Page images
PDF
EPUB

(2) If the magnetic lines of force are at right angles to the 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/p (where p and pare 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 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 incompressible 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 magnets.-Wiedemann's Annalen, No. 3, 1895.

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:

K

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 (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 <=ƒ(H1). 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 0.04.- Wiedemann's Annalen, No. 4, 1895.

INDEX TO VOL. XXXIX.

[blocks in formation]

Atomic attractions, analysis of mole-
cular into, 44.

heat in the periodic series of the
elements, on the rôle of, 106.
Ayrton (Prof. W. E.) on a simple
apparatus for determining the
mechanical equivalent of heat,
160; on tests of glow-lamps, 389.
Baron (Rev. R.), geological notes of
a journey in Madagascar, 542.
Bismuth, on the influence of mag-

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

Blake (Rev. J. F.) on some points in
the geology of the Harlech area,

141.

Blanshard (C. T.) on the rôle of
atomic heat in the periodic series
of the elements, 106.
Bock (A.) on the influence of mag-
netization on the constants of
elasticity in iron, 548.

Bonney (Prof. T. G.) on the geology
of the Narborough district, 543.
Books, new:-Kohlrausch's Intro-
duction to Physical Measurements,
137; Watts's Dictionary of Che-
mistry, 138; Ostwald's Die Wis-
senschaftlichen Grundlagen der
Phil. Mag. S. 5. Vol. 39. No.

Analytischen Chemie, 225;
Crookes's Select Methods in Che-
mical Analysis (chiefly Inorganic),
305; Kennedy's A Few Chapters
in Astronomy, 307; Geikie's The
Great Ice Age and its Relation
to the Antiquity of Man, 379.
Brill (J.) on densities in the earth's
crust, 93.

Bryan (G. H.) on a simple graphic
illustration of the determinantal
relation of dynamics, 531.

Burke (J.) on the luminescence of
glass due to kathode rays, 115.
Burton (Dr. C. V.) on some acousti-
cal experiments, 447.

Calorimetry, on the use of aniline as
a standard in, 47, 143.
Carbonic acid, on an experiment
with solid, 308.

Clark cell when producing a current,
on the, 295, 375.

Combination of substances in the
liquid and solid condition, on the
heat of, 510.

tones, on the objective reality
of, 341, 452.

Condenser, on a modification of the
ballistic-galvanometer method of
determining the electromagnetic
capacity of a, 172.

Cooke (J. H.) on the Pleistocene
beds of the Maltese islands, 542.
Copper compounds, on the flame-
spectra of, 124.

Crystals, on the rotational coefficients
of thermal conductivity in, 476.
Cubes, on Ronayne's, 183.
Currents, on some experiments with
alternating, 229, 377.

Deeley (R.M.) on glacier-grains, 453.
Dewar (Prof. J.) on the liquefaction
of gases, 298.

Dielectric, on the passage of an oscil-
lator wave-train through a plate
of conducting, 309.
241. June 1895. 2 P

Dielectric power of ice, on the, 144.
Dissipation function, on the kinetic
interpretation of the, 455.
Draper (D.) on the marble beds of
Natal, 545.

Dynamics, on a simple graphic illus-
tration of the determinantal rela-
tion of, 531.

Earth's crust, on densities in the,
93.

Edser (E.) on the objective reality
of combination tones, 341.
Electrical notes, 175.

rays, on the refraction and dis-
persion of, 144.
Electrochemical theory, on Helm-
holtz's, 529.

Electromagnetic capacity of a con-
denser, on a modification of the
ballistic-galvanometer method of
determining the, 172.

stress, on, 254.

tractive force, on, 547.
Elements, on the rôle of atomic heat
in the periodic series of the, 106.
Energy movements in the medium
separating electrified or gravitating
particles, on, 357.

Eumorfopoulos (N.) on the determi-
nation of thermal conductivity and
emissivity, 280.

Evershed (J.) on the radiation of
heated gases, 460.
Flame-spectra of salts of copper and
gold, 122.

