152 British Association.-Prof. Ayrton's Address. ADDRESS TO THE MATHEMATICAL AND PHYSICAL SECTION OF THE BRITISH ASSOCIATION. BRISTOL, 1898. By Professor W. E. AYRTON, F.R.S., President of the Section. A YEAR ago Section A was charmed with a Presidential Address on the poetry of mathematics, and if, amongst those who entered the Physics lecture theatre at Toronto on that occasion, there were any who had a preconceived notion that mathematics was a hard, dry, repellent type of study, they must, after hearing Professor Forsyth's eloquent vindication of its charms, have departed convinced that mathematics resembled music in being a branch of the fine arts. Such an address, however, cannot but leave a feeling of regret amongst those of us who engulfed in the whirl of the practical science of the day, sigh for the leisure and the quiet which are necessary for the worship of abstract mathematical truth, while the vain effort to follow in the footsteps of one gifted with such winning eloquence fills me with hopeless despair. Section A this year is very fortunate in having its meetings associated with those of an "International Conference on Terrestrial Magnetism and Atmospheric Electricity," which is attended by the members of the "Permanent Committee for Terrestrial Magnetism and Atmospheric Electricity" of the "International Meteorological Conference." It has been arranged that this Permanent Committee, of which Professor Rücker is the President, shall form part of the General Committee of Section A, and also shall act as the Committee of the International Conference, which will itself constitute a separate department of Section A. For the purpose, how. ever, of preparing a Report to the International Meteorological Conference, and for similar business, this Permanent Committee will act independently of the British Association. My first duty to-day, therefore, consists in expressing the honour and the very great pleasure which I feel in bidding you, members of the International Conference, most heartily welcome. Among the various subjects which it is probable that the Conference may desire to discuss, there is one to which I will briefly refer, as I am able to do so in a triple capacity. The earth is an object of much importance, alike to the terrestrial magnetician, the telegraph electrician, and the tramway engineer; but while the first aims at observing its magnetism, and the second rejoices in the absence of the earth currents which interfere with the sending of messages, the third seems bent on converting our maps of lines of force into maps of lines of tramway. It might, therefore, seem as if electric traction-undoubtedly a great boon to the people, and one that has already effected important social developments in America and on the continent of Europe-were destined in time to annihilate magnetic observatories near towns, and even to seriously interfere with existing telegraph and telephone systems. Already the principle of the survival of the fittest is quoted by some electrical engineers, who declare that if magnetic observatories are crippled through the introduction of electric tramways, then so much the worse for the observatories. And I fear that my professional brethren only look at me askance for allowing my devotion to the practical applications of electricity to be tainted with a keen interest in that excessively small, but none the less extremely wonderful, magnetic force which controls our compass needles. But this interest emboldens me to ask again, Can the system of electric traction that has already destroyed the two most important magnetic observatories in the United States and British North America be the best and the {CHEMICAL NEWS. Sept. 23, 1898. fittest to survive? Again, do we take such care, and spend such vast sums, in tending the weak and nursing the sick because we are convinced that they are the fittest to survive? May it not perhaps be because we have an inherent doubt about the justness of the survival of the strongest, or because even the strongest of us feels compelled to modestly confess his inability to pick out the fittest, that modern civilisation encourages not the destruction but the preservation of what has obvious weakness, on the chance that it may have unseen strength? When the electrical engineer feels himself full of pride at the greatness, the importance, and the power of his industry, and when he is inclined to think slightingly of the deflection of a little magnet compared with the whirl of his 1000 horse-power dynamo, let him go and visit a certain dark store-room near the entrance hall of the Royal Institution, and, while he looks at some little coils there, ponder on the blaze of light that has been shed over the whole world from the dimly-lighted cupboard in which those dusty coils now lie. Then he may realise that while the earth as a magnet has endured for all time, the earth as a tramway conductor may at no distant date be relegated to the class of temporary makeshifts, and that the raids of the feudal baron into the agricultural fields of his neighbours were not more barbarous than the alarms and excursions of the tramway engineer into the magnetic fields of his friends. A very important consideration in connection with the rapid development of physical