(2) If the magnetic lines of force are at right angles to che longitudinal direction of the wire projecting into the field, the tractive force at right angles to the lines of force is smaller in iron than the force p#. The ratio p#/P1 (where p# and pl are the tractive forces parallel and at right angles to the lines of force respectively), which with mean strengths (about H=100) is greater than 100, rapidly decreases as the field increases and appears to approach unity-Wiedemann's Annalen, No. 1, 1895.

.

ON THE INFLUENCE OF MAGNETIZATION ON THE CONSTANTS OF

ELASTICITY IN IRON. BY A. BOCK. The result of this research is stated as follows by the author :By magnetization the constants of elasticity of soft iron, the modulus of torsion, and the modulus of elasticity are certainly not altered by more than 3 per cent. The series of observations indicate that the flexure diminishes, at the same time the torsion seems also to diminish, while the ratio of the lateral contraction to the longitudinal expansion increases. Iron is more incom. pressible in the magnetic field. Nothing can be alleged with certainty as to magnetized steel bars. These results are in perfect agreement with the well-known investigations of G. Wiedemann, and they may be deduced from the theory propounded by that author on the assumption of rotating molecular inagnets.-Wiedemann's Annalen, No. 3, 1895.

K

ON THE MAGNETIZATION OF IRON BY VERY SMALL FORCES.

BY WERNER SCHMIDT. The experimental results of this research are given by the author in the following statements :

1. Steel follows small magnetizing forces more rapidly than iron.

2. The magnetization function « of mild steel is greater for small forces than that of iron. In the present case « (steel) is to k (iron) as 4 is to 3. The stronger magnetization ordinarily observed in iron is only met with in greater magnetizing forces, for instance, H>1.

3. The constancy of the magnetizing function « for very small forces, first observed by Lord Rayleigh, is confirmed. The boundary of proportionality between magnetizing forces and magnetic moments may be taken with sufficient accuracy for technical purposes as near the magnetizing force H,=0.06. This value represents a rather sudden transition in the curve k=f(H). Below this the deviations from proportionality are only very feeble, that is the curve k=f(H) passes into a parallel to the H-axis. The point at which it can be identified with a straight line (parallel) is different according to the nature of the iron investigated, and especially according to the sensitiveness of the apparatus used for the measurements, without varying much from a certain mean value which may be regarded as lying between the magnetizing forces H,=0.03 and 0·0+.- Wiedemaun's Annalen, No. 4, 1895.

INDEX to VOL. XXXIX.

225;

some, 447.

crust, 93.

ACOUSTICAL experiments, on

Analytischen Chemie,

Crookes's Select Methods in Che-
Allen (H. N.) on energy movements mical Analysis (chiefly Inorganic),

in the medium separating electri- 305 ; Kennedy's A Few Chapters

fied or gravitating particles, 357. in Astronomy, 307; Geikie's The
Alternating currents, on some ex- Great Ice Age and its Relation
periments with, 377.

to the Antiquity of Man, 379.
Ampère, on a neglected experiment Brill (J.) on densities in the earth's

of, 534.
Analyser, on a simple form of har- Bryan (G. H.) on a simple graphic
monic, 367.

illustration of the determinantal
Aniline, on the influence of tem- relation of dynamics, 531.

perature on the specific heat of, Burke (J.) on the luminescence of
47, 143.

glass due to kathode rays, 115.
Aschkinass (E.) on the refraction Burton (Dr. C. V.) on some acousti-

and dispersion of electrical rays, cal experiments, 447.
144.

Calorimetry, on the use of aniline as
Atomic attractions, analysis of mole- a standard in, 47, 143.
cular into, 44.

Carbonic acid, on an experiment
heat in the periodic series of the with solid, 308.
elements, on the role of, 106. Clark cell when producing a current,
Ayrton (Prof. W. E.) on a simple on the, 295, 375.

apparatus for determining the Combination of substances in the
mechanical equivalent of heat, liquid and solid condition, on the

160; on tests of glow-lamps, 389. heat of, 510.
Baron (Rev. R.), geological notes of tones, on the objective reality
a journey in Madagascar, 542.

of, 341, 452
Bismuth, on the influence of mag- Condenser, on a modification of the

netic fields on the electrical con- ballistic-galvanometer method of
ductivity of, 143.

determining the electromagnetic
Blake (Rev. J. F.) on some points in capacity of a, 172.

the geology of the Harlech area, Cooke (J. H.) on the Pleistocene
141.

beds of the Maltese islands, 542.
Blanshard (C. T.) on the role of Copper compounds, on the flame-

atomic heat in the periodic series spectra of, 124.
of the elements, 106.

Crystals, on the rotational coefficients
Bock (A.) on the influence of mag- of thermal conductivity in, 476.

netization on the constants of Cubes, on Ronayne's, 183.
elasticity in iron, 548.

Currents, on some experiments with
Bonney (Prof. T. G.) on the geology alternating, 229, 377.

of the Narborough district, 543. Deeley (R.M.) on glacier-grains, 453.
Books, new :-Kohlrausch's Intro- Dewar (Prof. J.) on the liquefaction

duction to Physical Measurements, of gases, 298.
137; Watts's Dictionary of Che- Dielectric, on the passage of an oscil-
mistry, 138; Ostwald's Die Wis- lator wave-train through a plate
senschaftlichen Grundlagen der of conducting, 309.
Phil. Mag. S. 5. Vol. 39. No. 241. June 1895. 2 P

Dielectric power of ice, on the, 144. Green (Prof. A. H.) on some recent
Dissipation function, on the kinetic sections in the Malvern Hills, 140.
interpretation of the, 455.

