CHAPTER IV. 



PROGRESS OF ASTRONOMY IN THE UNITED STATES. 



SECTION I. 



ASTRONOMICAL OBSERYATORIES IN THE UNITED STATES. 



IT is but a few years since practical astronomy began 

 to be cultivated in -the United States in an efficient and 

 systematic manner. Until recently, the instruments in 

 our possession were but . few and small, and the observa- 

 tions which were made, seldom extended beyond the no- 

 tice of the time of a solar or lunar eclipse, or the meas- 

 urement of a comet's distance from neighboring stars with 

 a sextant. 



The most important astronomical enterprise undertaken 

 in this country, during the last century, was the observa- 

 tion of the transit of Venus in June, 1769. Upon the 

 observations of this transit depended the more accurate 

 determination of the sun's parallax; from which is de- 

 duced the distance of the earth from the sun, and thence 

 the absolute distances of all the planets. Only three 

 transits of Venus are known to have ever been seen by 

 any human being. The first occurred in December, 1639, 