inquiry is the possibility of extending our power of assimilating current physical knowledge. For so wide have grown the limits of each branch of physics that it has become necessary to resort to specialisation if we desire to widen further the region of the known. On the other hand, so interlinked are all sections of physics that this increase of specialisation is liable to hinder rather than assist advance of the highest order. An experimenter is, therefore, on the horns of a dilemma-on the one hand, if he desires to do much he must confine himself more or less to one line of physical research, while, on the other hand, to follow that line with full success requires a knowledge of the progress that is being made along all kindred lines. Already an investigator who is much engaged with research can hardly do more as regards scientific literature than read what he himself writes-soon he will not have time to do even that. Division of labour and co-operation have, therefore, become as important in scientific work as in other lines of human activity. Like bees, some must gather material from the flowers that are springing up in various fields of research, while others must hatch new ideas. But, unlike bees, all can be of the "worker" class, since the presence of drones is unnecessary in the scientific hive. Englishmen have long been at a disadvantage in not possessing any ready means of ascertaining what lines of physical inquiry were being pursued in foreign countries -or, indeed, even in their own. And, so far from making it easier to obtain this information, our countrymen have, I fear, until quite recently, been guilty of increasing the difficulty. For every college, every technical school in Great Britain-and their number will soon rival that of our villages-seems to feel it incumbent on itself to start a scientific society. And in accordance with the self-reliant character of our nation, each of these societies must be maintained in absolute independence of every other society, and its proceedings must be published separately, and in an entirely distinct form from those of any similar body. To keep abreast, then, with physical advance in our own country is distinctly difficult, while the impossibility of maintaining even a casual acquaintance with foreign scientific literature lays us open to a charge of international rudeness. There is, of course, the German Beiblätter, but the CHEMICAL NEWS, British Association.-Prof. Ayrton's Address. Anglo-Saxon race, which has spread itself over so vast a portion of the globe, is proverbially deficient in linguistic powers, and consequently, till quite recently, information that was accessible to our friends on the Continent was closed to many workers in Great Britain, America, and Australia. Influenced by these considerations the Physical Society of London, in 1895, embarked on the publication of abstracts from foreign papers on pure physics, and, as it was found that this enterprise was much appreciated, the question arose at the end of the following year, whether, instead of limiting the journals from which abstracts were made to those appearing in foreign countries, and the papers abstracted to those dealing only with pure physics, the abstracts might not with advantage be enlarged, so as to present a résumé of all that was published in all languages on physics and its applications. The first application of physics which it was thought should be included was electrical engineering, and so negotiations were opened with the Institution of Electrical Engineers. After much deliberation on the part of the representatives of the two societies, it was finally decided to start a monthly joint publication, under the management of a committee of seven, two of whom should represent the Institution of Electrical Engineers, two the Physical Society, and three the two societies jointly. Science Abstracts was the name selected for the periodical, and the first number appeared in January of this year. A section is devoted to general physics, and a separate section to each of its branches; similarly a section is devoted to general electrical engineering, and a separate section to each of its more important subdivisions. The value of Science Abstracts is already recognised by the British Association as well as by the Institution of Civil Engineers, for those societies make a liberal contribution towards the expenses of publication, for which the Physical Society and the Institution of Electrical Engineers are responsible. At no distant date it is thought that other bodies may co-operate with us, and we have hopes that finally the scheme may be supported by the scientific societies of many Anglo-Saxon countries. For our aim is to produce, in a single journal, a monthly record in English of the most important literature appearing in all languages on physics and its many applications. This is the programme-a far wider one, be it observed, than that of the Beiblätter-which we sanguinely hope our young infant Science Abstracts will grow to carry out. The saving of time and trouble that will be effected by the publication of such a journal can hardly be overestimated, and the relief experienced in turning to a single periodical for knowledge that could hitherto be obtained solely