Ordinary Form Research Articles

University and Educational Intelligence.

OXFORD.—On November 28 the preamble of a statute supplementing the ordinary form of procedure in Convocation by providing in certain circumstances for a special poll was moved by Prof. Geldart, supported by the Master of Balliol, and opposed on various grounds by Prof. Oman, Prof. Myres, and the president of Corpus. A division in a thin house showed twenty-five in favour of the preamble and twenty-four against it.

The Royal Society Conversazione

THE gentlemen's conversazione of the Royal Society was held in the society's rooms at Burlington House on Wednesday, May 10. The fellows and guests were received by Sir Archibald Geikie, K.C.B., president of the society, and many objects and experiments of scientific interest were exhibited. During the evening the Hon. R. J. Strutt gave a lecture on the afterglow of the electric discharge and on an active modification of nitrogen, and Mr. Joseph Bareroft lectured on adaptation to high altitudes in relation to mountain sickness. Experiments were shown by Prof. Strutt to prove that the well-known “afterglow” of Geissler tubes containing air is a phos phorescent flame, produced by the reaction of nitric oxide and ozone formed in the discharge. It was shown that nitrogen gives rise to a different kind of afterglow. The latter is regarded as resulting from the formation of an active modification of nitrogen, which slowly reverts to the ordinary form with luminosity. It was also shown that acetylene is spontaneously inflammable in this active nitrogen, and burns to cyanogen, the flame showing the characteristic spectrum of that gas.

A Shortened form of Synthetic Division and Some of its Applications

The ordinary form of synthetic division is probably familiar to most if not to all teachers of mathematics. I think the best arrangement for division by a binomial divisor is as follows:

An Improved Weight Dilatometer

THE ordinary form of weight dilatometer is troublesome to dry and fill, and the filling takes much time. Air bubbles are removed with difficulty, and after cooling to a low temperature there is a risk of loss of mercury while weighing the dilatometer unless special precautions are taken.

Electrical Recording Thermometers for Clinical Work

The President dealt with the application of resistance thermometers to the recording of clinical temperatures. Records of clinical temperatures have been obtained by Dr. Gamgee using a thermocouple in conjunction with sensitive recording instruments. The objections to thermocoupies are twofold. In the first place, the E.M.F.'s developed are so small that the recording instruments must be very sensitive and therefore unsuitable for ordinary use. In the second place, serious difficulties arise with regard to the thermostat which is necessary to maintain one of the junctions of the thermocouple at a constant temperature. The chief difficulty in connexion with the use of resistance thermometers for this kind of work lies in the heating effect of the current. In order to explain how this difficulty is overcome Prof. Callendar gave a short account of the conditions upon which the sensitiveness of a Wheatstone's bridge depends. He pointed out that in platinum thermometry, in order to obtain accurate compensation for the resistance of the leads, it is necessary that the ratio arms of the bridge should be equal, and he showed that this condition reduced the sensitiveness, which could be obtained by suitably varying the resistances by about 30 per cent. In joining up a bridge in work with resistance thermometers, Maxwell's rule for the positions of the battery and galvanometer which give maximum sensitiveness is seldom applicable. While Maxwell's arrangement actually gives the greatest sensitiveness, the heating effect of the current is so much greater that the trouble arising from this cause more than counterbalances the increased sensitiveness. The problem to be solved in designing a suitable thermometer for clinical work is, with a given galvanometer and resistance-box, to find the resistance of the thermometer which will give the most accurate results for a given heating effect of the current. This is given by the equation R=2G+S, where G is the resistance of the galvanometer and S that of one of the ratio arms. In the apparatus used at the meeting G=S=10 ohms giving R=30 ohms, a resistance for the thermometer which gives the convenient scale of 0.1 ohm increase per degree Centigrade. It is important in the construction of a thermometer for clinical work to secure quickness of action and to reduce the heating effect of the current. An ordinary tube-form of thermometer is good for laboratory work with sensitive galvanometers, but it is unsuitable for use with recorders. An ordinary form of thermometer takes about 1½ minutes to reach a steady temperature when taken from water at the temperature of the room and placed in water at 0° C., whereas a thermometer suitably designed will take up a steady temperature in about ten seconds. The pattern of the thermometer must also be suited to the purpose for which it is intended. Three types were shown, designed for mouth, rectal, and surface work. Experiments were performed proving that these thermometers fulfilled the necessary conditions. The recording instruments for use with these thermometers were briefly described. Prof. Callendar then showed continuous records obtained from a patient with a normal temperature. The temperature is generally very steady if the thermometer does not shift or the patient get wholly or partly out of bed. The effects of external changes of temperature were also shown, and simultaneous records taken on different parts of the body illustrated the fact that the temperature does not vary in the same way at all places. On the medical side there is a vast field for research which may eventually result in important additions to knowledge.

