mittee be appointed to inquire and report on the subject to the next meeting of the Congress : Messrs. P. W. Squire and F. Ransom (Great Britain). Profs. Remington and Rusby (United States), with P. MacEwan (Great Britain and U.S.A.), and G. P. Forrester (European Continent) as Secretaries. "This meeting recommends that the Provisional Committee shall have power to invite as members with equal rights persons who have interested themselves in this subject, and further that this resolution shall be conveyed to the Governments and pharmacopoeial authorities who were represented at the Brussels Conference (1902) on the unification of potent remedies." Section XI. i. "That the Committee of the various countries party to the International Convention for the Protection of Industrial Property be requested to consider the desirability of adopting the following provision: The manufacture in one country of the Union protects the patentee against the revocation of his patents in all countries of the Union.'" ii. "The Section recommends the question raised by M. de Laire's paper on The International Patent' to the attention of the International Association for the Protection of Industrial Property and to the National Committees for study with a view to future Congresses." iii. "That International Committees be appointed representative of all the nations party to the Congress to consider and draft proposals for joint international patent and trade mark legislation, with a view to international uniformity, such proposals to be laid before the Congress of 1912 for discussion and further action." iv. "That the Congress deprecates any patent legislation limiting the patentability of pharmaceutical products." v. To commit the question of international acknowledgment of the right of prior use within the States adhering to the International Convention to the International Association for the Protection of Industrial Property for further consideration." vi. That the Congress expresses the wish that there should be created an 'international depôt de plis cachetes.'" vii. "That it is necessary that a fancy name designating a medicinal compound of definite composition should be protected as a trade mark as securely as such a name applied to a secret remedy, or a remedy of indefinite composition." viii. "It is desirable that all manufacturing countries, notably Germany, Great Britain, and the United States, adhere to the Madrid Convention concerning international trade mark registration, and that this arrangement should be raised at the next Conference in the sense that: (a) Registration of a trade mark at the Berne Bureau should only have a formal effect; (b) that the deposit at the Berne Bureau be independent of registration in the country of origin." ix. That an International Commission be appointed for the study of technical rules defining requisites, to which should correspond the principal chemical products commercially known as commercial products." x. "That the work of this Commission should be considered as part of the work of the Congress of Applied Chemistry.' xi. "That a Sub-section dealing with the chemistry of petroleum should, in the future, be a Sub-section of the Congress." xii. "That an International Commission be appointed to establish uniformity in the control of the escape of noxious gases." xiii.That each succeeding Congress of Applied Chemistry do examine and report upon the progress and position of chemical industry in each of the countries party to the Congress, having particular regard to the country in which the Congress is for the time being held, and to the relation between the development of chemical industry and customs' tariffs." PROCEEDINGS OF SOCIETIES. PHYSICAL SOCIETY. Dr. C. CHREE, F.R.S., President, in the Chair. A PAPER on "A Bifilar Vibration Galvanometer" was read by Mr. W. DUDDELL. The paper describes a new type of vibration galvanometer and a series of tests made upon it. Vibration galvanometers may be divided into two types: (1) those in which the moving part consists of a piece of iron or steel and the current to be measured flows round fixed coils as in the case of the Thomson galvanometer; (2) those in which the current to be measured flows round a moving coil placed in a fixed magnetic field on the syphon recorder principle. The vibration galvanometers of Max Wien and Rubens belong to the first class, while Mr. Campbell's vibration galvanometer and the one described in the paper belong to the second. In the instrument described the mass of the moving