CONTENTS OF VOL. XVI. 
NUMBER C.— JANUARY, 1840. Pagg 
On the 'rheory of Substitutions in Chemistry, proposed by M. 
Dumas. In a Letter to M. Pelouze from hi. Berzelius .... 1 
Mr. Jelfreys’s Experiments on Mechanical Exosmose with refer- 
ence to determining the Existence of any difference of Mag- 
nitude between liquid and gaseous Particles 10 
Mr. R. Potter on Photometry in connexion with Physical 
Optics 16 
Mr. Gulliver’s Observations on the Blood Corpuscles or Red 
Disks of the Mammiferous Animals. No. 1 23 
Mr. J. T. Cooper on the Employment of Carbon in Voltaic 
Combinations 35 
Prof. Sylvester on Derivation of Coexistence : Part I. Being 
the Theory of simultaneous simple homogeneous Equations 37 
Dr. Schafhaeutl on the Combinations of Carbon with Silicon 
and Iron and other Metals, forming the different species of 
Cast Iron, Steel, and Malleable Iron 44 
Mr. Halliwell’s Observations on the Authenticity of the Pass- 
age in the Treatise of Boetius de Geometrda on Numerical 
Contractions 51 
Mr. Warington on the coloured Films produced by Electro- 
chemical Agency and by Heat 52 
Rev. D. Williams on the Geology of Devon and Cornwall, 
with reference to a Paper read before the Geological Society 
on December 4, 1839 59 
New Books : — Miller’s Treatise on Crystallography, — Transac- 
tions of the Cambridge Philosophical Society, — Carpenter’s 
Principles of General and Comparative Physiology 65 
Proceedings of the Royal Astronomical Society 72 
Linnaean Society 76 
New System of Postage 78 
Letter Barometer 79 
New Scientific Books 79 
Meteorological Observations for November 1839 79 
Meteorological Observations made at the Apartments of the 
Royal Society by the Assistant Secretary, Mr. Roberton; 
by Mr. Thompson at the Garden of the Horticultural Society 
at Chiswick, near London; by Mr. VeaU at Boston; and by 
Mr. Dunbar at Applegarth Manse, Dumfries -shire 80 
NUMBER CL— FEBRUARY. 
Dr. Draper’s Account of some Experiments made in the South 
ofVirginia, on the Light of the Sun 81 
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