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FORMULAS FOR GLASS MANUFACTURE. THE
HE Institute of Chemistry has sent us an account of the work of the Glass Research Committee appointed by the council of the institute in October last to conduct investigations with the view of arriving at suitable formulas for laboratory glassware, miners' lamp-glasses, combustion tubing, resistant glass for pharmaceutical products, glass for X-ray bulbs, etc. The main part of the report is here reprinted, and is of particular interest at the present time. Copies of the formulas can be obtained from the secretary, Institute of Chemistry, 30 Russell Square, W.C.
Since October, 1914, the research has been continued uninterruptedly, the chief aims being :-(i) to produce working formulas for all glasses used in laboratory work, and (ii) to ascertain the influence of various ingredients on the physical and chemical properties of glasses. The work was extended to include glass for miners' lamp-glasses, at the suggestion of the Home Office; and also glass for ampoules, to meet the needs of wholesale pharmaceutical chemists engaged in the production of army medical requirements. The committee also examined and reported on samples of British and French laboratory glassware, produced since the beginning of the war, a number of the specimens being made from formulas similar to, and in some cases almost identical with, those recommended by the committee.
The committee has had before it many specimens of glasses used for various purposes, of which analyses have been made by Mr. Bertram Blount, Mr. W. C. Hancock, and Mr. Otto Hehner. It has been found, however, that mixtures prepared in accordance with the analytical results were not always satisfactory; but the analyses were helpful in suggesting synthetic experiments, and during recent investigations some intricate analyses made by Mr. G. J. Alderton under the supervision of Mr. Blount have proved especially valuable. Apart from the analyses, the work has been almost entirely carried on at King's College by Prof. Herbert Jackson and Mr. T. R. Merton, and by the former at his own house. The work has involved a careful study of the chemistry of silicates, aluminates, borates, etc., in their relation to the manufacture of glasses.
Up to the present time, the research committee has reported eleven formulas for glasses for various purposes based on the results of about 400 experimental melts on a scale large enough for drawing rods and blowing small vessels. In addition, a very great number of experiments have been made in order to study the influence of the various constituents employed. No formula has been issued without submitting the specimens made to rigorous tests to prove their suitability for the purposes for which they are intended. Moreover, by varying the experimental working conditions, it can be said with reasonable confidence that the mixtures will prove equally satisfactory under the actual working conditions of a glass furnace. The question of workable temperatures has been carefully considered, and, so far as it is possible to judge, the melts on a small scale indicate that even better results will be obtained on the industrial scale. This view has been justified by the samples already received from manufacturers who have tried some of the formulas.
In deciding the formulas it has been found necessary to direct special attention to the proportions of basic and acidic substances in respect of the action of glass mixtures on clay crucibles during fusion, and it has been shown by careful investigation that the formulas proposed give melts in which the influence of the in
Alumina (Al,O1) 1.0 Calcium carbonate 0.6 Arsenious oxide
(As,O,) Antimony oxide (Sb,O,)
These glasses do not lose their easy-working qualities after repeated heating and blowing, and are plastic over a long range of temperature. They require a temperature of at least 1400-1500° C. for complete
A colourless and fusible glass withstanding rapid incorporation of the ingredients in order to obtain that changes of temperature exceptionally well.
A glass almost identical in its general behaviour with Jena resistance glass; withstands changes of temperature well, but, like Jena, is not suitable for working before the blowpipe. It darkens and tends to devitrify; operations-such, for instance, as sealing side tubes into flasks-are difficult, if permanent and neat joints are required.
Formula No. 3, recommended for pharmaceutical purposes, ampoules, etc., may be substituted for the resistance glass with advantage, as the ampoule glass lends itself very well to blowpipe work, and is also especially resistant chemically.
This glass is capable of withstanding high temperatures and rapid changes of temperature; works well before the blowpipe, and is free from the chief defect of Jena glass-namely, the readiness with which it becomes cloudy, and finally quite opaque after prolonged use.
By slight modifications of this formula, almost any degree of hardness can be obtained.
In formulas (8) and (9) substances such as magnesia (MgO) and zinc oxide (ZnO) can be added in the form of carbonates if the actual percentages of MgO and ZnO respectively present in the carbonates are known.
homogeneity which is necessary for resistance to rapid changes of temperature and ease of working before the blowpipe.