A Specific Gravity Balance for Large Rock Specimens

THE specific gravity balance represented in the accompanying illustration was devised by me some ten years ago for the determination of the specific gravity of hand specimens of rocks in the laboratory of the Geological Survey of India, Calcutta. In the ordinary form of Walker's balance the weight used on the short arm must be considerable in order to balance even a very small fragment of rock on the longer arm, and in consequence the specific gravity of an ordinary hand specimen has to be inferred from that of a small chip, which, unless the rock is of very homogeneous composition and texture, may give a very misleading result; and it is evident that if this form of balance were capable of accommodating a fairly large specimen, the whole instrument would have to be immoderately large. It occurred to me that if the specimen could be substituted for the heavy weight of Walker's balance, not only would it be possible to construct a balance of moderate size by which the determination of large specimens could be made directly, but the manipulation of the specimen and of the vessel containing the water might be greatly facilitated.

On a static method of comparing the densities of gases

The measurement of small differences of pressure to a fairly high degree of accuracy is not difficult. I have indicated a construction of a micromanometer which in its ordinary commercial form has a range of 3 or 4 cm. of height of a liquid column and reads to 0·005 mm. direct. Dr. Stanton describes a manometer constructed on Professor Chattock’s principle, having a reading sensitiveness of 0·0015 mm. of water, but the range is not stated. Lord Bayleigh, observing the contact between mercury surfaces and sharp points, obtained a sensitiveness of 0·0005 mm. of mercury with a range of about 1·5 mm. The idea of employing the micro-manometer for the determination of the relative densities of gases first occurred to me in 1901 in considering the corrections to a set of Pitot tube observations taken in a gas pipe situated some 20 feet above the manometer, and though a rough trial was carried out at the time it is only recently that I have had an opportunity of making an adequate test of the method.

A variety of thorianite from Galle, Ceylon

In a previous paper an account has been given of the composition and properties of a new mineral from Ceylon, chiefly composed of thorium dioxide (78 to 79 per cent.), to which the name thorianite was given. The mineral was shown to contain, besides thoria, a certain proportion of oxides of uranium varying in the three specimens analysed between 11 and 15 per cent., the uranium being present partly as dioxide and partly as trioxide, that is to say, in the same condition as in uraninite or pitchblende. It was shown that the evidence strongly supports the conclusion that thorianite and uraninite possess the same crystalline form and that they are isomorphous minerals. It is interesting to note that the new mineral naëgite, from Japan, which is essentially a silicate of uranium containing thorium, appears to be isomorphous with thorite (thorium silicate). It was suggested that the intimate association of thoria with oxides of uranium in thorianite is to he regarded as a case of isomorphous mixture. Such a mixture, or perhaps “solid solution,” might result from the crystallisation of thorianite from a fused mixture or magma containing the oxides of both elements. We have now obtained important confirmation of this view through the analyses of some unusually large crystalline fragments of thorianite received from the Galle District of Ceylon, which show that a still wider variation may occur in the proportions of the two oxides present in the mineral. This variety is composed of black lumps, usually of indefinite crystalline form, some of the pieces being apparently cubic. They are often partially covered with a brownish yellow substance containing a considerable amount of silica and probably derived from the associated rock. Some of the pieces weighed over 50 grammes, and were evidently portions of much larger masses. The fractured surfaces often showed a slightly less lustrous and more pitchy appearance than ordinary thorianite. The appearance of the mineral is thus intermediate between the small separate and cubical crystals of thorianite and the large masses without definite crystalline form, which are usually characteristic of uraninite. A small amount of material from Hinidumpattu in Galle consisted of small cubic crystal almost indistinguishable in appearance from ordinary thorianite. In hardness, optical properties, density and general physical characters this variety of thorianite closely resembles the ordinary form of the mineral.

