UNITED STATES EXPLORING EXPEDITION. 



141 



U. S. SHIP VINCENNES. 

 VALPARAISO. 



OBSERVATORY, VALPARAISO. 



INSTRUMENTS USED ON SHORE. 



Standard barometer. 

 Thermometer attached. 



Thermometer, the bulb covered with black wool, hanging free one foot and a half from the ground, with 

 a north-and-south exposure. 



Thermometer, with bulb uncovered, in same situation. 

 Thermometer in shade in the open air. 



Thermometer in a hole six feet deep, and one foot in diameter. 

 Photometer. 



The temperature of water, and the thermometer at mast-head, were observed on board the Vincennes. 



36 



