CONTENTS OF VOL. XXI. 
(FOURTH SERIES.) 
NUMBER CXXXVII.—JANUARY 1861. 
Page 
Mr. T. A. Hirst on Ripples, and their relation to the Velocities 
pemmeeats. (With a Plate.) .. 2.44 saekoa wes Gives 
Sir David Brewster on certain Affections of the Retina...... 20 
M..W. Siemens’s Proposal for a new reproducible Standard 
Measure of Resistance to Galvanic Currents (With a Plate.) 25 
Mr. G. B. Jerrard’s Remarks on Mr. Harley’s paper on Quintics. 39 
Mr. J. 5. Stuart Glennie on the Principles of the Science of _ 
Motion (Mechanics, Physics, Chemics............se+005 41 
_ Mr. W. Crookes on the Opacity of the Yellow Soda- ‘Flame to 
Pee enewh Colour 664. Sor eda he  sereoaal. 55 
Mr. T. ‘Tate’s Experimental Researches on the Laws of Absorp- 
tion of Liquids by Porous Substances ...........++-00. ee 
Prof. Challis on a Theory of Magnetic Force .............. 65 
Mr. C. W. Siemens on a new Resistance Thermometer...... 73 
Proceedings of the Royal Society :— 
Mr. F. Jenkin on the Insulating Properties of Gutta Percha. 75 
On the Lithium Spectrum, by William Crookes, Esq. ...... 79 
On a constant Copper-carbon Battery, by Julius Thomsen.... 80 
NUMBER CXXXVIII.—FEBRUARY. 
Prof. J. D. Forbes’s Note respecting Ampére’s Experiment on 
the Repulsion of a Rectilinear Electrical Current on itself. 
(With a Plate.) .. : 81 
F, W. and A. Dupré o: on the existence of a Fourth Member of 
merc Carerum Group of Metals... yis6 oid Gece ee tails: - 86 
Prof. Schcenbein on the Insulation of Antozone ............ 88 
Mr. J, Cockle’s Note on the Remarks of Mr. Jerrard........ 90 
Prof, Challis on a Theory of Magnetic Force .............- 92 
Dr. Matthiessen on an Alloy which eS used as a Standard 
of Electrical Resistance. . 107 
Mr. T. Tate’s Experimental Researches on the Laws of Absorp- 
tion of Liquids by Porous Substances’...............-5 - 115 
Dr. Atkinson’s Chemical Notices from Foreign Journals .... 120 
Prof. Sylvester’s Note on the Numbers of Bernoulli and Euler, 
and a new Theorem concerning Prime Numbers.......... 127 
Mr. W. Dittmar on a new Method of arranging Numerical 
ebles (With 4 Plate ndirees iia cteipela thduay diascat «- 137 
_ Mr. W. Dittmar on Graphical Interpolation ............-- 139 
