Viii CONTENTS. 



Abtiou. Pao* 



XIL— An Experimental Enquiry into the Relative Povers of 

 the Locomotive Engine, and the Resistance of Railway 

 Gradients. By Wm. Faiebaihn, F.R.S., V.P 149 



XIII. — On the Security and Limit of Strength of Tubular 

 Girder Bridges constructed of Wrought Iron. By 

 William Faiebaibn, F.R.S., V.P 179 



XIV. — On the Cause of Unequal Falls of Rain in Cumberland. 



By Alderman Thomas Hopkins 196 



XV.— On Impossible and certain other Surd Equations. By 



RoBEBT Haelet 207 



XVI. — On Impossible Equations. By Peofessor Finlat 236 



XVII. — On the Composition of the Gas produced by the Joint 

 Distillation of Tar and Water at a high temperature. 

 By John Leigh, M.R.C.S.,F.C.S.,&c 243 



XVIII. — On the Chemical Changes attending the Formation of 

 Coal, and on the relation of these Changes to the 

 Philosophy of Gas-making. By John Leigh, 

 M.B,C.S., F.C.S 250 



XIX. — On Linear Constructions. By Rev. Thomas Pentngton 



KiBKjviAN, A.M., Rector of Croft- with-Southvrorth 279 



XX. — On the Analysis of Gaseous Mixtures. By John Leigh, 



M.R.C.S., F.C.S 297 



XXI. — A Description of some supposed Meteorites found in 



SeamsorCoal. ByE.W.BiNsaT 306 



XXII. — On the Volvox Globator. By William Cbaweobd 

 Williamson, Professor of Natural History, Owens 

 College 321 



XXIII. — On the Structure and Affinities of the Plants hitherto 

 known as Sternbergiaj. By W^. C. Wilijamson, Pro- 

 fessor of Natural History, Owens College 340 



