. New spectroscope, devised by Professors Liveing and Dewar. Thollon high-power dispersion bottle prism. Hilger's universal variable power prism, from 2° to 10°; collection of different power prisms and pocket spectroscopes; (A to H) dispersion. Messrs. Tisley and Co. exhibited Tisley's dynamomagneto machine, with single wire on armature: "the al ternate currents are used to augment the magnetism and for external work; the armature being hollow is kept cool by a stream of water flowing through. Donkin's harmo nograph with parallel and rectangular motions. PROCEEDINGS OF SOCIETIES. PHYSICAL SOCIETY. Prof. W. G. ADAMS, President, in the Chair. MR. C. V. Boys gave an account of some experiments made by Dr. Guthrie and himself on the subject of Arago's rotation. The experiments were begun with a view to determine if the drag on a copper disk when a magnet is made to revolve beneath it, or on the magnet if the disk is made to revolve above it, could be made use of for determining the velocity of running machinery. They made the magnet revolve and obtained the angle of deflection of a disk suspended by a torsion thread (the hair spring of a watch.) They found, as Snow Harris and others found before, that other things being equal, the drag is directly proportional to the speed, so that if the torsion of the thread could be relied on, and the strength of the magnet did not change, a perfect velocimeter could be constructed. They consider that this method is better than observing the deflection of a magnet over a revolving disk, as in this case they are limited to less than a right angle, and changes in the absolute magnetism of the earth would affect the results. They also determined the effect of change of distance, thickness, diameter, and nature of the disk, &c., their results agreeing with those of former experimenters. They observed that the effect of concentric circular cuts was far greater than that of even many radial cuts; and that when radial sectors were entirely separated from each other the effect was much less than when these were united at the centre. They then experimented on liquids by suspending a sphere or cylinder of the liquid between the poles of a revolving electro-magnet, and succeeded in getting a decided and measurable effect. The importance of this is very great, for they have thus a means of determining the conductivity of liquid electrolytes by currents induced in the liquid without the use of electrodes and without polarisation. Dr. GUTHRIE stated that as the push on the liquid is directly proportional to the current quantity they hope to measure the conductivities of liquids, and connect these to the conductivity of solids through the intervention of mercury. In reply to Prof. Adams, Mr. Boys said that the angle of deflection of the conductor had proved to be proportional to its conductivity. Dr. O. J. LODGE suggested that the conductivity of the disks used in these experiments should be determined by plotting out the equipotential surfaces. Dr. SYLVANUS THOMPSON recommended trying conducting jellies in these experiments, and Dr. GUTHRIE replied that such were being prepared for trial, including the permanent jelly made by dissolving gelatine in anhydrous glycerine at 100°. Prof. SYLVANUS THOMPSON then communicated five laboratory notes from University College, Bristol. The first related to the source of sound in the Bell telephone receiver. Two theories are now being discussed as to this effect, the molar theory regards the motion of the diaphragm in mass as the source of sound; the molecular theory finds it in the molecular motions of the magnetic core of the instrument. Prof. Thompson applied his method of getting magnetic curves with iron filings dusted on gummed glass to this problem. He found that when no currents passed in the telephone the magnetic lines springing from the pole of the magnet are gathered together on the diaphragm opposite, over a central region, which is magnetised lamellarly, or like a magnetic shell. The rim of the plate beyond this region is, however, magnetised radially, and between these two zones there is a neutral circle. It was remarkable, too, that the lines of force touching the plate were bent back around the