by going through innumerable scientific newspapers, in many different languages, can only be compared with the sensation of rousing from a distracting and entangled dream to the peaceful order of wakeful reality. I therefore take this opportunity of urging on the members of the British Association the importance of the service which they can individually render to science by helping on an enterprise that has been started solely in its aid, and not for commercial purposes. The greatness of the debt owed by industry to pure science is often impressed on us, and it is pointed out that the comparatively small encouragement given by our nation to the development of pure science is wholly incommensurate with the gratitude which it ought to feel for the commercial benefits science has enabled it to reach. This is undoubtedly true, and no one appreciates more fully than myself how much commerce is indebted to those whose researches have brought them-it may be fame, but certainly nothing else. The world, however, appears to regard as equitable the division of reward which metes out tardy approbation to the discoverer for devising some new principle, a modicum of the world's 153 goods to the inventor for showing how this principle can Again, in the "History of the Royal Society at the The analytical investigation of the motion of one body round an attracting centre, when disturbed by the attraction of another, was attacked independently by Clairault, D'Alembert, and Euler, because the construction of lunar tables had such a practical importance, and because large money prizes were offered for their accurate determination. The gambling table gave us the whole Theory of Probability, Bernoulli's and Euler's theorems, and the first demonstration of the binomial theorem, while a request made to Montmort to determine the advantage to the banker in the game of "pharaon" started him on the consideration of how counters could be thrown, and so led him to prove the multinomial and various other algebraical theorems. Lastly, may not the gambler take some credit to himself for the first suggestion of the method of least squares, and the first discussion of the integration of partial differential equations with finite differences contained in Laplace's famous "Théorie Analytique des Probabilités "?" The question asked Rankine by James R. Napier regarding the horse-power which would be necessary to propel, at a given rate, a vessel which Napier was about to build, resulted in the many theoretical investigations carried out by Rankine on water lines, skin-friction, stream lines, &c. For, as Professor Tait has said, "Rankine, by his education as a practical engineer, was eminently qualified to recognise the problems of which the solution is required in practice; but the large scope of his mind would not allow him to be content with giving merely the solution of those particular cases which most frequently occur in engineering as we now know it. His method invariably is to state the problem in a very general form, find the solution, and apply this solution to special cases." Helmholtz studied physiology because he desired to be a doctor, then physics because he found that he needed it for attacking physiological problems, and lastly mathematics as an aid to physical research. But I need not remind you that it is his splendid work in mathematics, physics, and physiology, and not his success in ministering to the sick, that has rendered his name immortal. Did not Kepler ask "How many would be able to make astronomy their business if men did not cherish the hope of reading the future in the skies?" And did he not 156 Luminosity produced by Striking Sugar. CHEMICAL NEWS, The immediate separation of cuprous oxide and evolution, when in use and afterwards, that the acid may not come of hydrogen, without formation of basic salt, which occurs at the commencement of the reaction, may be represented by the equation 2Mg+2CuSO4 + H2O=2MgSO4+Cu2O+H2. The action of the magnesium-copper couple has been proved to be too slow to explain the rapid escape of hy drogen, and if this were the origin of the hydrogen, its escape would not immediately follow the immersion of the magnesium. ON A CONVENIENT FORM OF DRYING TUBE.* A COMMON method of drying gases is to pass them through a wash-bottle containing sulphuric acid and then through a U-tube filled with fragments of pumice moistened with the same liquid. The number of corks and connections in contact with the corks; if too much acid is poured in, the bend becomes blocked by a plug of liquid; there is no means of telling when the acid has become less efficient by dilution; nor is it easy to re-charge the tube with fresh acid. The form of drying-tube shown avoids these defects. It is at once wash-bottle and drying-tube. It has one cork and stands upright; the pumice can be well drenched with sulphuric acid, the excess draining down and filling the lower part (through which the gas bubbles) to a convenient height; dilution announces itself, and the acid is easily renewed. The shape is that of a Gay-Lussac burette with a constriction about two inches from the bottom. A piece of pumice, large enough to block the constriction is first dropped in, and the tube is filled to near the top with small fragments