OF THE UNITED STATES. S41 



Plan Jar putting into operation the Survey of the Coast of 



the United States. 



In my general |)lan of oi)cration for the survey, I men- 

 tioned, that tlie cstal)lislimcnt of two ol)servatoiies would l)e 

 necessary ; and I thought it |)ro|)er to prfjcure tlie instru- 

 ments, destined for them, of such a qiiahty and size, as to 

 be suital)le for a permanent national institution. For this 

 purpose, it would now be necessary to add only a mural 

 circle and a zenith sector, which, however desirai)le, I did 

 not venture to order, as their absolute necessity, in con- 

 nexion with the survey of the coast, was not so obvious as 

 that of the instruments procured. 



These observatories form the fixed points, to which the 

 survey, and particularly tlie naval part of it, is referred. The 

 selection of pro|)er jilaces, the erection of the buildings, and 

 the setting up of the instruments, will require some time. It 

 would therefore he desiral)le to begin with this part of the 

 general observation as soon as possilile. 



As they will be permanent scientific establishments, it will 

 be proper to decide whether the expense of their erection 

 shall be comprehended under those of the survey, or be 

 considered as separate. 



It will also be necessary to decide, where they shall be 

 erected. To procure the greatest advantage for the survey, 

 their positions should be as far north-east and south-west 

 as the very favourable position of the United States admits. 

 The same location atlbrds also the greatest scientific advan- 

 tages. Supposing one in the District of Maine and the other 

 in Lower Louisiana, nearly every celestial phenomenon ob- 

 servable fiom tiie tropic to the arctic circle, and within 

 about two hundred degrees of din'ercnce of longitude, could 

 be observed at one or other of them. The comparison of 

 their distance and position, as determined astronomically and 

 geodesically, would olfer the most rigorous proof of the sur- 