circle, forming a kind of valley. When the current passed in the coil in a direction so as to reinforce the magnetism, the lines are gathered more closely on the central region of the plate. If the current diminishes the magnetism the lines are, on the other hand, repelled from the plate. The neutral line is also altered. In the first case it Dr. THOMPSON next wrote on a saw blade with a magnet, and dusted iron filings on it, which arranged themselves so as to trace the writing. This is usually shown on a steel plate, but a saw retains the virtue for six or eight months. A modification of this experiment due to himself consisted in writing on the blade with one pole of a powerful battery, the other pole being connected to the end of the blade. The third "note" recommended the use of fine steel fibres, got by breaking iron gauze of 32 meshes to the inch, instead of iron filings for exhibiting magnetic lines. The fourth note showed that the lines of force got by filings fixed on cards are magnetic, that of a magnet acting as a magnet. The fifth note explained that solid magnetic "figures" could be got by coating iron filings in shellac to make them light, and floating them in water, or by mixing filings in a soft paste of plaster-of-paris, which could be cut into sections on hardening. CORRESPONDENCE. NEW FORMS OF APPARATUS. To the Editor of the Chemical News. journal, the CHEMICAL NEWS, to address a few lines to The article in question which attracted my attention is that of Mr. M. Benjamin, "On some New Forms of Apparatus," a water-bottle and a burette clamp. I am astoof new ones; as when I began my studies as a chemist in nished to see these apparatus described with the predicate the year 1871 they were quite usual things in the eyes of In a great many laboratories this my fellow students. of the Universities of Leipzig, Bonn, and that of the new water-bottle is adopted; I only mention the laboratories Polytechnische Schule of Dresden. But this the distant describer may possibly not know; I therefore draw his attention to the Zeitschrift für Analytische Chemie, by Fresenius, where he will find, Vol. II., page 190, from the H. Fresenius. This description is illustrated by a woodyear 1872, this recently devised apparatus described by cut, which differs from the one in the CHEMICAL NEWS by only showing the chief parts, the tube through which the water flows and fills the bath to a height, which is determined by a vertical tube through which an excess of water is allowed to flow out. The bath itself is left out in the woodcut, but this may, with very little imagination, easily be added. As to the other new apparatus spoken of in Mr. Benjamin's essay, I will only mention, in a few words, that this is just as old as the first, and even older. It is, and was, to be found in the catalogues of every business Lezbold, Cöln, Gehrhardt, Bonn, Noellner, Darmstadt, of chemical apparatus of some significance, such as and I do not doubt that it also is to be found in English and American businesses.—I am, &c., Renteria, April 16, 1879. DR. FERDINAND KORN. shrinks in size, in the second it expands. A small thick disk is wholly magnetised lamellarly; a disk entirely magnetised radially becomes slightly conical in shape. In the actual telephone the disk is flat at the middle and conical at the edges. As the neutral ring shifts the diaphragm will assume new nodal lines. Dr. Thompson concludes that the molecular theory is not, therefore, necessary to account for the speech of the telephone, although it may assist. As confirming this view he found LOSS OF NITRE IN VITRIOL MANUFACTURE. that with iron rings round a cardboard diaphragm and an iron centre piece the enunciation was good, though the timbre was altered; whereas with radial pieces of iron on the cardboard the timbre was good, but the enunciation bad. In reply to Prof. Adams, Dr. Thompson said that the stronger the magnet the smaller the lamellarly magnetised space became, and that with a thicker disk the neutral ring was not so well marked. Dr. LODGE suggested that the best place for the coil would be in the valley over the neutral ring, which was in an unstable condition. To the Editor of the Chemical News. SIR,-I should have thought, from