No. (10), containing potassium nitrate, is considered the better of the two, and is more easily incorporated.
The committee considers that the formulas obtained and the work done on the various glasses justify it in the opinion that there is now information available for the manufacture of all the important glasses used in the laboratory and for industrial purposes, which have hitherto been mainly obtained from abroad.
UNIVERSITY AND EDUCATIONAL
LONDON.-Prof. T. G. Brodie, professor of physiology in the University of Toronto, will deliver a course of four lectures on "The Gases of the Blood" at King's College, London, on May 31, June 2, 7, and 9. These lectures take the place of those previously announced; they are free to medical students, to internal students of the University, and to medical men on presentation of their cards.
MR. A. G. R. FOULERTON has been appointed lecturer in public health at the London (Royal Free Hospital) School of Medicine for Women, in succession to Prof. W. J. Simpson, resigned.
THE Education Committee of the County Council of the West Riding of Yorkshire has arranged a summer vacation course for teachers, which is to be held at Bingley Training College from August 4 to 18 next. Four evening lectures will be given during the course, including one by Mr. Mackinder on how much geography and history can be taught within the limits of the elementary school. The general course makes provision among numerous other subjects for lectures on the teaching of informal domestic work in schools, and the special courses include lectures on animal and plant life. The primary object of the courses is to increase the educational spirit and efficiency of persons teaching in the West Riding, and to enable them to supplement their knowledge of the various subjects, and of the most approved methods of teaching them. All particulars of the course, including time-tables, are given in the "Bingley Vacation Course Syllabus," copies of which may be obtained on application to the Education Department, County Hall, Wakefield.
ON March 6, Lord Hardinge, Viceroy of India, presided over the annual convocation of Calcutta University, and delivered an address in his capacity of Chancellor of the University. The address is printed in the issue of the Pioneer Mail for March 12. Chancellor referred to the increased interest which has arisen in Indian universities in the teaching of science subjects. University inspection combined with an ordered procedure in affiliation has considerably raised the standard of instruction in the colleges. Some of the laboratories attached to these institutions can now compare favourably with any in the world. The The teaching staffs have been strengthened.
advanced students produce papers dealing with subjects of research which are accepted by leading scientific journals in Europe. In the past years the Government of India has contributed generously to the capital requirement of the University of Calcutta, which also draws an annual sum, the capitalised value of which is 36 lakhs, and generous gifts have been received recently from the late Sir Taraknath Palit and Dr. Rashbehari Ghosh. In Bombay the contributions of few public-minded citizens to the proposed Royal Institute of Science have totalled nearly 25 lakhs, while Sir Chinubhai Madhav Lal has endowed the Institute of Science of Ahmedabad with six lakhs, giving a further two lakhs to the Gujerat College, with which it is associated. Lord Hardinge also dealt with the question of university buildings and libraries. The universities of India have recently made laudable efforts, which have been substantially aided by the Government, to provide for themselves local habitations in the shape of buildings befitting their dignity, and libraries where their alumni may learn the use of books and the methods of investigation and research which collections of books alone make possible. Calcutta has not been behindhand. Thanks to the generosity of the Maharaja of Darbhanga, the University is now possessed of a handsome library. The students of the Law College are accommodated in a hostel towards which the Government contributed three lakhs. The Government has also
made a grant of eight lakhs for the purchase of a valuable site which abuts on the University buildings, and the acquisition of which should permit of further extension.
SOCIETIES AND ACADEMIES.
