CONTENTS. 



ARTICLE V. 



Deieiiiimaiioa of the Longitude of several Stations near the Northern Boundary of 

 Ohio, from Transiis of the Moon, and Moon-culminating Stars, observed in 1835, 

 by Andrew Talcott, late Capt. U. S. Engineers. By Sears C. Walker. - - 241 



ARTICLE VI. 



On the Magnetic Dip at several places in the Stale of Ohio, and on the relative Hori- 

 zontal Magnetic Intensities of Cincinnati and I/ondon. By John Locke, M.D., 

 Professor of Chemistry and Pharm., Medical College of Ohio. In a Letter to John 

 Vaiiffhan, Esq., Librarian of the Am. Philos. Soc. .... 267 



ARTICLE VII. 

 Ne%v Formulfe Relative to Comets. By E. Nulty. ..... 275 



ARTICLE Vm. 



/Account of a Tornado, which, towards the end of August 1838, passed over the sub- 

 urbs of the City of Providence, in the State of Rhode Island, and afterwards over a 

 part of the Village of Somerset. Also an Extract of a Letter on the same Subject 

 from Zachariah Allen, Esq., of the City of Providence. Communicated by Robert 

 Hare, M.D.. Professor of Chemistry in the University of Pennsylvania. - - 297 



ARTICLE IX. 



Contributions to Electricity and Magnetism. By Joseph Henry, Professor of Natural 

 Philosophy in the College of New Jersey, Princeton. — No. III. — On Electro-Dy- 

 namic Induction. -----.--- 303 



ARTICLE X. 



Engraving and Description of an Apparatus for tlie Decomposition and Recomposition 

 of Water, employed in the Laboratory of the Medical Department of the University 

 of Pennsylvania. By R. Hare, M.D., Professor of Chemistry. - - - 339 



