110 
ME. A. E. OXLEY ON THE INFLUENCE OF MOLECULAE 
complexity with change of temperature, may modify the temperature coefficient of 
the magnetic property of a substance. The large change of molecular constitution 
during the transition from the liquid to the crystalline state should therefore be 
accompanied by a sudden change of the magnetic property. 
The relation between molecular complexity and specific diamagnetic susceptibility 
Xd may be written,* on the above hypothesis, in the form 
Xd = g . AM p .(l) 
where AM p is the total diamagnetic moment produced in a complex of type p by the 
application of an external magnetic field H. n p is the number of complexes of the 
type p per gramme. During a transition from one degree of complexity to another, 
several types of complexes may coexist. The summation is extended over all such 
types. 
The corresponding expression for the specific paramagnetic susceptibility xp is 
Xp = 2 . ( 2 ) 
where c p is the Curie constant per particle of type p. Since, in the above equations, 
n p is a function of the temperature, characteristic for each substance, it is probable 
that the irregularities of the temperature susceptibility curves obtained by Prof. 
Honda,! Prof, du Bois,| and Mr. Owen§ are due to the presence of this variable 
factor. 
The application of (l) and (2) to the case of aqueous solutions of salts of the ferro¬ 
magnetic elements, for which n p is approximately a linear function of the temperature, 
gives indirect evidence of the existence of molecular complexes in solution|| (see also 
footnote, p. 134 infra). 
It is intended in the present research to test more fully the hypothesis stated 
above, which is involved in (l) and (2), by investigating the magnetic susceptibility 
of a number of substances over a wide range of temperature. To simplify the 
problem, the substances chosen are all diamagnetic and consist chiefly of organic 
compounds. The small electrical conductivity of the latter allows us to neglect any 
effect which may arise from the presence of moving intermolecular charges.IF The 
diamagnetic property will therefore be a concern of the internal structure of the 
* Loc. cit., p. 489. 
t ‘Ann. der Phys.,’ IV., 32, p. 1027, 1910. 
| ‘Versl. Kon. Ak. v. Wetensch.,’ Amsterdam, XII., p. 596, 1910. 
§ ‘Versl. Kon. Ak. v. Wetensch.,’ Amsterdam, XIV., p. 637, 1912. 
|| ‘Proc. Camb. Phil. Soc.,’ vol. XVII., p. 65. 
H Sir J. J. Thomson, ‘Eapports du Congres Int. Paris,’ 1900, vol. III., p. 148; also Schrodinger, ‘Sitz. 
d. k. Akad. Wien,’ CXXI., p. 1305, 1912. [See, however, the article by H. A. Lorentz, ‘ Mathematische 
Vorlesungen an der Universitat Gottingen,’ VI., p. 189, 1914.— Note added March , 1911/..'] 