parts is reduced to a minimum, the moving coil being reduced to the two wires forming its two sides, similar to a bifilar oscillograph, but with this difference :-Whereas the bifilar oscillograph is designed so as to make the damping aperiodic, the vibration galvanometer is designed so as to keep the damping as small as possible. A series of tests made upon the instrument showed that the total range of frequency was very large, namely, from about go vibrations per second up to 1900 vibrations per second. The damping is very small, so that the resonance is very sharp. A series of measurements on the sensibility of the instrument showed that the sensibility to alternating current decreases very nearly inversely as the frequency for which the instrument is adjusted, whereas for direct current the sensibility decreases approximately inversely as the square of the frequency for which the instrument is adjusted, which is what usually takes place with direct current galvanometers. The sensibility of the galvanometer for detecting small alternating voltages is reduced by the back E.M.F. of the instrument, and the paper concludes with a determination of the magnitude of the back E.M.F. in the instrument shown at the meeting. The advantages of the galvanometer are its simplicity, ease in tuning, wide range of frequency for which it can be tuned, high sensibility, negligible selfinduction, and comparatively small back E.M.F. Mr. A. CAMPBELL said that thanks were due to the author for an interesting account of the valuable and thorough investigation he had made of the behaviour of single-loop bifilar vibration galvanometers. Galvanometers of this type had been used at the Reichsanstalt for several years (Zeit. fur Instrumentenkunde, May, 1906) and had given good results with frequencies as high as 2500 vibrations per second. He did not know what sensitivity was obtained with the German instruments, but there was no doubt Mr. Duddell's pattern of the same type was much more sensitive than the instrument of the moving coil type which he (Mr. Campbell) described in 1907. Blondel pointed out in 1900 that in an oscillograph there was no advantage in having more than one turn of wire, but this appeared to be only true when the mirror was very small. As a large mirror with plenty of light and good definition greatly improved the ease and accuracy of observation, he gave the preference to a moving coil of more than one turn, even though the single-loop instrument was highly recommended by Dr. Orlich. With a CHEMICAL NEWS, June 11, 1909 } Method of Testing Photographic Shutters. 287 moderately large mirror one could obtain good definition | scale in the usual way. The specimen was heated by of a dark line with a scale distance of 600 cm. Mr. means of nickel wire heaters placed above and below it, Campbell mentioned that Wien's vibration galvanometer and the temperature measured by means of a thermo(Ann. der Phys., 1901) with very small magnets and junction placed close to the disc. The flux in the iron minute mirror gave 70 mm. at 1 metre distance for I was measured by the voltage induced in a coil of eight microampere at 100 vibrations per second and had a re- turns of bare wire wound round it. To measure the voltage, sistance of 200 ohms. Mr. Duddell's curves were most the maximum value of which was of the order of 0'03 instructive. He had verified experimentally the law which R.M.S. volts, a special galvanometer was constructed. he (Mr. Campbell) had stated from theoretical considera. This depends for its action on the forces exerted by a tions, namely, that with a given bifilar suspension (tuned rotating field on a suspended coil carrying alternating to resonance) the sensitivity varies inversely as the fre- currents. If E be the E.M.F. applied to the moving coil, quency. The figures given tended to show that the and E, the E.M.F. due to the field on the coil, then, by shorter bifilars gave reduced sensitivity. With much turning the coils producing the field round until the deflecshorter bifilars he had found great loss of sensitivity. In tion is a minimum, this deflection is proportional to EE.. the moving coil type with many turns the back E.M.F. The results of the experiments show that the effect of was considerable and might even double the effective increasing the temperature of iron is to reduce the hysteresis impedence of the instrument and lower the volt-sensitivity loss at a given induction and to cause the maximum loss accordingly. to occur at a lower value of the induction. In one