Physical Society, March 26.—Dr. A. Russell, vicepresident, in the chair.-Prof. A. W. Porter and F. Simeon The change of thermal conductivity with fusion. The change in question was determined for mercury and for sodium by finding the temperatures at different points of a cylinder of the metal contained in a glass tube. The ends of the cylinder were maintained at such temperatures that the metal was liquid half-way down its length, the remaining part being solid. The temperatures were taken by means of thermo-electric junctions inserted in narrow tubular depressions which had been formed in the glass tube by forcing a knitting needle down into the locally heated glass. The ratio of the thermal conductivity for solid and liquid was estimated from the slope of tangents drawn to the temperature-curve on each side of the melting point. The values of these ratios are of the same order as the ratio of the corresponding | values of the electrical conductivities. The mean value for mercury is 3'91, and for sodium 1.31.-Dr. J. A. Fleming: An instrument for the optical delineation and projection of physical curves such as hysteresis, resonance, and characteristic curves. This instrument is designed for projecting on to a screen or photographing on a plate such curves as magnetic hysteresis, resonance, or characteristic curves which can be performed slowly, or are non-periodic or nonrepetitive. Dr. P. Phillips and J. Rose Innes: The stability of some liquid films. The authors give a simple method of calculating the equilibrium form of a thin film which is a surface of revolution. They then consider the stability for certain kinds of displacement of three classes of such films, viz., the sphere, the cylinder and the catenoid. The mathematics used is quite elementary throughout and the
treatment is rigorous.-Prof. A. W. Porter and E. Talbot Paris: A demonstration of the green-flash of the setting of an artificial sun. A large disc of card mounted so that it can be slowly rotated has a hole, 1 in. in diameter, cut in it about 2 in. from the periphery. This is covered with red gelatine films, and is illuminated from behind so as to form an artificial The front of the disc is covered with white Bristol board and is moderately illuminated by a lamp in front. This sun is viewed through a rectangular aperture (4 in. wide) in a blackened board, the lower edge of the aperture serving as the horion. When the disc is rotated the artificial sun sets and green afterimages are obtained of characters varying according to the amount that the eye has been exposed to the bright sun. If the sun is not viewed until immediately before the complete setting the after-image represents simply the disappearing segment to which it is due. The authors claim that this phenomenon is what is often described as the green-flash at sunset, though they are ready to admit that other (but probably rarer) phenomena also go under the same name.
Literary and Philosophical Society, March 23.-Mr. F. Nicholson, president, in the chair.-T. A. Coward : A note on the behaviour of a blackbird-a problem in The author referred to the mental development. habit of certain birds-individual, not specific-which when stirred by spring rivalry will fight with their own reflections as seen in windows, and spoke, in particular, of a male blackbird which for more than a month has been daily assaulting its own image in a particular window. A blackbird, presumably the same, behaved in a similar way at the same window all through last spring. Attention was directed to the psychological problem presented by a bird with an excellent memory but without any apparent power of learning by experience. The recollection of this visionary antagonist was stimulated by the seasonal sexual activity and died down with the normal waning of this force.A. W. Rymer Roberts: Two cases of parallelism in the Aphida. Parallel series of aphids may co-exist on the same or on different plants, having the same ancestry but differing in habits and sometimes also in form. The phenomenon was first brought in prominence by Cholodkovsky's recent researches on Chermes. Though there exists some doubt, in the light of more recent research, whether the instances principally relied upon are not those of distinct biological species, other instances have been discovered of as many as four parallel forms being descended from the winter-form on the secondary host-plant in certain species of Chermes. Parallelism exists also in other groups, as in the Pemphiginæ, two instances observed being (1) Thecabius affinis, a species migrating between poplars and Ranunculus, and (2) Hamamelistes tullgreni, so far only found on birch. T. affinis has been found continuing to live over the winter on Ranunculus after the migrating individuals have returned to the poplar. H. tullgreni has been observed in England for the first time during the past year. Certain of its forms resemble scale insects. It has so far only been found upon birch, but winged individuals fly from that to some other plant, leaving wingless individuals to continue the race on the birch, both being descended from a single ancestress by parthenogenesis.
Royal Society, March 1.- -Prof. Hudson Beare, vicepresident, in the chair.-H. Levy: The resistance of a fluid to a body moving through it. In this paper
it was shown that trails of vortices following in the wake of a body moving through a fluid did not form a stable system, so that the theory recently advanced by Karman, which was based upon a suggestion made originally by Kelvin, did not seem to be tenable. The paper also contained an interesting development of the method of finding the stream lines with certain definable forms of boundary.-F. D. Miles: The electrical conductivity of aqueous hydrochloric acid, saturated with sodium chloride; and on a new form of conductivity cell. Within the range of concentration (15 to 27 per cent. of hydrogen chloride) the specific conductivity is lowered by saturation with salt. The salt-saturated acid of maximum conductivity was prepared by adding salt to a solution containing 21.9 per cent. of hydrogen chloride, whereas the best conducting solution of hydrogen chloride alone contains only 19.1 per cent. of that substance. The conductivity cell described was specially suitable for solutions which are saturated or contain volatile constituents.-F. D. Miles: The reaction between sodamide and hydrogen. At temperatures near 250° C. these substances react according to the formula, NaNH,+H,=NaH+NH.
