4 



160 Prof^ Backers Report on the U. ^S. Coast Survey. 



On the coasts of South Carolina and Georgia, the survey has 

 been in progress since 1S47. A base line has been measured on 

 Edisto island, and the primary triangulation commehced. A prelim- 



inary base has been measured near Savannah, and the triangulation 



of that river commenced. The triangulation of N. Edisto inlet 

 (harbor of refuge) is far advanced. The hydrography of Charles- 

 ton harbor and bar is nearly completed, and hydrographic recon- > 

 naissances have been made off the sounds of St. Helena and St. 

 Andrew. 



In the Florida section, a reconnaissance of the Florida reef, 

 keys, and adjacent main, has been completed from Cape Florida 

 to the Tortugas. The topography and hydrography of Key 

 \^est, and the adjacent islands and main, have been executed, a 

 reconnaissance made of Cape Canaveral shoals, and one of Cedar 

 Keys commenced. The work indicates a new channel for en- 

 tering the harbor of Key West. This section was entered on 

 in 1849. 



On the coast of Alabama and Mississippi; the primary and sec- 

 ondary triangulations, entered on in ISIGj are advancing. The 

 hydrography and topography of Mobile bay and the delta near ^ 

 the city are completed. 



In the section extending along the coasts of Louisiana and 

 Texas, entered upon in 1848, the primary and secondary triangu- 

 lations are in progress. The hydrography and topography of the 

 approaches and vicinity of Galveston are nearly completed. 



The parties sent to the coasts of Oregon and California have 

 been hampered for want of means to carry on the work. The 

 results, so far, have been — a general reconnaissance of the coast 

 of California, from Monterey to the mouth of Columbia River, 

 with charts and sailing directions — preliminary surveys of that 

 river and of the bays of San Francisco' and San Pablo — special ^ 



observations and reports on Cape Conception, (which has been ^ 



called the Hatteras of the western coast,) Cape Disappointment 

 and some other prominent points. 



From this general view, we may proceed to remark such stri- 

 king features or new observations, especially with reference to 

 their general scientific interestj as offer themselves in the report 

 of Prof Bache, under the respective heads of, Ist, the geodetic, 

 and 2d, the hydrographic, portions of the work. 

 • I. The correct measurement of a base line is the problem on 

 whose practical solution must rest the accuracy of the Survey, in 

 all its subsequent stages. Upon this head, the French scientific 

 journal, before quoted, justly remarks that '•many modes of pro- 

 cedure have been employed. The best, beyond all doubt, is that 

 of Professor Bachej who by a skillfully arranged apparatus, has 

 arrived at the most exact precision, and has succeeded in correct- 

 ing several defective determinations of his predecessors." 



f 



