CONTENTS OF VOL. XXVIII 



(FOURTH SERIES.) 



NUMBER CLXXXVI.— JULY 1864. 



Page 



Prof. J. C. Poggendorff on the Extra Current of the Induction- 

 Current 1 



Mr. C. Packe on the Discrepance between the English and 

 French Barometer Scales ; and on the Corrections necessary 



in reducing the Readings to the Freezing-point 8 



Mr. T. K. Abbott on the Probability of Testimony and Argu- 

 ments 12 



Prof. Tyndall's Notes on Scientific History 25 



M. P. Tchebychef on a Modification of Watt's Parallelogram. . 51 

 Mr. P. E. Chase on the Barometer as an Indicator of the Earth's 



Rotation and the Sun's Distance 55 



Notices respecting New Books : — Dr. Apjohn's Manual of the 



Metalloids 59 



Proceedings of the Royal Society : — 



Mr. G. G. Stokes on the supposed Identity of Biliverdine 

 with Chlorophyll, with remarks on the Constitution of 



Chlorophyll 63 



Drs. Pliicker and Hittorf on the Spectra of Ignited Gases 



and Vapours 64 



Mr. B. Stewart on Sun Spots 68 



Mr. J. P. Gassiot on a Train of Eleven Sulphide-of-carbon 



Prisms arranged for Spectrum Analysis 69 



Proceedings of the Geological Society : — 



Mr. J. W. Salter on some New Fossils from the Lingula- 



flags of Wales 72 



Messrs. Hull and Green on the Mills tone -grit of North 

 Staffordshire, and the adjoining parts of Derbyshire, 



Cheshire, and Lancashire 72 



Mr. W. P. Blake on the Geology and Mines of the Nevada 



Territory 72 



Mr. H. Seeley on the Red Rock in the Section at Hun- 

 stanton 73 



The Rev. D. Honeyman on the Geology of Arisaig, Nova 



Scotia 74 



Mr. J. W. Kirkby on some Remains of Fishes from the 



"Upper Limestone" of the Permian Series of Durham. 74 

 Mr. P. M. Duncan on the Fossil Corals of the West Indian 

 Islands 74 