of pumice. In charging with acid care is taken not to wet the upper part of the tube; next day the level of the acid in the lower part of the tube is marked with a strip of gummed paper. The small side tube which enters the large tube near the bottom is the inlet for gas; when the moisture absorbed has raised the level of the acid about 2 m.m. above the mark, the acid in the lower part is poured off through the small tube, and fresh acid is poured in through the pumice. The inlet and outlet tubes are made of the same height, so that a series of similar drying tubes may readily be joined together. ON THE LUMINOSITY PRODUCED BY By JOHN BURKE, M.A. WHEN two lumps of sugar are struck a flash is produced of a somewhat bluish white colour, but the light is instantaneous, and yet at the same time spreads into the sugar itself far beneath the struck surface. An almost continuous luminosity, however, has been produced by a hammer striking automatically the rim of a rapidly rotating wheel of sugar (obtained by cutting up a sugar-loaf into a number of discs); the wheels or discs being about an inch thick, so as to stand the violent hammering; the hammer, being of the nature of a pendulum about four feet in length, which was drawn aside by an electro-magnet and then let go. Curiously enough, if the impact is given when the wheel is stationary, so that only an impulse is given without rubbing, or if, on the other hand, the wheel is set spinning and the hammer is stationary and merely allowed to rub up against the wheel, the phenomenon is insignificantly small compared to that obtained when both rubbing and knocking take place together; that is, when the wheel and hammer are both working. The spectrum of the luminosity is confined to the more refrangible end of the spectrum, commencing somewhere about F, but it is difficult to say exactly. One difficulty in the way of observing the spectrumand still more of photographing it-is the rapid rate at which this sugar wears out; and to overcome this the whole apparatus is fixed on rollers moved slowly along at a suitable rate to compensate for the change in the position of the sparks which would otherwise take place, and by this means the sparks or flashes of luminosity, which appear almost continuous, are made to take place always along the axis of the collimator of the spectroscope. The fact that the less refrangible part of the spectrum is absent shows undoubtedly that the luminosity cannot be due to the particles of sugar becoming red-hot or white. hot by the impacts, but seems to show that the light produced is due either to some change in the configuration of the crystals of sugar or to some sort of chemical action * Abstract of a Paper read before the British Association (Section A), Bristol Meeting, 1898. CHEMICAL NEWS, Sept. 23. 1898. Preparation and Properties of Hydride of Calcium. set up between the sugar and the surrounding air at the freshly formed surface. To test the latter hypothesis, the spark has been produced by dropping a lump of sugar in a tall receiver, and it was found that the colour and intensity of the flash were independent of the pressure of the air-between 76 c.m. and 2 c.m. And likewise when coal-gas was substituted for air it was also found that wetting the surface of the sugar did not alter the effect; and when two lumps of sugar were struck in water, the interesting result was obtained that the light was-so far as could be judged by merely looking at it-precisely similar to that obtained in air and coal-gas. The fact that the surrounding medium does not seem to affect either the colour or intensity of the luminosity suggests that the effect is not due to any influence of a chemical nature of the surrounding medium on the sugar, but favours the former hypothesis that the luminosity is due to the peculiar structure of the sugar itself. The experiments are being pursued further. 157 independence of body and base renders it possible to produce the furnace at a lower cost than usual and facilitates packing and transport, and it has the further advantage that the cracking which takes place with all internallyfired fire-clay furnaces is less than in those made in one piece. For roasting, heating platinum and other small crucibles, cupelling, scorifying, and general muffle work an extra door is supplied, through which a muffle passes. The second figure shows this appliance, the body of the furnace having been removed from the base to show the arrangement more clearly, and the small door which closes the muffle aperture being shown drawn aside. The back of the muffle rests on a removable block, as shown. This furnace, which is about 13 inches in length, is found to be suitable for all the ordinary work of a laboratory, the various improvements in its construction also greatly facilitating the work done with it. NEW LABORATORY GAS FURNACE. OUR illustrations show a new fireclay gas furnace manufactured by Messrs. J. J. Griffin and Sons, on lines suggested by Mr. G. T. Holloway, for use by assayers, &c., or for performing any of the furnace work required in a chemical laboratory. FIG. I. From the first illustration it will be seen that the furnace base extends forward beyond the body, and forms a convenient stand for hot crucibles, &c., and for the doors when they are drawn forward. The deep flanges on the doors serve as handles for moving them when the FIG. 2. furnace is in use, and also support them in position and render them reversible. The base and body are made in independent parts, so that either may be replaced at small cost, and the base may reversed when spoiled on one side by slags, &c. This THE PREPARATION AND PROPERTIES OF By HENRI MOISSAN. Preparation.