Philosophical Magazine Series 6 ISSN: 1941-5982 (Print) 1941-5990 (Online) Journal homepage: http://www.tandfonline.com/loi/tphm17 XXIX. On the magnetic susceptibilities of hydrogen and some other gases Také Soné To cite this article: Také Soné (1920) XXIX. On the magnetic susceptibilities of hydrogen and some other gases , Philosophical Magazine Series 6, 39:231, 305-350, DOI: 10.1080/14786440308636042 To link to this article: http://dx.doi.org/10.1080/14786440308636042 Published online: 08 Apr 2009. Submit your article to this journal Article views: 6 View related articles Citing articles: 16 View citing articles Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=6phm20 Download by: [RMIT University Library] Date: 20 June 2016, At: 12:34 E 3o5 XXIX. On the MAgnetic Susceptibilities of llydrogen uud some otl~er Gases. /33/TAK~; S0~; *. INDEX TO SECTIONS. 1. INTRODUCTION. ~O. METI~OD OF 5LEASUREMENT. o. APPARATUS :FOR }IEASU14EIMF~NT. (a) Magnetic bMance. (b) Compressor and measuring tube. 4. PIt0CEDUI{E :FOR BIEASUREMENTS. (a) Adjustment of the measuring tube. (b) Determination of the mass. (c) Method of filling the measuring tube with gas. (d) Electromagnet. (e} Method of experiments. 5. Ain. 6. OXYGEN. ~. CARBON DIOXIDE. 8. NITROGEN. 9. ItYDI~0G~N. (a) Preparation of pure hydrogen gas. (b) Fillin~ the measuring tube with the gas. (e) YCesults el'magnetic measurement. (d} Purity of the hydrogen gas. 10. CONCLUDING REMARKS. wi. INTRODUCTION. N the electron theory of magnetism, it is assumed that I the magnetism is duo to electrons revolving about the positive nucleus in the atom; and hence the electronic structure of the atom has a very important bearing on its magnetic properties. The models of the atoms or molecules hitherto proposed are so constructed as to explain only the phenomena of light; but the question whether the nature of atomic or molecular magnetism, due to the system of the ,'evolving electrons, agrees with the results of observation or not, is in most cases not touched at all. For example, Downloaded by [RMIT University Library] at 12:34 20 June 2016 BoAr's model t of hydrogen molecules explains very satis- factorily the light dispersion of hydrogen ; but its magnetic polarity is para,nagnetic in contradiction to the observed fact that hydrogen gas is diamagnetic. A correct theory of the constitution of the atoms or molecules must, however, ,lot only explain the phenomena of light, but also their magnetism. In this respect, a knowledge of the ,nagne~ic susceptibility of various gases, especially those of hydrogen * Communicated by the Author. t N. Bobr, Phil. Mag. xxvi. p. 857 (1913); P. Debye, 8itz. d. math.- phys. Klas. d. Akad. d. Wissensch. Miinchen, p. 1 (1915). _Phil. Mag. S. 6. Vol. 39. No. 231. ~larch 1920. X 306 511". Tak6 Sond o~ the ~llag~etic Susceptibilities and t~elium, is very import~mt. In spite of this fact, owing to the great difficult)- in measuring the susceptibility of gases, only a few cases--oxygen and air--are known, in wldch the value of susceptibility can be given wi'th fair accuracy. For other gases the values of susceptibility by different observers show large discrepancies not only in magnitude, but sometimes in si~n. Hence an exact and more extended determination or' the magnetic susceptibility of different gases was thought to be desirable. The present investigation was undertaken at the suggestion of Protbssor K. Honda about two years ago and is still in progress. On the other ha,d, the theory of magnetiz'~tion of' the gases has been successfully developed by P. Langevin * ; the conclusions arrived at agree in many points with the observed facts ; but there are many others which cannot be explained by his theory. Aecordi,g to him, the molecules of a paramagnetic gas have each a definite magnetic moment, which is comparable with that of a ferromagnetic substance, but those of a diamagnetic gas h.ave no magnetic moments, so that there is a fundamental distinction between para- magnetic and diamagnetic substances. The diamagnetism is of an atomic nature and theretore cannot vary with temperature, or by the change of states, or by any mode of chemical combination. These conclusions do not, however, accord with the fact that the susceptibility-atomic weight curve for elementst cha,ges quite continuously in passing from .the parama'gnetic elements to the diamagnetic, and tliat the suscef!tibility of tin :~ changes its sign at the trans- formatidn point and duri,g melting. Professor K. Hondaw mQdified Langevin's theory or' p~ramagnetic and diamagnetic gases so as to include tho magnetization of liquid and solid states, and gave a different aspect to the distinction beiween paramagnetieand die,magnetic substances. According to him the obser~ed~- susceptibility X is the sum of' the Langevin Downloaded by [RMIT University Library] at 12:34 20 June 2016 paramagnetic and diamagnetic susceptibilities ~p and Xd ; that is which may be paramagnetic or diamagnetic, according as Xv ~ X~l" Since Xp depends on the configuration of the atoms in a P. Langevin, Ann. de chim. et dephys, viii. p. 70 (1905). t K. Honda, Ann. d. PAys. xxxii, p. 1027 (1910). ~: K. IIondal/oc. c/t. w K. Honda, Sci. ICep. iii. p. 171 (1914). of Hydrogen and some other Gases. 