Dr. Hurter's last reply to me in Dingler's Journal and for other reasons, that he would not renew the discussion upon the loss of nitre, at least upon precisely the same lines as those previously taken. But as he thinks fit so to do, and this time before the English public, I am simply compelled to reply to him once more. Those who are further interested in this matter I refer to my explicit refutations of Dr. Hurter's views and 194 Loss of Nitre in Vitriol Manufacture. CHEMICAL NEWS, May 2, 1879. statements in Dingler's Journal, vol. ccxxviii., pp. 70, 152, | exaggeration, at 25 per cent of the nitre; and he declines and 548. The principal reason why I have always contended that in the Glover tower no appreciable loss of nitre takes place is this: That notoriously since the introduction of that apparatus the consumption of nitre in vitriol works, everything else being equal, has not merely been found to be no larger than before-it has actually decreased, and, in some cases, considerably. For instance, it fell from 20 to 13 parts of nitre to 100 parts of pyrites, according to the figures furnished to me by the manager of one of the best French works, and the fact of that decrease having taken place is not disputed by Dr. Hurter himself in his German papers. But "all fear of appreciable loss of nitre in the Glover tower has vanished now," at any rate, among the general body of vitriol makers, although Dr. Hurter, and possibly a few others, take exception to that view. This I can positively affirm from numerous verbal and written communications of vitriol makers in all principal countries (whom, if need be, I could quote by name); and the fact adduced in my last letter, viz., that some of the most careful manufacturers (e.g., Schaffner of Aussig) introduce all their nitric acid through the Glover tower is a striking proof of the above. Indeed, the all but universal use of the Glover tower is the best practical refutation of the reproach cast upon it by Dr. Hurter, and before him by M. Verster. It therefore requires very w ighty and accurately defined arguments to substantiate the statement that an appreciable, let alone a large, loss of nitre takes place in the Glover tower. Has Dr. Hurter produced any arguments of that kind? He estimates the loss of nitre in the manufacture of vitriol from various sources, and lays the unaccounted-for balance to the charge of the Glover tower. It is unnecessary to say how little conclusive such a reasoning process is, for the result is only a margin, arrived at indirectly, and is vitiated by all the errors in estimating the remaining possible sources of loss. It could only be admitted if the latter estimation was in all cases based upon thoroughly reliable data. For argument's sake, and as I am extremely unwilling to open out any side issue, I will grant Dr. Hurter's statement of the "mechanical losses," amounting to 25 per cent of the nitre, or I part of nitre to 100 sulphur. Coming to the "chemical losses," Dr. Hurter declines to admit any loss of nitre by the oxidation of arsenious acid in the Gay-Lussac tower. Here he is at variance, not merely with the statements of Davis, but also with the very careful investigation of H. Hjelt (Dingler's Journal, vol. ccxxvi., p. 174). Nor can I agree with him that nitric oxide cannot escape as such, on the ground that it would be re-converted into higher oxides by the excess of oxygen present. That nitric oxide sometimes does occur in the exit-gas, even when working under normal conditions, i.e., with an excess of oxygen, is proved by the ruddy vapours which are formed at the mouth of the chimney, although the "sight" in the exit-pipe is altogether colourless. This is easily explained by the fact that there is not time for the gases to be thoroughly mixed during their rapid transit through the tower, so that in some places free oxygen, and in others NO, may be present. But now I come to Dr. Hurter's principal fallacy. This is the assumption that the "chemical loss" in the chambers themselves does not exceed 20 per cent of the nitre introduced into the system. But this is the very point to be proved, and such a proof is not even attempted by Dr. Hurter, otherwise than by quoting from Mr. Davis, to