CONTENTS. 



Table I. Position of the Principal Observatories. From the American Nauti- 

 cal Almanac. .......... 4 



" II. To convert Parts of the Equator in Arc into Sidereal Time, or to con- 

 vert Terrestrial Longitude in Arc into Time. From Downes, 

 U. S. Almanac for 1845, as given in Lee's Tables and Formulcs^ 

 2d edition, p. 146 et seq. ........ 6- 



" III. To convert Sidereal Time into Parts of the Equator in Arc, or to 

 convert Time into Terrestrial Longitude in Arc. From Downes, 

 U. S. Almanac for 1845, p. 150, and Lee's Tables and Formulce. 8 



" IV. For converting Sidereal Time into Mean Solar Time, and Mean 



Solar Time into Sidereal Time. From Lee's Tables and Formulce. 9 



" V. Correction of the Time obtained by Observation of the Sun, in order 

 to have the True Time of the Clock. Communicated by Prof. 

 B. Peirce, of Harvard University 10 



" VI. For computing Terrestrial Surfaces, by Delcros. From the Annuaire 



Meteor ologique de la France for 1850, p. 73 et seq. . . .12 



