1V CONTENTS OF VOL. XIX.—FOURTH SERIES. 
Page 
On the Pseudo-diascope, by F. O. Ward........ 2.00. 0e-- 79 
On the occurrence of Urea in the Organs of the Plagiosto- 
mous Mishes, by G. Stadeler. 7... 2.60. ees vine ea nie ae 
NUMBER CXXV.—FEBRUARY. 
Prof. Helmholtz on Vowel Sounds ...... wile a eke oe eal 
Prof. Challis on a Theory of Molecular Forces .... 88 
Prof. Cavalleri on a New Seismometer constructed in 1 the ‘Col- 
leve at Morza, \(Watn 8 Plate) sesesise Oars so siden ale © 102 
Dr. Atkinson’ s Chemical Notices from Foreign Journals .... 116 
Prof. Knoblauch on the Interference of Heat . A: eed) 15: 
Dr. Wright on the Behaviour of Mercury as an ‘Electrode Ares Ibe) 
Prof. LeConte on the Correlation of Physical, Chemical, and 
Vital Force, and the Conservation of Force in Vital Phe- 
MIOMENA, \iape2) 2)-2 Sal. Apel AWS, Aas ARs mile 
Notices respecting New Books : — 
Mr. S. H. Winter’s Elementary Geometrical Drawing .. 148 
Proceedings of the Royal Society :— 
Sir J. F. W. Herschel on Colour-Blindness............ 148 
Proceedings of the Geological Society :— 
Prof. Owen on some Remains of Polyptychodonfrom Dorking. 158 
Mr. 8. Allport on some Fossils from near Bahia, South 
AIRCTICH le hts & egos ee ae ee ERE se 158 
Dr. Dawson on some Fossils from the Coal- ra ye eS lag 
Nova Scotia .... 159 
The Rev. P. B. Brodie on ‘the Occurrence of F ootsteps ‘of 
Chirotherium in the Upper Keuper of Warwickshire .. 160 
Prof. Goeppert on the Flora of the Silurian, Devonian, 
and Lower Carboniferous Formations ..... 160 
Captain Spratt on the Freshwater Deposits of Bessarabia, 
Moldavia, Wallachia, and Bulgaria ..... 160 
Messrs. T. R. Jones and W. K. Parker on the Recent and 
Fossil Foraminifera of the Mediterranean Area ...... 161 
Optical Lecture Experiments, by Prof. Knoblauch ........ -- 162 
On the Fixation of the Magnetic Image, by M. J. Nickles .. 164 
NUMBER CXXVI.—MARCH. 
Mr. M. Ponton on certain Laws of Chromatic Dispersion .... 165 
Prof. Davy on a Simple and Expeditious Method of estimating 
Phosphoric Acid and its Compounds, which is particularly 
applicable to the aera of os aad Manures and the 
Ashes of Plants . ay asl Bute’ Suni baie <p. ave (6 000505 hil 