307 molecule, it may change with temperature, or by the change of states, etc. ; and hence the observed susceptibility X may change in a similar way, as actually observed. The con- tinuous change of the susceptibility-atomic weight curve from the paramagnotic elements to diamagnetic above referred to is also explained oil the same basis. According to the above ~heory, the molecules of a para- magnetic substance must thereibre possess a definite magnetic moment, while those of a diamagnetic substance have only a small magnetic moment or none. In Bohr's model of a hydrogen molecule, ~p is decidedly greater than X~*, and therefore :Z or Xp+X~ is positive in contradiction to th~ observed fact. In a recent paper, Professors Honda and Okubo t proposed a new theory of magnetization of the gases. According to the kinetic theory of gases, besides translational motions, the molecules of a gas are continuously making rotational motions about their centres of mass; and in their theory, these molecules are treated as gyroscopes. Since the axis oi~ rotation of the molecules does not in general coincide with the magnetic axis, the magnetic moment of the molecules is supposed to be resolved in the direction of the axis of rotation and that perpendicular to it. Under the action of a magnetic field, the paramagnetic polarization results from the former component and the diamag~,etic polarization from the latter, and therefore a resultant polarization is the sum of these two. The resultant may be positive or negative, according as paramagnetic polarization <> diamagnetic polarization. The theory proves that the sign of the magnetization of a gas depends on the shape of tim molecules, and not in the least on their magnetic moment. In fact, a gas whose molecules have a definite magnetic moment comparable with Downloaded by [RMIT University Library] at 12:34 20 June 2016 those of iron may be diamagnetic, provided the axis of rotation is perpendicular to the magnetic axis. This kind of diamagnetism is not dealt with in any of the previous theories. In order to test these theories it is necessary to have the correct values of susceptibility of different gases, which al'e at present scarcely known. One of the chief diffi.ulties which we encounter in the determination of' the magnetic susceptibility of gases, lies in the preparation of pure gases, i. e. those which are perfectly J. Kunz, Phys. Rev. xii p. 59 (1918). + K. Honda and J. 0kubo, Sci. Rep. vii. p. 141. (1918) ; Phys. Rev. viii. p. 6 (1919). X2 308 Mr. Takd Son4 on the ~]fagnetic Susceptibilities free from air, and the other in the extreme smallness of the volume susceptibility of gases. In the present research I paid special attention to tile preparation of pure gases, the removal of the air contained in the generators and purifiers being the constant object of my endeavour. As for the measurement of the magnetic susceptibility, I succeeded in overcoming the difficulty by constructing an apparatus, by means of which I could seal gases in a glass tube at a very high pressure without the least fear of leakage. This apparatus enabled me to use in each ease a quantity of gas sufficient for the determination of its magnetic susceptibility and density. A special magnetic balance of high sensibility was constructed for measuring the magnetic force acting on the gas which was sealed in the glass tube and placed in a strong magnetic field. The details of the method and the arrangement of the experiments are given in the following pages. w 2. METHOD OF MEASUREMENT. The method of measurement is based on the following principle :~A cylindrical rod made of the material to be tested is vertically suspended between the horizontal pole- pieces of an electromagnet from an arm of a magnetic balance specially constructed, the lower end of the rod being placed in Fig. 1. the axial line of the pole-pieces and 7--- /'x the upper end in a place where the J magnetic field is negligibly small. [~ Suppose at first the balance to I i be in equilibrium, with no mag- "\ ti .~ netic field acting on it, by applying "~ the field the rod is supposed to U undergo a slight upward displace- //) % ment ~a, but in equilibrium acted Downloaded by [RMIT University Library] at 12:34 20 June 2016 on by a force f arising from an inclination of the balance beam.