A new device for separating minerals by means of heavy liquids

During the investigation of a zeolite it became necessary to separate small quantities of zeolitic material from a mixture of calcite and other heavier minerals; this could be done most easily by using a liquid of such density that the zeolite just floated, while all the other minerals sank to the bottom. A solution of potassium-mercuric iodide could not be used, as this reacts chemically with zeolites and alters their composition ; acetylene tetrabromide diluted with benzene was therefore chosen, and in consequence the apparatus had to be made entirely of glass. Certain dittlculties were found in using the ordinary form of glass separating apparatus, and to overcome these the form here described was devised.

A quartz‐thread vertical force magnetograph

The late Dr. Eschenhagen was the first to show that when the moment of inertia of the suspended system in a horizontal force magnetograph is made very much smaller than that employed in the ordinary form, it is possible to detect variations in the Earth's field of quick period. Since the study of these short‐period variations promises to be of considerable interest, the design of self‐recording instruments capable of giving satisfactory records becomes of importance. Both Dr. Eschenhagen2 and the author3 have described forms of apparatus suitable for recording the variations of the declination and horizontal component. The design of a satisfactory form of instrument to record the rapid variations of the vertical component presents, however, some very considerable difficulties.

A Quartz-Thread Vertical Force Magnetograph

The late Dr. Eschenhagen was the first to show that when the moment of inertia of the suspended system in a horizontal force magnetograph is made very much smaller than that employed in the ordinary form, it is possible to detect variations in the Earth's field of quick period. Since the study of these short-period variations promises to be of considerable interest, the design of self-recording instruments capable of giving satisfactory records becomes of importance. Both Dr. Eschenhagen2 and the author3 have described forms of apparatus suitable for recording the variations of the declination and horizontal component. The design of a satisfactory form of instrument to record the rapid variations of the vertical component presents, however, some very considerable difficulties.

A New Race of Musk-Ox

MR. ROWLAND WARD has on view at his establishment in Piccadilly a mounted adult male and female musk-ox from East Greenland, which differ from the ordinary form in having a large whitish patch on the face, as well as in certain other details of coloration. They may be made the types of a new race, under the name Ovibos moschatus wardi. The female was recently exhibited at the Zoological Society.

ELECTRIC RECORDING PERIMETER.

Of the many perimeters which have been devised for recording the field of vision, the instrument devised by Dr. Malcolm M. McHardy, of London, has met with the most favor. It is an excellent instrument, and whatever its defects, they are to be found in all similar forms of apparatus in which the test object is moved by a flexible cord. The instrument here shown was devised with a view of correcting the faults which experience shows exist in the ordinary form of perimeter. Apart from the use of small electric lamps for the fixation spot and for the test object, it differs in important details of construction from the usual form of perimeter. The arc which ordinarily carries the movable test object is replaced by a steel tube, at the end of which are cog-wheels for rotating a metal arm carrying a small electric lamp. Motion is transmitted to

Functional equation for the Selmer group of nearly ordinary Hida deformation of Hilbert modular forms

We establish a duality result proving the `functional equation' of the characteristic ideal of the Selmer group associated to a nearly ordinary Hilbert modular form over the cyclotomic $\mathbb{Z}_{p}$ extension of a totally real number field. Further, we use this result to establish a duality or algebraic `functional equation' for the `big' Selmer groups associated to the corresponding nearly ordinary Hida deformation. The multivariable cyclotomic Iwasawa main conjecture for nearly ordinary Hida family of Hilbert modular forms is not established yet and this can be thought of as an evidence to the validity of this Iwasawa main conjecture. We also prove a functional equation for the `big' Selmer group associated to an ordinary Hida family of elliptic modular forms over the $\mathbb{Z}_{p}^{2}$ extension of an imaginary quadratic field.

