LONDON, EDINBURGH, AND DUBLIN

PHILOSOPHICAL MAGAZINE

AND

JOURNAL OF SCIENCE.

CONDUCTED BY

SIR ROBERT KANE, LL.D. F.R.S. M.R.I.A. F.C.S.
SIR WILLIAM THOMSON, KNT. LL.D. F.R.S. &c.

AND

WILLIAM FRANCIS, PH.D. F.L.S. F.R.A.S. F.C.S.

"Nec aranearum sane textus ideo melior quia ex se fila gignunt, nec noster
vilior quia ex alienis libamus ut apes." JUST. LIPS. Polit. lib. i. cap. 1. Not.

VOL. XLVII.-FOURTH SERIES.
JANUARY-JUNE 1874.

LONDON.

TAYLOR AND FRANCIS, RED LION COURT, FLEET STREET,
Printers and Publishers to the University of London;

SOLD BY LONGMANS, GREEN, Reader, and DYER; KENT AND CO.; SIMPKIN, MARSHALL.
AND CO.; AND WHITTAKER AND CO.;—AND BY ADAM AND CHARLES 'BLACK,
AND THOMAS CLARK, EDINBURGH; SMITH AND SON, GLASGOW:-
HODGES, FOSTER, AND CO, DUBLIN:-PUTNAM, NEW
YORK:-AND ASHER AND CO., BERLIN.

"Meditationis est perscrutari occulta; contemplationis est adinirari perspicua . . . . . Admiratio generat quæstionem, quæstio investigationem, investigatio inventionem."-Hugo de S. Victore.

CONTENTS OF VOL. XLVII.

(FOURTH SERIES.)

NUMBER CCCIX.-JANUARY 1874.

Page

Mr. J. Y. Buchanan on an Apparatus for Gas-analysis. (With a Plate.)..

1

6

M. H. Herwig on the Disintegration of the Electrodes in the
Galvanic Arc of Light

Prof. Challis's Theory of the Source of Terrestrial Magnetism. 14
Mr. R. S. Brough on Wheatstone's Bridge....

Prof. Challis's further Discussion of the Analytical Principles

of Hydrodynamics, in Reply to Mr. Moon..

M. A. F. Sundell on the Electromotive and Thermoelectric
Forces of some Metallic Alloys in contact with Copper....
Mr. S. Roberts on a simple Condensing Collector for Fric-
tional Electrical Machines

Prof. W. F. Barrett on the Molecular Changes that accom-
pany the Magnetization of Iron, Nickel, and Cobalt

Notices respecting New Books:

Mr. J. M. Wilson's Elementary Geometry...

Proceedings of the Royal Society:

25

28

51

56

Dr. J. H. Gladstone and Mr. A. Tribe on an Air-Battery. 61
Mr. O. Reynolds on the Condensation of a Mixture of
Air and Steam upon Cold Surfaces ..

Proceedings of the Geological Society:

Mr. S. Sharp on the Oolites of Northamptonshire.—
Part II.

67

74

On some Phenomena of Illumination, by A. Lallemand
On a Process for verifying the Nodes in a Sounding Pipe, by
M. Bourbouze

77

80

NUMBER CCCX.-FEBRUARY.

Lord Rayleigh on the Manufacture and Theory of Diffractiongratings.....

Mr. O. Heaviside on Wheatstone's Bridge

Mr. J. Croll on the Physical Cause of Ocean-currents
Prof. W. H. Miller on Quartz, Ice, and Karstenite

81

93

94

122

Prof. E. C. Pickering's Measurements of the Polarization of the Light reflected by the Sky ard by one or more Plates of

Glass

127

Page

Mr. R. Moon's Remarks on the Analytical Principles of Hydrodynamics, in Reply to Professor Challis

143

Dr. Helmholtz on Galvanic Polarization in Liquids free from
Gas

145

Notices respecting New Books:

Mr. W. T. Pierce's Treatise on Practical Solid or Descrip-
tive Geometry: embracing Orthographic Projection and
Perspective or Radial Projection...

153

Prof. M. Yarnall's Catalogue of Stars observed at the
United States Naval Observatory during the years 1845
to 1871 ...

155

155

On a new Determination of the Mechanical Equivalent of Heat,
by H. Serrano y Fatigati ....
On the Expansibility of Ebonite by Heat, by F. Kohlrausch.. 156
On the Discharge of Electrified Conductors, by J. Moutier.. 157

NUMBER CCCXI.-MARCH.

The Earl of Rosse on the Electric Resistance of Selenium .. 161
Mr. J. A. Phillips on the Composition of certain Mine Waters. 164
Mr. J. Croll on the Physical Cause of Ocean-currents. (With
a Plate.)......

168

190

M. H. Herwig on the Number and Weight of the Molecules
of Ether contained in Electric Conductors
Lord Rayleigh on the Manufacture and Theory of Diffraction-
gratings.

193

M. J. L. Soret on some Phenomena of Polarization by Diffusion of Light...

205

M. A. Terquem on the Transformation of the Vibroscope into a Tonometer, and its employment for the Determination of the Absolute Number of Vibrations

212

Notices respecting New Books:

The Rev. S. Hawtrey's Introduction to the Elements of
Euclid

215

Proceedings of the Royal Society:

Lieut. Sale on the Action of Light on the Electrical Re-
sistance of Selenium

216

Mr. F. Chambers on the Diurnal Variations of the Wind
and Barometric Pressure at Bombay

Mr. D. M'Kichan's Determination of the Number of
Electrostatic Units in the Electromagnetic Unit .... 218
Messrs. Stewart and Tait on the Heating of a Disk by
rapid Rotation in vacuo.....

219

228

Proceedings of the Geological Society:

Dr. J. Bryce on the Jurassic Rocks of Skye and Raasay. 229
Mr. D. Mackintosh on the more remarkable Boulders of
the North-west of England and the Welsh Borders.. 230