specimen the maximum value of the loss at 220° C. was 12,300 ergs per cu. cm. per cycle at an induction of 16,000 C.G.S. units. At 580° C. the maximum loss was 2600 ergs at an induction of 10,700. The frequency of the experiments was 42 cycles per sec. Dr. J. A. FLEMING asked the author if he had tried his instrument with intermittent currents of the right frequency. If the galvanometer was sensitive to currents such as are obtained by rectifying trains of oscillations from condensers, it might be useful as an optical call in wireless telegraphic stations. Dr. W. H. EcCLES remarked that the effects of previous Dr. RUSSELL Congratulated the author on the notable thermal treatment, and of the nature of the material on advance he had made in the design of vibration galvano- the properties studied by the authors, were so enormous meters. He much appreciated the clear presentation and that comparison of the present experiments with similar the accuracy of the experimental results. He asked ones with alternating fields was difficult; but the authors' whether variations of the barometric pressure had any curves seemed to show that the effect of rise of temperature appreciable effect on the sensitivity of the instrument, and on hysteresis loss was less for rotating fields than for suggested that variations in the humidity of the atmos- alternating fields if the fields were below about 12 C.G.S. phere might possibly have some effect. So far as he was The curves showed also that the maximum values of aware, the author was the first to point out the importance hysteresis loss in rotating fields were reached at lower and of the back electromotive force due to the vibrating wires lower flux densities the higher the temperature, although cutting the magnetic field. He thought that the experi- the permeability varied but little. This was of importance mental results given would be a great help in formulating from the point of view of the molecular theory of maga inore exact mathematical theory of this type of apparatus.netism; it showed that smaller forces sufficed to rotate He showed that to a first approximation the author's results were in agreement with those deduced from the differential equation ordinarily given for the motion of the mirror. He asked whether the frequency of ordinary alternatingcurrent supply circuits was sufficiently steady to avoid the necessity of constant tuning of the apparatus. The CHAIRMAN asked the author if the mirror was always situated in the middle of the vibrating fibres. The AUTHOR, referring to Mr. Campbell's remarks, said considerations of space prevented him from working with scale distances of 6 metres. With regard to Wien's instrument it was easy to obtain high current sensibility but not high voltage sensibility. He had tried Prof. Fleming's suggestion, but his instrument was not sensitive enough for ordinary signals. With more uniform spark frequency it gave excellent results. In reply to Dr. Russell, he stated that the sensitivity of the galvanometer did vary slightly with the barometric pressure. In the ordinary differential equation the term giving the moment of the applied forces needed amending, and so also did the term for the damping couple. The complete equation was complex and there were difficulties in the way of getting an exact solution. The frequency of ordinary supply circuits was quite constant enough for accurate work. reply to Dr. Chree, he stated that the mirror was always symmetrically situated on the suspension. In A paper by Messrs. W. P. FULLER and H. GRACE on the "Effect of Temperature on the Hysteresis Loss in Iron in a Rotating Field" was read by Prof. MARCHANT. The rotating field was produced by means of two phase currents. One phase was connected to a coil of long rectangular section and of sufficient length to produce a uniform field within a radius of 2 cm. from the centre. The second phase was connected to a similar coil enclosing this one and causing a flux at right angles to it. The resultant field at the centre was uniformly rotating. An iron disc 4 cm. diam., o'027 cm. thick, was supported by a bifilar suspension and the torque measured by a mirror and the molecules within a magnetically stable group at high than at low temperatures. The authors' experiments might be regarded as adding strong confirmation to the molecular theory of magnetism. Prof. MARCHANT said the iron tested was obtained direct from the manufacturers and its previous thermal treatment was not known. A permeability curve had, however, been