Garbasso (E.) on the refraction and
dispersion of electrical rays, 144.
Gases, on the luminosity of, 122;
on the velocity of sound in, 142;
on the liquefaction of, 188, 298;
experiments on the radiation of
heated, 460.

Geological Society, proceedings of
the, 140, 542.
Glacier-grains, on, 453.

Glass, on the specific inductive

сара-
city of, under slowly and rapidly
changing fields, 78; on the lumi-
nescence of, 115; on silvering, in
the cold, 387.

Glow-discharge, on the, 387.
Glow-lamps, on tests of, 389.
Gold, on the flame-spectrum of the
trichloride of, 130.

Gravitation, comparative review of
some dynamical theories of, 145.

Green (Prof. A. H.) on some recent
sections in the Malvern Hills, 140.
Gresley (W. S.) on the Midland
coalfield, 547; on the iron ores of
the Lake Superior Region, 547.
Griffiths (A.) on some experiments
with alternating currents, 229.
Griffiths (E. H.) on the influence of
temperature on the specific heat of
aniline, 47, 143.

Harmonic analyser, on a simple form
of, 367.

Haycraft (H. C.) on a simple appa-
ratus for determining the mecha-
nical equivalent of heat, 160.
Heat, on a simple apparatus for de-
termining the mechanical equiva-
lent of, 160; on the kinetic energy
of the motion of, 501.

of combination of substances
in the liquid and solid condition,
on the, 510.
Helmholtz's electrochemical theory,
on, 529.

Henderson (J. B.) on the influence
of magnetic fields on the electrical
conductivity of bismuth, 143.
Hennessy (Prof. H.) on Ronayne's
cubes, 183.

Herz (A.) on the glow-discharge,

[blocks in formation]

Iron, on the influence of magnetiza-
tion on the constants of elasticity
in, 548; on the magnetization of,
by very small forces, 548.

wire, on the change of length
in soft, placed in a uniform mag-
netic field, 226.

Jones (E. T.) on electromagnetic
stress, 254.

Joule's thermometers, on the scale-
value of, 477.

Korteweg (Prof. D. J.) on the change
of form of long waves advancing
in a rectangular canal, and on a
new type of long stationary waves,

422.

Lake (P.) on the Denbighshire series
of South Denbighshire, 141.

Larmor (J.) on the significance of
Wiener's localization of the pho-
tographic action of stationary
light-waves, 97.

Lee (J. B.) on a new instrument for
surveying by means of photo-
graphy, 544.

Leighton (T.) on the Lower Green-
sand of East Surrey, 546.
Light-waves, on the photographic
action of stationary, 97.
Liquefaction of gases, on the, 188,
298.

Lumière (A. & L.) on silvering glass
in the cold, 387.
Luminescence produced on breaking
vacuum-bulbs, on the 115.
Luminosity of gases, on the, 122.
Macfarlane (Prof. A.) on Col. Hime's
'Outlines of Quaternions,' 135.
Magnetic field, on the change of
length in soft iron wire placed in
a uniform, 226.

permeability, on the value of
the, for rapid electrical oscillations,
297.

Magnetism, on mirrors of, 213.
Magnetization, on the relation be-
tween electromagnetic stress and,
254; on the influence of, on the
constants of elasticity in iron,
548; of iron by very small forces,
on the, 548.

Marr (J. E.) on the tarns of Lake-
land, 544.

Martini (T.) on the velocity of sound
in gases, 142.

Mechanical equivalent of heat, on a
simple apparatus for determining
the, 160.

Medley (E. A.) on tests of glow-
lamps, 389.

Mirrors of magnetism, on, 213.
Molecular force, on the laws of, 1.
Natanson (Prof. L.) on the kinetic
interpretation of the dissipation
function, 455; on the kinetic
energy of the motion of heat and
the corresponding dissipation func-
tion, 501.

Newton (R. B.) on a collection of

fossils from Madagascar, 543.
Northrup (E. F.) on a method for
comparing the values of the specific
inductive capacity of a substance
under slowly and rapidly changing
fields, 78.

