vi CONTENTS. 
Page 
Arr. VIII.—Experiments on the Expansive Force of Steam. By 
Professor GusTAV MAGNUS .... 0.62005. 0dve vest en eens 218 
Art. IX.—On the Force requisite for the production of Vapours. 
By Professor Gustav MAGNUS .........- +2 e0es ee eeee 235 
Arr. X.—On the Allotropy of Elementary Bodies as one of the 
causes of the Isomerism of their Compounds. By J. J. Ber- 
GERMS | etch os <x vialwials waneiiate Clan 5.0 0m b> eee 240 
Art. XI.—On the Morphology, Classification and Distribution of 
the Trilobites. By Dr. Emmericn of Meiningen ........ 253 
Arr. XII.—On the Employment of Polarized Light in studying 
various questions of Chemical Mechanics. By M. Biot .. 292 
PART XV. 
Arr. XII.—On the Employment of Polarized Light in studying 
various questions of Chemical Mechanics. By M. Bior 
(continued ).. 2s. 2s ystex eyeelgnn «a abe ihe oe 345 
Art. XIII.—Photometrical Method of estimating the Intensity 
of ordinary and extraordinary Rays, as also those of reflected 
light ; with Remarks on M. Cauchy’s increase in the Inten- 
sity of Light by total reflexion, and reproduction of Fresnel’s 
formula for total reflexion, &e. By F. E. Neumann .... 402 
Art. XIV.—On the Nature of Agua Regia, on Hyponitrie Acid 
as an oxidizing agent, on the Constitution of that Acid, and 
the part which it acts towards Organic Substances. By Dr. 
Kane, Professor of Chemistry in Brussels 
Art. XV.—On the Incandescence and Fusion of Metallic Wires 
by Electricity.’ By Perer Riess’... 0c esac. soe eee 432 
Art. XVI.—On the Periodical Variations in the Pressure of the 
Atmosphere in the Interior of Continents. By Professor 
ERS Wi DOVE: ovis os sites lee ioe'o ute ntetetanene ere ie ener ee 476 
Art. XVII.—On the Polarization of Light by Reflexion, especially 
by doubly refracting bodies. By A. SzeEBECK 