-Pure crystallised calcium, prepared by the method we described in a previous communication (Comptes Rendus, cxxvi., p. 1753, June 20, 1898) is put into a nickel boat in a glass tube traversed by a current of pure dry hydrogen. The hydrogen is purified by being passed through two porcelain tubes at a red heat,-one filled with copper and the other with pure boron. It is then dried with fused potash and phosphoric acid, previously calcined in a current of oxygen. At the ordinary temperature calcium does not react on hydrogen. When the tube containing the nickel boat has been well swept by a rapid current of hydrogen, the end of the tube is sealed and the hydrogen is kept in it at a pressure of from 30 to 40 c.m. of water. The temperature of the boat containing the lime is then slowly raised, and when it reaches a dull red heat we can see it take fire in the atmosphere of hydrogen. The gas is absorbed with great rapidity, and we obtain, in place of the metal, a white substance, which is hydride of calcium. If we perform this experiment on 1 or 2 grms. of calcium it may be done in a glass tube, but the great disengagement of heat produced by this combination may give rise to the reduction of the glass by the alkaline earthy metal, producing black spots on the glass by the setting free of small quantities of silicon. When the reaction is carried out in nickel boats, as we have already described, it is advisable not to work on more than 5 or 6 grms. of material at a time, or else the temperature becomes too high, and we more frequently find a crystallised alloy of nickel and calcium at the line of contact with the metallic nickel. When we wish to get a higher return of this hydride we can easily do so by putting several boats containing calcium in the tube, so that the reaction will be performed successively. The metallic tube is then placed on a gas furnace with eight jets, and by using three boats we can easily work with 15 grms. of calcium. If the hydrogen contains nitrogen, we notice that the hydride takes a greyish yellow tint and gives off ammonia by its decomposition with water. Properties.-Hydride of calcium is a white body, and after fusion has a crystalline fracture. Examined under the microscope it appears in thin transparent layers, some of which are again covered by very small crystals. It does not perceptibly dissociate up to a temperature of 600° in vacuo. Its density taken in essence of turpentine is 17. 154 Extraction of the Companions of Argon and on Neon. {CHEMICAL NEWS, Sept. 23, 1898. warn those who objected to the degradation of mingling | gas was again liquefied and boiled off in six fractions. astrology with astronomy, to beware of "throwing away the The density of the lightest fraction was thus reduced to child with the dirty water of its bath"? Even now, may | 13:4, and it showed a spectrum rich in red, orange, and we not consider all the astronomical research work done yellow lines, differing totally from that of argon. On reat the Royal Observatory, Greenwich, as a by-product, | fractionating, the density was reduced further to 10·8; the since the Observatory is officially maintained merely for gas still contained a little nitrogen, on removing which the purposes of navigation? And are there not many of the density decreased to 9.76. This gas is no longer liqueus who feel assured that, since researches in pure physics fiable at the temperature of air boiling under a pressure and the elucidation of new physical facts must quite of about 10 m.m.; but if, after compression to two legitimately spring from routine standardising work, the atmospheres, the pressure was suddenly reduced to about most direct way-even now at the end of the nineteenth a quarter of an atmosphere, a slight mist was visible in century of securing for the country a National Physical the interior of the bulb. This gas must necessarily have Laboratory is to speed forward a Government standard-contained argon, the presence of which would obviously ising institute? increase its density; and in order to form some estimate Lastly, as you will find in Dr. Thorpe's fascinating of its true density, some estimate must be made of the "Life of Davy," it was the attempt to discover the relative amount of the argon. We have to consider a medicinal effect of gases at the Pneumatic Institution in mixture of neon, nitrogen, and argon, the two latter of this city that opened up to Davy the charm of scientific | which are capable, not merely of being liquefied, but of research. And, indeed, the Royal Institution itself, the being solidified without difficulty. Under atmospheric scientific home of Davy, Faraday, Tyndall, Rayleigh, and pressure nitrogen boils at 194°, and solidifies at -214°, Dewar, owes its origin to Romford's proposal" for forming and the boiling-point of argon is -187°, and the freezingin London by private