March 15.-Prof. Bower, vice-president, in the chair. -Dr. J. H. Ashworth: The larvæ of Lingula and Pelagodiscus. Sixteen larvæ of Lingula anatina were taken by him last year in the surface waters of the southern part of the Red Sea, and one in the Indian Ocean about 4° south of Colombo. The latter is noteworthy because of the depth of water (2200 fathoms) in the locality where the larva was taken. The larvæ varied from 0.5 to 1.6 mm. in length. Descriptions were given of the alimentary canal, calomoducts (nephridia), and statocysts, and of the changes in shape of the shell valves as growth proceeds. An account was also given of the anatomy of the larva of Pelagodiscus (Discinisca) atlanticus, based on six specimens, about 0.4 mm. in length, which were taken in October last a few miles west of Cape Cormorin in water of 40 fathoms. Adult specimens of this Brachiopod have almost entirely been recorded from deep water. Blochmann has denied the presence of statocysts in both Lingula and Pelagodiscus, but these organs were certainly present in both genera.-C. Cochrane: The reflective power of pigments in the ultra-violet. The diffuse reflection from the prepared strip of pigment, which was illuminated by a complete iron-arc spectrum, was photographed, a similar photograph of the reflection from a contiguous strip of white cardboard being simultaneously taken as a standard of comparison. More than thirty different pigments were experimented with, and of these the greater number showed selective reflection in the higher ultra-violet. There were, however, marked exceptions, such as Chinese white, the reflective power of which rapidly diminished as the wave-lengths became shorter.-Dr. W. T. Gordon: Archæocyathinæ collected by the Scottish National Antarctic Expedition. The specimens were obtained in a block of limestone dredged in the Weddell Sea, and associated with them were remains of calcareous algæ and sponges. The Archæocyathinæ can be grouped under the genera Archæocyathus, Spirocyathus, Coscinocyathus, Syringocnema, and Protopharetra. The fauna shows striking similarity with that described by Taylor from the Cambrian rocks of South Australia.
Academy of Sciences, April 6.-M. Ed. Perrier in the chair.-G. Bigourdan: The instrumental undulations of images; their daily and annual variation and their
relation with the general state of the atmosphere. A discussion of the causes and means of elimination of the irregular movements of the focal images of stars.-Paul Appell: The approximate inversion of certain real integrals, and on the extension of Kepler's equation and Bessel's functions.-L. E. Bertin Calculation of the increase of velocity or of range of submarines resulting from increase of their dimensions. Data furnished by ordinary vessels are
not directly applicable to submarines. It would appear that the maximum speed and range will be reached for a submarine having a displacement at the surface of 1000 tons.-Maurice Hamy: Radiography in the hospital at the Institute. Radiographs of all the wounded are made as they enter the hospital in the same attitude on two distinct plates, the bulb being moved a distance of 7 cm. The negatives, examined in a specially constructed stereoscope, show the position of the metallic fragment or of which the damaged bone in relief, by means operation is much simplified.-M. Guignard: The formation of pollen.-J. Bosler: The rotation of the solar corona. Measurements of the red line of wavelength 63744 on the east and west borders gave by the application of the Doppler-Fizeau principle a tangential velocity of 3.7 kilometres per second, with a possible error of 25 to 30 per cent. This agrees well with the determination of W. W. Campbell, who by applying the same method to the green line 5303 obtained a velocity of 3'1 kilometres per second. Hence the corona moves in the same sense as the direction of movement of the sun, and apparently with a higher velocity.-H. Deslandres: Remarks on the preceding communication and on problems connected with the rotation of the solar corona. study of the corona throws light on the important question of a corpuscular radiation emitted by the sun and received by the earth, but increase of knowledge in this direction must necessarily be slow, since the corona is only observable during eclipses.-Daniel Berthelot The temperature-coefficient of photochemical reactions. For the changes studied, the decomposition of lævulose and the decomposition of a mixture of oxalic acid and ferric chloride the rate of photochemical change is increased by a rise of temperature, but the coefficient is very much smaller than that of an ordinary chemical change.-Henri Coupin : The resistance of marine bacteria to the action of salt. Marine bacteria have tolerance for a considerable range in the proportion of salt in the water in which they develop, as they can support 8 per cent., and are content with as little as 0-3 to o'2 per cent. They adapt themselves better to proportions lower than the normal sea-water salt-content than to more concentrated solutions.-C. Sauvageau: The development and the biology of Saccorhiza bulbosa.-J. Bergonié: The detection and localisation of magnetic projectiles by an electromagnet actuated by an alternating current. The vibration of the flesh immediately over the metallic fragment gives an accurate indication of its position. Details are appended of several operations successfully carried out by this means. MM. Belot and Maxime Ménard: The use of the Coolidge tube in the medico-surgical applications. of the X-rays. The Coolidge tube is based on the discharge of independent electrons and details are given of a pattern made in France by Pilon. advantages obtained, as compared with the ordinary tube, are the regularity in working, the long period of regular working, the possibility of regulating the tube without modifying the vacuum, the fixed point of impact on the kathode, and the homogeneity of the bundle of X-rays.-Miramond de Laroquette and Gaston Lemaire: Tables of the coefficients of magni
British Museum (Natural History). Report on Cetacea Stranded on the British Coasts during 1914. Pp. 16. (London: British Museum (Natural History); Longmans and Co.) 1s. 6d.