whose paper in every other respect he denies any demonstrative power. But here he should most assuredly have maintained his denial with all jealousy; for from Mr. Davis's position it might be inferred that in factories making their acid from brimstone, and working with a nitre-recovery apparatus, next to no loss of nitre should take place, as they have not to contend with arsenic ! But here I am able, as I was in my German papers, to turn Dr. Hurter's own arguments against himself. He states the "mechanical losses,” and that, as he thinks, with great to admit any "chemical loss" other than that taking place in the Glover-tower or in the chambers. Consequently, in factories working without a Glover-tower, the total loss of nitre could only be 25 per cent of that assumed as the basis of his calculations, viz., 4 parts per 100 of sulphur, that is, I part per 100 of sulphur. To this could only be added the amount of nitre lost in the chamber-acid over and above the 10 per cent allowed for already in the above 25 per cent. Mr. Davis found 8.7 and 3.6 per cent of the nitre in undenitrated chamber-acid (leaving out the "only occasionally watched" cases). Dr. Hurter's own statements in Dingler's Journal are no use to us here; for they refer to works where, in the first instance, altogether too much nitre was lost (5 per cent of the sulphur), and where, secondly, the very existence of a Glover-tower and the possibility of denitrating the chamber-acid, would, quite properly, cause this to be kept rather more nitrous than where the Guy-Lussac acid is denitrated by steam, and all the nitre contained in the chamber-acid is lost. The only statements referring to the latter case upon which I can lay my hands are the following:-Kolb (Bull. Soc. Muhl., 1872, p. 309) states the percentage of N2O3 in the "large chamber" (that from which the vitriol is withdrawn for use) =0'010 per cent, the acid containing 58.6 per cent SOH2. This is equal to 0·046 N2O3, or o·100 NaNO3 upon 100 sulphur. He does not state the amount of nitre used, but we may safely assume it at least = 4 per cent of the sulphur, and thus we arrive at only 2 per cent of the total nitre as lost in the chamber-acid. Hasenbach (Ber. der Deutsch. Chem. Ges., vii., p. 681) arrives at a loss of 31 cwts. of nitrate for 60,000 cwts. of vitriol of 66° Baumé, which he states to be about 6 per cent of the total nitre used (it is about o'19 nitre to 100 sulphur). Scheurer-Kestner (Comptes Rendus, November, 1875), in order to save his platinum stills, keeps his chamberacid rather sulphurous, and thus practically quite free from nitre; but he has himself stated that his consumption of nitric acid (at 36° Baumé) is 3 per cent of the pyrites, equal to about 4'7 nitre to 100 sulphur. Consequently, if we allow 10 per cent of the nitre as lost in the chamberacid, also for works without a Glover-tower, we are very much on the right side, according to all authorities. Now this brings our total possible loss, apart from that in the chambers themselves, for works denitrating by steam, to 25 per cent, leaving 75 per cent of the loss to take place in the chambers themselves (whether by Weber's reaction or in any other way), not 20 per cent, as allowed by Dr. Hurter. Thus the big margin claimed by him as chemical loss in the Glover-tower suddenly vanishes into thin air. a manufacturer off his guard" and "prevent further I should be the last person in the world wishful to "put search" by my statements. But I cannot certainly, on the other hand, run to the opposite extreme, and decline to accept the fact that hitherto no satisfactory proof has been given for any loss of nitre occurring in the Glovertower, and that all unbiassed evidence goes the other way. I am, &c., Technical Laboratory of the Federal Polytechnic School, Zürich. GEORGE LUNGE. The Wax of Ficus Gummiflua.-F. Kessel -This wax is a chocolate-coloured mass, which softens when heated and melts between 60° and 70°. Boiling water extracts a considerable quantity of a brown colouring matter, leaving the wax nearly white. Boiling alcohol dissolves considerable quantities of the wax, which on cooling are re-deposited in a white mass resembling cauliflower. By treatment with ether the wax may be separated into two bodies more or less soluble, the former having the composition C15H300 and the latter C27H56O. -Ber, der Deutsch. Chem. Gesell. CHEMICAL NOTICES FROM FOREIGN SOURCES. Formation of Carbonic Acid, Alcohol, and Acetic Acid in the Presence and Absence of Alcohol.A. Béchamp. The same products are generated in either case. NOTE.