ly CONTENTS OF VOL. XXI.—FOURTH SERIES. 
Page 
Proceedings of the Royal Society :— 
Prof. Maxwell on the Theory of Compound Colours, and 
the Relations of the Colours of the Spectrum........ 141 
Prof. Faraday on, Regelatioi: oeuica.<004+ ssc oo eee os, 146 
Proceedings of the Geological Society :— 
Mr. D. Forbes on the ‘Geology of Bolivia and Southern Peru. 154 
Prof. Huxley on a New Species of Macrauchenia ...... 156 
Mr. J. W. Salter on the Paleozoic Fossils brought by 
Mr..D. Forbes from Bolivian, . 2: ..s%se-«cl = 5 eee a+ > oe 
On the Polarization of Light by Diffusion, by G. Govi...... 157 
On Electric Endosmose, by M..C. Matteucci vi: /7 ). eae 159 
NUMBER CXXXIX.—MARCH. 
Prof. Maxwell on Physical Lines of Force .............++« 161 
Mr. A.H. Church on the Benzole Series, . sia c'oe I ¥ Rare 
Mr. A. Cayley’s Note on the Theory of Determinants........ 180 
Prot. Kirchhoff on the Chemical Analy sis of the Solar Atmo- 
sphetez, &. tp. aw ol adblon nacins ot, Dale ee 185 
Mr. I’. A. Hirst on Ripples, and their relation to the Velocities 
of Currents. (With a Plate.) .. 188 
M. G. R. Dahlander on the Equilibrium of a Fluid Mass ‘revol- 
ving freely within a Hollow Spheroid about an Axis which is 
not its Axis of symmetry ... .198 
Dr. Woods's Remarks on Sainte-Claire Deville’s Theory ‘of Dis- 
BOCIALION WG QI 5 Mallets. Wel Hace ie be deuolle etn setae a 202 
Prof. Swan on the ian: Correction of ee Baro- 
meters | ..i5 206 
Mian A.. Cayley’ s Note on Mr. Jerrard’s Researches on 1 the Equa- 
tion of the. Fifth ‘Order .°..4.4 Edy dvd cpa i ee 210 
Prof. Davy on some further applications of the Ferrocyanide of 
Potassium in Chemical Analysis ........00.eeeeeeeee «. 214 
Proceedings of the Royal Society :-— 
MM. Matthiessen and Holzmann on the Effect of the 
Presence of Metals and Metalloids upon the Electric Con- 
duetivity:of Pure Copper... #42'7. 2 SPP 7. ae 224 
Dr. Chowne on the relations between the Elastic Force of 
Aqueous Vapour, at ordinary Temperatures, and its 
Motive Force in producing Currents of Air in Vertical 
Tubes. re DEFT RY Be 
M. Kopp « on the relation. between Boiling point and Com- 
position in Organic Compounds ........ 0.0.2 eee 227 
Messrs. W. Fairbairn and ‘IT’. Tate on the Density of Steam 
at all Teniperabares * 00.5. 2 ee Pee ee .. 230 
Proceedings of the Geological Society :— 
Prof. Nicol on the Structure of the North-west Highlands. 233 
Mr. T. F. Jamieson on the Geclogical Structure of the 
South-west Highlands of Scotland ..............-. 235 
The Rey. H. Mitchell on the position of the Beds of the 