Gresley (W. S.) on the Midland
Draper (D.) on the marble beds of coalfield, 547; on the iron ores of
Natal, 545.

the Lake Superior Region, 547.
Dynamics, on a simple graphic illus- Griffiths (A.) on some experiments
tration of the determinantal rela- with alternating currents, 229.
tion of, 531.

Griffiths (E. H.) on the influence of
Earth's crust, on densities in the,

temperature on the specific heat of
93.

aniline, 47, 143.
Edser (E.) on the objective reality Harmonic analyser, on a simple form
of combination tones, 341.

of, 367.
Electrical notes, 175.

Haycraft (H. C.) on a simple appa-
rays, on the refraction and dis-

6

Larmor (J.) on the significance of Olszewski (Prof. C.) on the liquefac-

Wiener's localization of the pho- tion of gases, 188.
tographic action of stationary Oscillatur wave-train, on the passage
light-waves, 97.

of an, through a plate of conduct-
Lee (J. B.) on a new instrument for ing dielectric, 309.
surveying by means of photo- Oxygen, on the liquefaction of, 192 ;

,
graphy, 544

absorption spectrum and colour of
Leighton (T.) on the Lower Green- liquefied, 197.
sand of East Surrey, 546.

Paraffin, on the specific inductive
Light-waves, on the photographic capacity of, under slowly and
action of stationary, 97.

rapidly changing fields, 78.
Liquefaction of gases, on the, 188, Periodic series of the elements, on
298.

the rôle of atomic heat in the, 106.
Lumière (A. & L.) on silvering glass Permeability, on the value of the
in the cold, 387.

magnetic, for rapid electrical os-
Luminescence produced on breaking cillations, 297.
vacuum-bulbs, on the 115.

Perot (A.) on the dielectric power
Luminosity of gases, on the, 122. of ice, 144.
Macfarlane (Prof. A.) on Col. Hime's Photographic action of stationary

Outlines of Quaternions,' 135. light-waves, on the, 97.
Magnetic field, on the change of Photography, on a new instrument

length in soft iron wire placed in for surveying by means of, 544.
a uniform, 226.

Pickering (S. U.) on the heat of
permeability, on the value of combination of substances in the
the,

for rapid electrical oscillations, liquid and solid condition, 510.
297.

Pitch, on the subjective lowering of,
Magnetism, on mirrors of, 213.

447.
Magnetization, on the relation be- Porter (A. W.) on the influence of

tween electromagnetic stress and, the dimensions of a body on its
254; on the influence of, on the thermal emission, 268.
constants of elasticity in iron, Preston (Dr. S. T.): comparative
548; of iron by very small forces, review of some dynamical theories
on the, 548.

of gravitation, 145.
Marr (J. E.) on the tarns of Lake- Prytz (Prof. K.) on an experiment
land, 544.

with solid carbonic acid, 308.
Martini (T.) on the velocity of sound Quaternions, on the equation i=j=
in gases, 142.

k=N-1=-i=-;= -k in, 135.
Mechanical equivalent of heat, on a Radiation of heated gases, on the,

simple apparatus for determining 460.
the, 160.

Resistance, on the measurement of,
Medley (E. A.) on tests of glow- 175.
lamps, 389.

Richarz (F.) on Helmholtz's electro-
Mirrors of magnetism, on, 213. chemical theory, 529.
Molecular force, on the laws of, 1. Ronayne's cubes, on, 183.
Natanson (Prof. L.) on the kinetic Rosing (B.) on the change of length

interpretation of the dissipation in soft iron wire placed in a uni-
function, 455; the kinetic form magnetic field, 226.
energy of the motion of heat and Rücker (Prof. A. W.) on the objec-
the corresponding dissipation func- tive reality of combination tones,
tion, 501.

on

a ne-

Schnyder von Wartensee prize Thompson (Prof. S. P.) on mirrors
question for 1897, 388.

of magnetism, 213; on
Schuster (Prof. A.) on the measure- glected experiment of Ampère,

ment of resistance, 175; on the 534.
scale-value of the late Dr. Joule's Threlfall (Prof. R.) on the Clark cell
thermometers, 477.

when producing a current, 295.
Silvering glass in the cold, on, 387. Tin chromic-chloride cell, on the,
Skinner (S.) on the Clark cell when 444.

producing a current, 375; on the Vries (Dr. G. de) on the change of

tin-chromic chloride cell, 444. form of long waves advancing in
Smithells (Prof. A.) on the lumi- a rectangular canal, and on a new
nosity of gases, 122.

type of long stationary waves, 422.
Solids, kinetic theory of, 16. Walker (M.) on mirrors of mag-
Soret (C.) on the rotational coeffi- netism, 213.

cients of thermal conductivity in Waves, on the change of form of
crystals, 476.

long, advancing in a rectangular
Sound, on the velocity of, in gases, canal, and on a new type of long
142.

stationary, 422.
Specific inductive capacity of a sub- Wave-train, on the passage of an

stance under slowly and rapidly oscillator, through a plate of con-
changing fields, on a method for ducting dielectric, 309.
comparing the values of the, 78; Weber (M.) on electromagnetic trac-
of water, alcohol, &c., 134.

tive force, 547.
Sutherland (W.) on the laws of Womack (F.) on a modification of
molecular force, 1.

the ballistic-galvanometer method
Thermal conductivity and emissivity, of determining the electromagnetic
on the determination of, 280.

capacity of a condenser, 172.
emission, on the influence of Yule (G. U.) on the passage of an
the dimensions of a body on its, oscillator wave-train through a
268.

plate of conducting dielectric, 309;
Thermometers, on the scale-value of on a simple form of harmonic
the late Dr. Joule's, 477.

analyser, 367.

END OF THE THIRTY-NINTH VOLUME.

Printed by TAYLOR and Francis, Red Lion Court, Fleet Street.