-All degrees of temperature are Centigrade, unless otherwise Berichte der Deutschen Chemischen Gesellschaft zu Berlin, expressed. Comptes Rendus Hebdomadaires des Séances, l'Académie de des Sciences. No. 13, March 31, 1879. Conformity of the Systems of Fractures Obtained Experimentally with the Systems of Joints Intersecting the Cliffs of Normandy.-M. Daubrée.-In general these joints form two systems, one of which corresponds to the direction, and the other to the line of the greatest slope. Convenience of Special Denominations for Dif. ferent Orders of Fractures of the Crust of the Earth. -M. Daubrée.-The joints, or as he suggests, disjoints, due to rupture, the author would call diaclases. When the fracture is accompanied by displacement he terms it paraclase, whilst as a common name for both he suggests litho-clase. Chemical Researches on a Filamentous Matter found in the Excavations at Pompeii.-S. de Luca. The filaments in question seem to be carbonised fibres of flax or hemp, and had probably been collected for lint. Thermic and Galvanometric Laws of the Electric Spark Produced in Gases.-E. Villari.-The heat developed in gases by an electric spark is proportional to the quantity of electricity which produces it. The galvanometric deviations produced by the discharge of Leyden jars are proportional to the quantities of electricity condensed. The galvanometric deviations produced by one and the same charge of the condensers are con No. 17, 1879. Reductive Action of Milk-sugar upon Alkaline Solution of Copper.-H. Rodewald and B. Tollens.— The authors point out that whilst chemists are agreed on the reductive power of dextrose, there is great discrepancy concerning lactose, I mol. of which is considered to represent various quantities of copper oxide, ranging from 6 to 8 atoms. They find that the exact quantity required is 7'47 atoms of copper to 1 mol. of milk-sugar, 6.700 mg. milk-sugar to I c.c. of Fehling's liquor. They recommend that this reagent should not be prepared in quantities beforehand; 60 grms. of the best caustic and soda are dissolved in litre of water, whilst soda and 173 grms. of re-crystallised tartrate of potash in another half litre. Equal volumes of these two liquids 34 639 grms. pure copper sulphate are dissolved separately are mixed when wanted. = Oxidation of Xylol-sulphamids.-Ira Remsen.-A reply to a communication by O. Jacobsen, which the author characterises as "almost purely personal." Formation of Ethylamin.-H. Koehler.-If the black powder produced by agitating calomel with ammonia is heated in a glass tube, through which a current of dry ethylchloride is passed, a small quantity of ethylamin is produced. Certain Colouring Matters of the Rosanilin Group. -E. Fischer and O. Fischer.—If a solution of dimethylanilin in dilute sulphuric acid is mixed with manganese the formation of violet derivatives begins at 30° to 40°. interesting paper, but not susceptible of useful Meta-nitro-phenol and its Derivatives.-A. Bautlin. abstraction. Certain Greek Tanning Materials.-Hans Jahn.— the cups of valonias, freed from scales at 22.615 per cent, The author states the average proportion of tannin in in the scales at 36.60, and in the entire ware at 33 Fer cent. Peloponesian gall-nuts contain on an avera e 47'6 per cent of tannin; pine-bark from Crete 9.818 per cent, and from Asia Minor 17.285 per cent. stant and independent of the length of the spark produced-An circuits (this name being applied either to the length of Magnetic Rotatory Power of Gases at Ordinary Pressure and Temperature.-H. Becquerel.-By means of a special arrangement which the author describes he has not merely succeeded in showing the magnetic rotation of the plane of polarisation of light at the ordinary temperature and pressure, but has been able to measure it with precision. Rotatory Magnetic Power of Vapours.