n CONTENTS. 



PAGE 



Art. VII. On the Dynamic Equivalent of Current Electricity, 

 and on a fixed Scale for Electromotive Force in 

 Galvanometry. By Mr William Petrie. Com- 

 municated by the Author, ... 64 



VIII. On the Application of Electricity and Heat, as 

 Moving Powers. By Mr William Petrie. Com- 

 municated by the Author, . . . 66 



IX. On the Intensity of Sound in the Barified Air over 

 High Mountains. By Ch. Martins, D.M. & S. 

 Communicated by the Author, ... 70 



X. Analysis of the Waters of the Mediterranean. By 



M. Uziglio, 79 



XI. On the Minerals of the Auriferous Districts of 



Wicklow. By William Mallet, Esq., . 82 



XII. On the Natural History of the Naked- Eyed Medusae 



or Jelly Fishes, . . . . . 85 



XIII. On the Ante-Columbian Discovery of America. By 



Dr Elton. Communicated by Dr Traill, 90 



XIV. Remarks on the Snow-Line in the Himalaya. By 



Captain Thomas Hutton, . . . 93 



XV. On a Remarkable Compound of Iodine and Codeine, 

 By Thomas Anderson, M.D., F.R.S.E., Lec- 

 turer on Chemistry, Edinburgh. Communicated 

 by the Author, 103 



XVI. M. Barrande on the Silurian System of Bohemia. 

 Communicated by James Nicol, F.R.S.E., Pro- 

 fessor of Geology, Queen's College, Cork, . 107 



XVII. On the Optical Properties of a Compound of Iodine 

 and Codeine. By William Haidinger, Esq., 

 Councillor of Mines in Austria, and Professor of 

 Mineralogy, F.R.S.E., Member of the Wernerian 

 Nat. Hist. Soc. of the Royal Academies of Berlin, 

 Munich, &c., &c. Communicated by the Author, 122 



