CONTENTS. 



Art. I. On the Diluvial Theory, and on the Origin of the 

 Valleys of Auvergne. By Charles Daubeny, 

 M. d! F. R. S. Professor of Chemistry in the Uni- 

 versity of Oxford, &c. &c. In a Letter to Profes- 

 sor Jameson, « - - - 201 

 II. On the Characters and Affinities of certain Genera, 

 chiefly belonging to the Flora Peruviana. By Mr 

 David Don, Librarian to the Linnean Society, 

 Member of the Imperial Academy Naturae Curioso- 

 rum, of the Royal Botanical Society of Ratisbon, 

 and of the Wernerian Society of Edinburgh, &c. 

 (Concluded from p, 122.) - - 229 



III. On the adaptation of the Fly-wheel and Pulley of 



the Turning-lathe to a given Length of Band. By 

 Mr Edward Sang, Teacher of Mathematics, Edin- 

 burgh, ----- 239 



IV. On the Development of the Vascular System in the 



Foetus of Vertebrated Animals. Part II. By Al- 

 len Thomson, M. D. late President of the Royal 

 Medical Society. Communicated by the Author. 

 (Concluded from p. 111.) — 

 Development of the Respiratory Organs in the Ophidia, 



Chelonia and Sauria, - - - - 251 



Development of the Respiratory Organs in Birds, 255 



Development of the Respiratory Organs in the Foetus 

 of Mammalia, ..... 262 



V. Analysis of a powerful Chalybeate Water from Vi- 

 car's Bridge, near Dollar in Clackmannanshire. By 

 Arthur Connell, Esq. F. R. S. E. Communi- 

 cated by the Author, - - • S84 



