ASTRONOMICAL OBSERVATIONS 



Observations for Latitude of Van Rensselaer Harbor Observatory, and the Winter 

 Quarters of the Brig Advance. 



The first observation for latitude was made on September 12, 1853, with the 

 theodolite. Later observations were obtained by means of a sextant and artificial 

 horizon. The Gambey theodolite^ was furnished with repeating circles; the diame- 

 ter of the horizontal circle was six inches, with the limb divided from five to five 

 seconds, and provided Avith two verniers ; the vertical circle has four verniers, and 

 is of the same size and graduation as the horizontal circle. The following observa- 

 tions were made by Mr. Sonntag, at Washington, D. C, for the angular value of a 

 division of the large level belonging to the instrument. 



This instrument was much injured by a fall in the water, and rendered unfit for 

 use, by a second accident, two months later, in November, 1853, when it fell from 

 the pier at the observatory. It may be remarked, here, that Mr. Sonntag has 

 deduced approximate results from his observations with this instrument, and with 

 the sextant, insufficient refraction tables not permitting him to deduce final results. 



' This instrument, marked United States Coast Survey, No. 34, was kindly lent by the Superintend- 

 ent of the Survey, Prof. A. D. Bache. 