Olszewski (Prof. C.) on the liquefac-
tion of gases, 188.

Oscillator wave-train, on the passage
of an, through a plate of conduct-
ing dielectric, 309.

Oxygen, on the liquefaction of, 192;
absorption spectrum and colour of
liquefied, 197.

Paraffin, on the specific inductive
capacity of, under slowly and
rapidly changing fields, 78.
Periodic series of the elements, on
the rôle of atomic heat in the, 106.
Permeability, on the value of the
magnetic, for rapid electrical os-
cillations, 297.

Perot (A.) on the dielectric power
of ice, 144.

Photographic action of stationary
light-waves, on the, 97.
Photography, on a new instrument
for surveying by means of, 544.
Pickering (S. U.) on the heat of
combination of substances in the
liquid and solid condition, 510.
Pitch, on the subjective lowering of,

447.
Porter (A. W.) on the influence of
the dimensions of a body on its
thermal emission, 268.
Preston (Dr. S. T.): comparative
review of some dynamical theories
of gravitation, 145.

Prytz (Prof. K.) on an experiment
with solid carbonic acid, 308.
Quaternions, on the equation i=j=
k=√1=-i-j= -k in, 135.
Radiation of heated gases, on the,
460.

Resistance, on the measurement of,
175.

Richarz (F.) on Helmholtz's electro-
chemical theory, 529.
Ronayne's cubes, on, 183.
Rosing (B.) on the change of length
in soft iron wire placed in a uni-
form magnetic field, 226.
Rücker (Prof. A. W.) on the objec-
tive reality of combination tones,
341.

Sadowsky (A.) on some experiments

with alternating currents, 377.
St. John (C. E.) on the value of the
magnetic permeability for rapid
electrical oscillations, 297.
Schmidt (W.) on the magnetization
of iron by very small forces, 548.

Schnyder von Wartensee prize-
question for 1897, 388.
Schuster (Prof. A.) on the measure-
ment of resistance, 175; on the
scale-value of the late Dr. Joule's
thermometers, 477.

Silvering glass in the cold, on, 387.
Skinner (S.) on the Clark cell when
producing a current, 375; on the
tin-chromic chloride cell, 444.
Smithells (Prof. A.) on the lumi-
nosity of gases, 122.
Solids, kinetic theory of, 16.
Soret (C.) on the rotational coeffi-
cients of thermal conductivity in
crystals, 476.

Sound, on the velocity of, in gases,

142.

Specific inductive capacity of a sub-
stance under slowly and rapidly
changing fields, on a method for
comparing the values of the, 78;
of water, alcohol, &c., 134.
Sutherland (W.) on the laws of
molecular force, 1.
Thermal conductivity and emissivity,
on the determination of, 280.

emission, on the influence of
the dimensions of a body on its,
268.
Thermometers, on the scale-value of
the late Dr. Joule's, 477.

Thompson (Prof. S. P.) on mirrors
of magnetism, 213; on a ne-
glected experiment of Ampère,
534.
Threlfall (Prof. R.) on the Clark cell
when producing a current, 295.
Tin chromic-chloride cell, on the,
444.

Vries (Dr. G. de) on the change of
form of long waves advancing in
a rectangular canal, and on a new
type of long stationary waves, 422.
Walker (M.) on mirrors of mag-
netism, 213.

Waves, on the change of form of
long, advancing in a rectangular
canal, and on a new type of long
stationary, 422.
Wave-train, on the passage of an
oscillator, through a plate of con-
ducting dielectric, 309.

Weber (M.) on electromagnetic trac-
tive force, 547.

Womack (F.) on a modification of
the ballistic-galvanometer method
of determining the electromagnetic
capacity of a condenser, 172.
Yule (G. U.) on the passage of an
oscillator wave-train through a
plate of conducting dielectric, 309;
on a simple form of harmonic
analyser, 367.

END OF THE THIRTY-NINTH VOLUME.

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

« PreviousContinue »