obtained. He expressed his interest in Dr. Eccles's remarks upon the bearing of the experiments on molecular theory of magnetism. A paper the "On a Method of Testing Photographic Shutters," by Messrs. A. CAMPBELL and T. SMITH, was read by Mr. SMITH. The authors described a simple and rapid method of testing the speeds and efficiencies of photographic shutters, with a maximum error of o'0001 second at the highest A vibrating beam of light falling through a speeds. narrow slit on to a moving plate serves to measure the time. This beam is obtained by reflecting the light of a Nernst lamp from the mirror (area 50 sq. mm.) of a vibration galvanometer actuated by a current of fixed frequency (say 100 or 500 vibrations per second) obtained from a microphone hummer. The use of the vibration galvanometer, in which the amplitude is enormously increased by resonance, greatly facilitates the measurements. When the total duration of exposure only is required, the vibrating beam of light is passed through the shutter, tracing a sine curve on the moving plate. The duration of exposure is immediately found by counting the number of ripples recorded on the plate. Ten records of the various speeds of a shutter can be taken side by side on one 5" x 4" plate in one minute. When the efficiency in addition to the duration of exposure is required, the method adopted is essentially that of Sir Wm. Abney, but the time measurements are made with the vibrating beam of light instead of a screen. The sine-curve now extends over the length of the plate and serves as a continuous time record, and is to be preferred to any intermittent method of measuring the time. A slit is placed in a diameter of the shutter-opening as close to the shutter leaves as possible, and an image of a line source of light is made to fill this slit. By means of a concave mirror an image of this slit is formed on the plate by the side of the vibrating beam of light. As the shutter opens the length of the slit through which light can reach the plate increases, and the record on the plate gives the length of the slit which is opened at every instant of time. Measurements are then taken of the area of the shutter aperture corresponding to a number of lengths of the slitopening. Combining these records the area of the shutter aperture at every instant of the exposure is obtained, and by integrating this area with respect to time the equivalent exposure at full aperture and the efficiency are cal culated. Mr. BAKER expressed his interest in the method, which he said was the most satisfactory yet produced. It was difficult to say exactly what to call exposure. In photographing moving objects it was advisable to use as the effective time the time during which the central eight tenths of the shutter was open. Mr. DUDDELL said the method was an ingenious one for determining the efficiencies of shutters. He suggested that by using an arc it might be possible to reduce the size of the mirror and thus work at higher frequencies. Instead of using a slit it might be better to use a short focus cylindrical lens. Mr. CAMPBELL, referring to Mr. Duddell's remarks, said that with a Nernst lamp it was possible to obtain high frequency curves showing very little tendency to tail off. | phenol hydroxyls, and in the molecule of which there are several nitro-groups, give considerable quantities of hydrocyanic acid when their aqueous solutions are boiled with ammonium persulphate. This phenomenon may be explained by supposing that the nitro-compounds yield isonitro derivatives, that the oxygen atom migrates from the nitrogen to the neighbouring carbon, giving a quinone, which is then oxidised with the formation of HCN. MISCELLANEOUS. Royal Institution.-A General Monthly Meeting of the Members of the Royal Institution was held on the 7th inst., Sir James Crichton-Browne, Treasurer and ViceSteeves were elected members. President in the Chair. Mr. A. E. Price and Dr. G. W. Faraday Society.-On Tuesday next, June 15, at p.m., in the Library of the Institution of Electrical Engineers, Mr. E. R. Taylor, Chairman of the Conservation Committee of the American Electrochemical Society, will deliver an Address, illustrated with lantern slides, on "The National and International Conservation of Water or Power." Seventh International Congress of Applied Chemisftry.