TABLE OF CONTENTS 



NUMBER VII.— JANUARY. 



Page 

 Prof. M. A. Kupffer's Note on the Mean Temperature of 



Irkoutsk, in Siberia 1 



Prof. F. Rudberg's Observations on the Magnetic Intensity at 



Paris, Brussels, Gottingen, Berlin, and Stockholm 4? 



Mr. R. Potter on a New and Simple Heliostat 6 



Rev. P. Keith on the Structure of Living Fabrics {continued) 8 

 Rev. J. Challis's Remarks on Lagrange's Proof of the Principle 



of Virtual Velocities 16 



Prof. G. B. Airy on the Phenomena of Newton's Rings, when 

 formed between two transparent Substances of different re- 

 fractive Powers 20 



Mr. B. Bevan on certain Defects in the British Almanac 30 



Mr. W. Sturgeon on the Theory of Magnetic Electricity (con- 

 tinued) 32 



Dr. W. H. Fitton's Notes on the History of English Geology ... 37 



Prof. J. F. Daniell on a New Oxy-hydrogen Jet 57 



Mr. R. Murphy on the Existence of a Real or Imaginary Root 



to any Equation 60 



Mr. J. D. Forbes's Notice respecting the Determination of the 

 Geographical Position of the Village of Chamouni, and the 



Convent of the Grand St. Bernard 61 



Mr. G. Fairholme's Description of a Species of Natural Micro- 

 meter, with Observations on the Minuteness of Animalcula ; 



— in a Letter to Sir David Brewster 64* 



Proceedings of the Linnaean Society 67 



Zoological Society 68 



Action of Sulphurous Acid on the Persalts of Iron — Improve- 

 ment in the Quality of Iron and Steel, from their becoming 



Rusty when buried in the Earth 75 



Caoutchouc — Formation of iEther by Fluoride of Boron — Per- 

 oxide of Barium 77 



Analysis of Paraffine — Red Oxide of Phosphorus 78 



Hydrate of Phosphorus 79 



Meteorological Observations made by Mr. Thompson at the 

 Garden of the Horticultural Society at Chiswick, near 

 London ; by Mr. Giddy at Penzance, and Mr.Veall at Boston 80 



NUMBER VIII.— FEBRUARY. 



Mr. R. Potter on the Modification of the Interference of two 

 Pencils of Homogeneous Light produced by causing them 

 to pass through a Prism of Glass, and on the Importance of 

 the Phenomena which then take place in determining the 

 Velocity with which Light traverses refracting Substances. . 81 