-E. Bichat. -On causing the current of eighty large Bunsen elements to act upon a ray of polarised light traversing vapours of carbon sulphide the author has obtained an evident but slight deviation of the plane of polarisation. Pressure Exerted by Galvanic Deposits.-M Bouty. -Not suitable for abstraction. Behaviour of Mono- and Dibrom-acetic Ethyl ethers with Aqueous Ammonia.-F. Kessel.-The author sought to use the behaviour of these bodies with aqueous ammonia as a means for their separation, but succeeded only when the dibrom-acetic ether formed the greater part of the mixture. Etherification of Secondary Alcohols.-N. Menschutkin.-Not suitable for abstraction. J. Piccard.-Cantharic acid is a powerful mono-basic acid. Cantharic Acid and a Terpenoid Hydrocarbon.The author describes the copper and potassium salts, and the origin of cantharen, which he considers as formed from cantharic acid by the abscission of carbonic acid. Gelatinous Silicic Acid and an Inorganic Membrane.-F. Ullik.-The author has found it possible to wash the well-known jelly produced by pouring dilute solution of soluble glass into hydrochloric acid and allowing the mixture to stand. He treats the mass repeatedly with water, taking care not to break it up, and has obtained it free from hydrochloric acid and chlorides, and in the formation of membrane-like layers, which, though incapable of filtering, are capable of dialysing like an animal membrane. Contributions to the Voluminar and Steric Law.H. Schroeder.-Incapable of abstraction. Alkaloids of the Pomegranate.-C. Tanret.-The Action of Potassium Cyanate upon Epichlorhydrin. author finds that pelletierin is accompanied by three-A. L. Thomsen.-The reaction consists in the addition other volatile bases, the extraction of which he describes, of I mol. cyanic acid to 1 mol. epichlorhydrin, 196 Chemical Notices from Foreign Sources. Bulletin de la Société Chimique de Paris, Determination of the Total Nitrogen in Manures. -A. Rémont.-The author, referring to the well-known fact that when a manure contains nitrates the determination of its total nitrogen is impossible, recommends to add to the portion taken for analysis powdered white sugar to the extent of ten times the quantity of the nitiates supposed to be present, basing this approximation on the proportion of soluble matters which the manure contains. (If the manure contains soluble phosphates, salts of potassium, &c., the total soluble matter can throw no definite light on the quantity of nitrates which may be present.) The author adds the somewhat needless precaution that the sugared sample must be mixed with soda-lime before introduction into the combustion - tube lest detonation occur on heating. Production of Crystalline Chromate of Baryta.Leon Bourgeois.-Already noticed. Certain Hydrocarbides formed by the Action of Methylic Chloride upon Toluen in Presence of Aluminic Chloride.-E. Ador and A. Rillet.-This memoir does not admit of useful abstraction. Bromo-citraconic Acid.-Edme Bourgoin.-This acid, CroH6Br2O3, is bibasic, yielding alkaline and earthy alkaline salts of little stability and readily soluble in water. Relative Affinities and the Reciprocal Displacements of Oxygen and the Halogens.-M. Berthelot. -The author proposes to show that the reciprocal displacements between the halogens and oxygen, united either with the metals or the non-metallic elements, may be predicted according to the sign of the quantities of heat liberated in the formation of the compounds which these elements form with oxygen on the one hand, and with the halogens on the other. Thermo-chemical Researches on Magnesium, Calcium, Strontium, and Barium.-J. Thomsen.Along with an increasing atomic weight we find an aug. mentation in-(a.) The stability of the hydrates and the heat liberated on the hydration of the oxides. (b.) The solubility of the hydrates in water and their heat of solution. (c.) The heat of formation of the chlorides, bromides, iodides, and nitrates. On the other hand, with an increasing atomic weight we find a decrease in—(a.) The affinity of the chlorides, bromides, io dides, nitrates, and sulphates for water; the proportion of water of crystallisation and the heat liberated on its fixation. (b.) The solubility and heat of solution of the same compounds. The atomic weight bears no relation to-(a.) The heat of neutralisation of the dissolved hydrates. (b.) The total heat of formation of the hydrates, i.e., R, O, H2O.