Phenomena Exhibited by Jackson Tubes

WHILE investigating the best methods of working the ordinary form of Jackson tubes during the last fourteen months, I have noted the following interesting phenomena.

The Magnetic Deflection of Cathode Rays

THE current number of the Electrician contains a translation of a very interesting paper by Herr P. Lenard, on the deflection of the cathode rays by a magnet. It is well known that when the cathode rays traverse a magnetic field they are deflected from their otherwise rectilineal path, and in the form of tube ordinarily employed this deflection increases with an increase in the pressure of the residual gas in the tube. In this particular the cathode rays behave just like a current of negatively charged particles projected from the cathode. The paths of such particles would be curved in a magnetic field, and the curvature would increase with a decrease in the speed with which the particles travel, i.e. they would be more curved in a denser and more resisting medium. The above explanation is not in accord with the results of the experiments the author has made, and which have led him to consider the cathode rays as phenomena in the ether. In fact, the author finds that when the observation tube and the tube in which the rays are generated, are separated by a gas-proof aluminium partition, so that the gaseous pressure can be varied in the two tubes independently, that the above explanation entirely fails, and that everything confirms his previous view that these rays are phenomena in the ether, and not electrically charged particles. For instance, if the pressure of the gas in the discharge-tube be kept constant, while that in the observing tube be lowered from 33 m.m. to 0˙021 m.m. it is found that the deflection produced remains constant. Higher pressures than 33 m.m. could not be employed, as under these circumstances the medium became so turbid to these rays as to entirely destroy all definition in the phosphorescent spot. If, however, the pressure of the gas in the observing tube be kept constant, while that in the discharge tube is varied, a marked influence on the position of the deflected spot is at once observable. Thus, if the pressure is altered so that the sparking distance in the discharge tube changes from 2 cm. to 4 cm. there is an alteration in the deflection of from 12˙2 m.m. to 8˙5 m.m. Thus it would appear that the difference in the deflection observed with varying gas pressures in the ordinary form of tube is not caused by difference of the medium in which the deflection is observed, but in the difference of the rays themselves, which are produced with varying pressures of gas. A curious deformation in the shape of the deflected phosphorescent spot was observed, for while the undeflected spot was always circular in form, the distribution of light being dependent on the turbidity (i.e. density) of the gas in the tube, in very turbid gases the edge of the spot is undefined. If the gas becomes rarer there appears in the centre of the spot a more or less sharply defined kernel, surrounded by a less bright penumbra. After deflection the spots become elliptical in shape, which may be due to the fact that the rays no longer met the screen at right angles, but when the gas was so rarefied that there was a central bright spot and a penumbra, the appearance of the spot was subject to sudden changes. While the position and shape of the central spot remained constant, the penumbra changed both in shape and position, sometimes even being quite separate from the bright spot. The penumbra was in every case more deflected than the bright spot, thus showing that the penumbra contains rays of greater deflectibility than the core, but never of less. This is borne out by previous experiments, which had shown that it is the rays that are most easily diffused that are most deflected.

