XU CONTENTS. 



ARTICLE XVIII. 



Observations upon the Meteors of August. By C. G. Forshey, City Engineer of Natchez, 



and late Professor of Mathematics and Civil Engineering, Jefferson College, Mississippi. 265 



ARTICLE XIX. 



On the Change effected in the Nitrates of Potash and Soda by the limited Application of 

 Heat, with the View of obtaining pure Oxygen, by which they are only partially con- 

 vertible into Hypo-nitrites: also on a Liquid and a gaseous ethereal Compound, resulting 

 from the reaction of nascent hypo-nitrous Acid with the Elements of Alcohol. By Ro- 

 bert Hare, M. D., Professor of Chemistry in the University of Pennsylvania. - - 277 



ARTICLE XX. 



Descriptions of new Species and Genera of Plants in the natural Order of the Composite, 

 collected in a Tour across the Continent to the Pacific, a Residence in Oregon, and a 

 Visit to the Sandwich Islands and Upper California, during the years 1834 and 1835, 

 By Thomas Nuttall. --------- 283 



ARTICLE XXI. 



Descriptioit of Nineteen new Species of Colimacea. By Isaac Lea. ... 455 



Donations to the Library and Cabinet. -..--.. 457 



t • 