— Journal f. Praktische Chemie, xvi., p. 67. CHEMICAL NEWS, May 2, 1879. Iron and Steel Institute.-The Annual Meeting of the Iron and Steel Institute will be held on May 7, 8, and 9, at the Institution of the Civil Engineers. The programme includes papers and discussions on:-"The_Mechanical Properties of Iron and Mild Steel," by Mr. D. Adamson, C.E. "On the Use of Steel in Naval Construction," by Mr. Nathaniel Barnaby, C.B., H.M.'s Chief Constructor. "On the Use of Steel in the Construction of Bridges," by Mr. H. N. Maynard. "On the Elimination of Phosphorus in the Bessemer Converter," by Mr. Sidney G. Thomas, F.C.S., and Mr. Percy C. Gilchrist, A.R.Š.M., F.C.S. "On the Removal of Phosphorus and Sulphur during the Bessemer and Siemens-Martin Processes of Steel Manufacture," by Mr. G. J. Snelus, F.C.S., &c. "On a New Volumetric Method of Determining Manganese in Manganiferous Iron Ores, Spiegeleisen, Steel, &c.." by Mr. John Pattinson, F.I.C., Newcastle-on-Tyne. Lime or Basic Bricks and Linings for Furnace Converters, "On a Ready Means of Moulding Lime, and Making &c.," by Mr. Edward Riley, F.C.S., F.I.C., &c. "On a Practical Combination of the Bessemer and Puddling Processes," by Mr. Edwin Pettitt, Cheltenham. "On the Results of Working the Godfrey-Howson Furnaces at the Works of Tamaris, Gard, France," by M. Escalle. "On the Chemistry of Puddling," by Mr. H. Louis, A.R.S.M., Londonderry, Nova Scotia. "On a New Process for Protecting Iron and Steel against Rust," by Prof. Barff. NOTES AND QUERIES. Insurance of Tar Distilleries (Reply to W. A. R.).-Though not able to speak positively of the present time, I can certainly aver that a few years ago it was quite impossible to find any fire insurance office willing to grant the protection desired. I think it highly probable that the same state of things still exists, and, what is more, is extremely likely to do so. The tar distiller's best plan is to see to it that he sets such of his plant and materials requiring protection from the weather, under cover of the simplest and least inflammable kind. The tar-stills and other large stills worked with fire usually remain uncovered with any roof. My own experience is that with careful arrangement of plant, and proper precautions and care, there is little need for fear, and, in case of a fire even, this may, except in very exceptional cases, be quickly subdued without much damage being done. See communication on "Extinguishing Fires in Tar Distilleries, &c."-WATSON SMITH. Action of Mono-chlor acetic Acid upon the Sulpho- WEDNESDAY, cyanates of the Aromatic Monamines.-J. H. Jæger. -Aniline and toluydin, dissolved in alcohol, have been treated with mono-chlor-acetic acid along with ammonic sulpho-cyanate.—Journ. f. Prakt. Chemie, xvi., 17. MISCELLANEOUS. Royal Institution, 3. Dissociation," by Prof. Dewar. Royal Society Club, 6.30. Society of Aris, 8. "The History of Alizarin and Allied Colouring Matters, and their Production from Coal-Tar," by W. H. Perkin, F.R.S. FRIDAY, 9th.-Royal Institution, 9. "Habits of Ants," by Sir Joha Mr. W. Valentin, F.C.S.-Mr. W. Valentin, F.C.S., is about to retire from the Laboratory of the Science SATURDAY, Schools, South Kensington, formerly the College of Chemistry, in connection with which he has laboured for more than twenty years. It would be difficult to find one to whose patient work the present generation of chemists is more indebted, and a few of his old friends and pupils of the Royal School of Mines, recognising the value of his long services, are forming a committee with a view of presenting him with a testimonial. The Committee already includes Dr. Frankland, Dr. Forbes Watson, Prof. Guthrie, Dr. E. J. Mills, and Mr. W. ChandlerRoberts. TO CORRESPONDENTS. E. W.-At the Library of the Commissioners of Patents, Southampton Buildings, Chancery Lane, W.C. E. W. Young.-Such works as "Watts's Dictionary of Chemistry." "Ure's Dictionary of Arts, &c.," "Ganot's Physics," Wagner's and Richardson and Watts's works on Chemical Technology seem to already supply the information. |