-We have received from the Dover Street Studios a set of fourteen proofs of groups of the various Sections, taken on the steps of the Royal College of Science on the morning of the last day of the Congress. The portraits are more than usually successful. Each separate group does not contain too many individuals, and the heads therefore are sufficiently large to make them valuable as separate likenesses, as well as interesting as forming parts CHEMICAL NOTICES FROM FOREIGN of a group of workers in the same domain of applied SOURCES. Comptes Rendus Hebdomadaires des Séances de l'Académie des Sciences. Vol. cxlviii., No. 17, April 26, 1909. Cuprous Sulphate. - A. Recoura. By double decomposition between cuprous oxide and neutral methyl sulphate, cuprous sulphate is formed, Cu2O+ SO(CH3)2 = Cu2SO4 + (CH3)2O. When all the oxide has been converted into sulphate, the excess of methyl sulphate may transform the cuprous into cupric salt, but this reaction only occurs when the first is com. pleted, and it is easy to guard against it. Cuprous sulphate is a greyish white powder, which is absolutely unaltered in dry air. Water decomposes it into cupric sulphate and copper with disengagement of 21 cals., and this explains the difficulty of isolating the salt. Researches on Magnesium Derivatives of Bromides of Xylyls.-P. Carré.-The action of magnesium on ethereal solutions of bromides of xylyls gives chiefly ditolylethanes. The proportion of magnesium compound formed is much less than in the case of benzyl chloride. The bromide of metaxylyl, however, gives an appreciable amount of magnesium compound, the condensation of which with formaldehyde yields metatolylethyl alcohol, C6H4(CH3)1(CH2-CH2OH)3. With acetic aldehyde and acetone the alcohols formed are science. We understand the complete set is to be published in the form of an album. NOTES AND QUERIES. Our Notes and Queries column was opened for the purpose of giving and obtaining information likely to be of use to our readers generally. We cannot undertake to let this column be the means of transmitting merely private information, or such trade notices as should legitimately come in the advertisement columns. Estimation of Manganese.-What is the function of the silver nitrate in the Walters process for colorimetric determination of manganese (CHEMICAL NEWS, lxxxiv., 239) ?—J. WILLIAMS. MEETINGS FOR THE WEEK TUESDAY, 15th.-Faraday Society, 8. "The National and International Conservation of Water for Power," by E. R. Taylor. "Formation of Silicon Sulphide in the Desulphurisation of Iron," by W. Fielding. "Study of Electric Furnaces as applied to the Manufacture of Iron and Steel," by C. A. Keller. "Automatically Circulating Furnaces of the Gin Type for the Electrical Production of Steel," by G. Gin. WEDNESDAY, THURSDAY, 16th.-Microscopical, 8. Exhibition of the better-known Tropical Parasites, by Dr. J. A. Braxton Hicks. 17th.-Chemical, 8.30. "Carbonate of Copper and the Cupricarbonates," by S. P. U. Pickering. "Isoquinoline Derivatives-Part I., Oxidation of Laudanosine," by F. L. Pyman. "Colour and Constitution of Azo-compounds," by J. T. Hewitt and W. Thomas. "Isoiminazolone," by H. J. H. Fenton and W. A. R. Wilks. "Homologues of Furfural," by H. J. H. Fenton and F. Robinson. "Studies of Dynamic IsomerismPart IX., Relationship between Absorption Spectra and Isomeric Change-Absorption Spectra of Sulphonic Derivatives of Camphor," by T. M. Lowry and C. H. Desch. "Relation between the Strength of Acids and Bases and the Quantitative Distribution of Affinity in the Molecule," by B. Flürscheim. "Oxidation of Hydroxy-derivatives of Benzaldehyde and Acetophenone," by H. D. Dakin. "Intramolecular Re-arrangement of Diphenylamine-ortho-sulphoxides," by E. de B. Barnett and S. Smiles. FRIDAY, 18th.-Royal Institution, 9. "A Recent Visit to the Panama Canal," by A. H. Savage Landor. CHEMICAL NEWS, Advertisements. PATENT H2S APPARATUS (Crawford's System). NO CLOCCING OF TUBES. NO LEAKY JOINTS. 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All kinds of Platinum scrap bought Pure and Commercial. CHEMICALS, For Scientific and Technical purposes. Specialities: ETHERS, CHLOROFORM. or cash or taken in exchange for new.-DERBY and CO., Ltd., DOLGLASE & CO.. Tyne Vale Chemical Works, Skinnerburn-rd., 44, Clerkenwell Road, London, E.C. PORCELAIN ད NEWCASTLE-ON-TYNE. SILICATES OF SODA AND POTASH. IN THE STATE OF SOLUBLE GLASS OR IN CONCENTRATED SOLUTION. OLDEST and MOST RELIABLE MAKE. WILLIAM GOSSAGE & SONS, Ltd., Soap Works, Widnes. HALDENWANGER Can be obtained from all businesses which deal in Chemical Apparatus. London: Printed and Published for the Proprietor by EDWIN JOHN DAVEY, at the Office, 16, Newcastle Street Farringdon Street, E.C. June 11, 1909 |