British Museum (Natural History). British Antarctic (Terra Nova) Expedition, 1910. Natural History Report. Zoology. Vol. i., No. 2. Natural History of the Adelie Penguin. By Staff-Surgeon G. Murray Levick. Pp. 55-84+plates i-xxi. (London: British Museum (Natural History); Longmans and Co.) 5s. Memoir on the Economic Geology of Navanagar State in the Province of Kathiawar, India. By E. H. Adye. Pp. xxvi+262. (Bombay: Thacker and Co., Ltd.)
The Manchester Museum. Museum Handbooks : The Stela of Sebek-khu. By T. E. Peet. Pp. 21. (Manchester University Press.) 25.
The Plateau Peoples of South America. By A. A. Adams. Pp. 134. (London: G. Routledge and Sons, Ltd.) 3s. 6d. net.
An Amateur's Introduction to Crystallography. By Sir W. P. Beale. Pp. vii+220. (London: Longmans and Co.) 4s. 6d. net.
The Panama Canal. By R. E. Bakenhus, Capt. H. S. Knapp, and Dr. E. R. Johnson. Pp. xi+257. (New York: J. Wiley and Sons, Inc.; London: Chapman and Hall, Ltd.) 10s. 6d. net.
Heating and Ventilating Buildings. By Prof. R. C. Carpenter. Sixth edition. Pp. xiv+598. (New York: J. Wiley and Sons, Inc.: London: Chapman and Hall, Ltd.) 15s. net.
DIARY OF SOCIETIES.
THURSDAY, APRIL 15.
ROYAL INSTITUTION, at 3.-The System of the Stars: Star Colour and its Significance: Prof. A. S. Eddington.
INSTITUTION OF ELECTRICAL ENGINEERS, at 8.-The Power Supply of the Central Mining-Rand Mines Group: J. H. Rider.
LINNEAN SOCIETY. at 5.-Experiments and Observations bearing on the Interpretation of Form and Coloration in Plants and Animals: C. F. M. Swynnerton.
INSTITUTION OF MINING AND METALLURGY, at 8.-The Precipitating Action of Carbon in Contact with Auriferous Cyanide Solutions: W. R. Feldtmann.-Cvaniding of Gold-Silver Ores at Waihi Grand Junction: N. Carless.-The Effect of Mineralised Waters in Cyanide Plants: T. B. Stevens and W. S. Bradley.
THURSDAY, APRIL 22.
ROYAL SOCIETY, at 4.30.-Probable Papers: Deep Water Waves, Progressive or Stationary, to the Third Order of Approximation: Lord Rayleigh.-A Chemically Active Modification of Nitrogen, produced by the Electric Discharge. VI. Hon. R. J. Strutt.-The Difference between the Magnetic Diurnal Variations on Ordinary and Quiet Days at Kew Observatory: Dr. C. Chree. -The Effects of Different Gases on the Electron Emission from Glowing Solids: F. Horton.-Heats of Dilution of Concentrated Solutions: W. S. Tucker.-The Origin of the “4686' Series: T. R. Merton.
ROYAL INSTITUTION, at 3.-The System of the Stars: The Stellar System in Motion Prof. A. S. Eddington.
Changes of Relative Levels of Land and Sea.
Formulas for Glass Manufacture
Books Received Diary of Societies
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