CONTENTS. V 



Page. 



X. Some account of Ithiel Town's improvement in the 

 construction and practical execution of Bridges, for 

 Roads, Railroads, and Aqueducts, . - - - 276 

 XL Description of an Economical Apparatus for Solidify- 

 ing Carbonic Acid, recently constructed at the Wes- 

 leyan University, Middletown, Conn.; by Prof. John 

 Johnston, .._.---- 297 

 XII. Observations made at Canton, China, on the Shooting 

 Stars of the 10th and lllh of August, 1839, in a letter 

 from Rev. Peter Parker, M. D. of Canton, to E. C. 

 Herrick, ..._---. 301 



XIII. Remarks chiefly on the Synonymy of several North 



American Plants of the Orchis Tribe; by Asa Gray, 



M. D., 306 



XIV. Account of the Capture and Death of a large Alligator, 313 

 XV. Synopsis of a Meteorological Journal, kept in the city 



of New York fur the years 1838 and 1839, including 

 also the mean results of the last seven years; by W. 

 C. Redfield, _.....- 323 



XVI. Notice of a Manual of Chemistry ; by Prof. John W. 



Webster, M. D., 329 



LVII. Engraving and Description of an Apparatus for the 

 Dscomposition and Recomposition of Water, employ- 

 ed in the Laboratory of the Medical Department of 

 the University of Penn. ; by Prof R. Hare, M, D., 336 



VIII. Improved Process for obtaining Potassium ; by Prof. 



Robert Hare, M. D., - - - - - - 338 



XIX. Engraving and Description of a Rotary Multiplier, or 

 one in which one or more Needles are made to revolve 

 by a Galvanic Current; by Prof R. Hare, M. D., - 339 



XX. Crania Americana ; or a comparative view of llie Skulls 

 of various Aboriginal Nations of North and South 

 America ; to which is prefixed an Essay on the Varie- 

 ties of the Human Species, illustrated by seventy eight 

 plates and a colored map ; by Prof. Samuel George 

 Morton, M. D., 341 



miscellanies. — DOMESTIC AND FOREIGN. 



1. Aurora Borealis of September 3, 1839, - . - . 375 



2. Meteoric Observations in November and December, 1839, 377 