VIII. On the measurement of the magnetic properties of iron

This paper contains some of the results and a description of the methods employed in a series of experiments on the rate of change of an electric current, immediately after the application or reversal of a constant electromotive force, in a circuit containing the magnetizing coil of a large electromagnet or the primary coil of a transformer. The experiments have been carried out in the Electrical Laboratories of the Lose Polytechnic Institute, Terre Haute, Ind. The results seem to be of considerable interest, and the method of studying the magnetic properties of iron here proposed has, I believe, some important advantages in many practical cases where the magnetic circuit is closed and of large section. In the experimental determination of the magnetic properties of iron it has been usual to determine by means of a series of successive experiments the value of the total magnetization pft)duced by different magnetizing forces. From these results the magnetic permeability of the iron, the self-induction of the circuit, and so forth, can, of course be calculated. Several methods are well known, by means of which reliable results can be obtained in this way, but they are, in many cases, inconvenient. For closed magnetic circuits, for example, the method commonly employed has been to measure, by means of the current induced in a coil of wire surrounding the iron, and in circuit with a ballistic galvanometer, the changes of magnetization produced by different changes of the current in a magnetizing coil. By this method, the value of the integral ∫ n 2 n 1 L de , or its equivalent ∫ l2 l1 e dt can bre measured. In the first form of the integral, c 1 and c 2 are the initial and final values of the current in, and L the coefficient of induction of, the magnetizing coil. In the second form, t 2 — t 1 is the interval of time required for the current to change from the value c 1 to the value c 2 , and e is the back electromotive force induced by the rate of change of the current at any instant between the times t 1 and t 2 . When the masses of iron experimented on are large, the interval of time t 3 — t 2 becomes too great for the value of the integral to be accurately measured by means of any ordinary form of ballistic galvanometer joined in circuit with a second, or induction, coil surrounding the iron.

The Reflector with the Projection Microscope

THE lantern is now used for so many purposes—scientific, photographic, and recreative—that any improvement in its construction will be acceptable. When we look into this instrument whilst at work we must be disappointed at the large quantity of light lost by reflection and by dispersion—light which ought to go to the illumination of the screen. In the ordinary form of the lantern three lenses of dense glass are employed as condensers. Each of these six surfaces reflects and scatters the light, and the glass itself is absorbent of its rays.

THE FIRST LARVAL OR POST–EMBRYONIC STAGE OF THE PEA AND BEAN WEEVILS

In No. 9–10, Vol. IV., of “Insect Life,” an account was given of the post-embyronic larva of the Bean Weevil, attention being called to some most interesting characteristics of this larva, which is possessed of temporary thoracic legs and some other strctures which admirably serve its locamotive needs until it has entered the bean, when, with a cast of the skin, they are lost and larva assumes the ordinary apodous form of weevil larvæ.

Scientific Serials

THE American Journal of Science, October 1891. Some of the possibilities of economic botany, by George Lincoln Goodale. This is the Presidential address delivered before the American Association for the Advancement of Science, at Washington in August last.—On the vitality of some annual plants, by T. Holm. The author enumerates several species of plants which show a tendency to vary from annual to biennial or perennial.—A method for the separation of antimony from arsenic by the simultaneous action of hydrochloric and hydriodic acids, by F. A. Gooch and E. W. Danner.—Notes on allotropic silver, by M. Carey Lea. The blue form of allotropic silver is mainly considered. The action of light on this form is remarkable, for its effect is first to increase the sensitiveness to reagents and then to completely destroy it. This reversing action is analogous to that which light exerts upon silver bromide. Mr. Lea has also examined the point as to whether in the reduction of silver, the allotropic or the normal form is produced, and he finds that when the silver passes from the condition of the normal salt or oxide to that of the metal, the reduced silver always appears in the ordinary form. But when the change is first to sub-oxide or to a corresponding sub-salt, the silver presents itself in one of its allotropic states.—structural geology of Steep Rock Lake, Ontario, by Henry Lloyd Smyth.—On the so-called amber of Cedar Lake, North Saskatchewan, Canada, by B. J. Harrington. The resin or “retinite” examined by the author had a hardness of about 2˙5, and a specific gravity I ˙055 at 20° C. An analysis gave for its composition, carbon 80˙03, hydrogen 10˙47, and oxygen 9˙5O.—Geological horizons as determined by vertebrate fossils, by O. C. Marsh. The method of defining geological horizons by vertebrate fossils was first used by the author in 1877, and appears to afford the most reliable evidence of climatic and other geological changes. It is now extended and revised. A section accompanies the paper representing, in their geological order, the successive strata at present known with certainty from characteristic vertebrate fossils.