subscription an establishment for point - 190°; the vapour-pressure of nitrogen is therefore feeding the poor and giving them useful employment.. considerably higher than that of argon. The mist proconnected with an institution for introducing and bringing duced on sudden expansion consisted of solid nitrogen forward into general use new inventions and improve and argon; and for want of better knowledge, assuming ments by which domestic comfort and economy may be the vapour-pressure of the mixture of nitrogen and argon promoted." to be the sum of the partial pressures of the two, it is obvious that that of argon would form but a small fraction of the whole. The vapour-pressure of argon was found experimentally to be 109 m.m. at the temperature of air boiling in as good a vacuum as could be produced by our pump; but as we have only to consider the partial pressure of the argon at a much lower temperature, we do not believe that the pressure of the argon can exceed 10 m.m. in the gas. This would correspond to a density for neon of 9.6. (To be continued). ON THE EXTRACTION OF THE COMPANIONS By WILLIAM RAMSAY, F.R.S., and MORRIS W. Travers. IN the Presidential Address to the Chemical Section of this Association, delivered last year at Toronto, it was pointed out that the densities of helium and argon being respectively 2 and 20 in round numbers, and the ratio of their specific heats being in each case 1'66, their atomic weights must be respectively 4 and 40. If the very probable assumption is made that they belong to the same group of elements, it appears almost certain on the basis of the Periodic Table that another element should exist, having an atomic weight higher than that of helium by about 16 units, and lower than that of argon by about 20. There is also room for elements of higher atomic weight than argon, belonging to the same series. The search for this element was described in last year's Address, and, it will be remembered, the results were negative. The ratio between the specific heat at constant pressure and constant volume was determined in the usual way for neon, and, as was to be expected, it approximates closely to the theoretical ratio, being 1'655. We there. fore conclude that, like helium and argon, the gas is monatomic. It may be remembered that the refractivity of helium compared with that of air is exceptionally low-viz., 01238. The lighter gas, hydrogen, has a refractivity of 0'4733. It was to be expected from the monatomic character and low density of neon that its refractivity should be also low; this expectation has been realised, for the number found is 0.3071. Argon, on the other hand, has a refractivity not differing much from that of air-viz., o'958. Since the sample of neon certainly contains a small amount of argon, its true refractivity is probably somewhat lower. Experiments will be carried out later to ascertain whether neon resembles helium in its too rapid rate of diffusion. Reading between the lines of the Address, an attentive critic might have noticed that no reference was made to the supposed homogeneity of argon. From speculations of Dr. Johnstone Stoney, it would follow that the atmoThe spectrum of neon is characterised by brilliant lines sphere of our planet might be expected to contain new in the red, the orange, and the yellow. The lines in the gases, if such exist at all, with densities higher than 8 or blue and violet are few, and comparatively inconspicuous. thereabouts. Dr. Stoney gives his reasons for supposing There is, however, a line in the green, of approximate that the lighter the gas the less its quantity in our atmo-wave-length 5030, and another of about 5400. sphere, always assuming that no chemical compounds A few words may be said on the other companions of are known which would retain it on the earth, or modify argon. The last fractions of liquefied argon show the its relative amount. Therefore it appeared worthy of presence of three new gases. These are krypton, a gas inquiry whether it was possible to separate light and also first separated from atmospheric air, and characterised heavy gases from argon. by two very brilliant lines, one in the yellow and one in the green, besides fainter lines in the red and orange; metargon, a gas which shows a spectrum very closely resembling that of carbon monoxide, but characterised by its inertness, for it is not changed by sparking with oxygen in presence of caustic potash; and a still heavier gas, which we have not hitherto described, which we propose to name "xenon." Xenon is very easily separated, for it possesses a much higher boiling-point, and remains behind after the others have evaporated. This gas, which has been obtained practically free from krypton, argon, and metargon, possesses a spectrum The beautiful machine invented by Dr. Hampson has put it in our power to obtain, through his kindness and that of the "Brin" Oxygen Company, large quantities of liquid air. We were therefore able to avail ourselves of the plan of liquefaction, and subsequent fractional distillation, in order to separate the gases. On liquefying 18 litres of argon, and boiling off the first fraction, a gas was obtained of density 17 (0-16). This A Paper read before the British Assocation (Section B), Bristol Meeting, 1898. |