12 REPORT ON 



Lat. 24 38' N. 

 Long. 7 h 28 m 24 s W. 



On June 9th, after going to the extreme northern end of the bay, and pulling 

 a short distance up a creek, a place was found which, upon careful examination by 

 taking fore and back sights with a compass, seemed to be entirely free frojn all 

 local attraction. The land there is composed of fine white- sand hillocks, which. 

 are constantly being shifted by the wind, and are- so loose that a man will sink half- 

 way to his knees in walking over them. The only place where the surface was 

 sufficiently solid to admit of the instruments being set up was below high-water 

 mark, where the sand was wet. A complete set of magnetic observations, were made 

 there, which, however, were not as satisfactory as could have been wished, owing 

 to the magnets being disturbed by a stiff breeze which shook the instruments, 

 and from which there was no shelter. The position of this station was 



Lat. 24 39' 36" N. 



Long. 7" 28 m 26 S .2 W. 



It was on the east side of the creek (on its left-hand bank), at a place where there 

 i- a sharp bend in its course, and can easily be found by plotting the position, 

 given above, on the chart. 



SAN DIEGO- BAY, California. We were only in this harbor from 11 A.M. of 

 June 15th, 1866, till 11 A.M. of June 16th, and there was no time to swing the 

 ship. However, during the afternoon of the 15th a complete and very satisfactory 

 set of magnetic observations were made on shore at a spot on the beach near the 

 extreme southern end of the slightly rising ground at La Playa. The instruments 

 were set up just above high-water mark, and nearly due east of the U. S. Coast 

 Survey Astronomical Station. The true bearing of the light-house on Point Loma 

 was S. 3 56' W., and its distance exactly two statute miles in a direct line. The 

 spot was tested for local attraction by taking fore and back sights with a compass, 

 but none could be detected. 



The position of the station, according to the U. S. Coast Survey Chart, was 



Lat. 32 41' 58" N. 



Long. 7 h 48 m 52 9 .6 W. 



SAN FBANCISCO, California. The ship was swung in this harbor, on June 23d, 

 1866, in the usual manner. Her position at the time was lat. 37 48' N., long. 

 122 22' W. Joint XII on the after turret was 5.3 inches to port. While we 

 \\i re lying here the ship was swinging freely to the wind and tide. 



The observations taken on shore June 26th were made on the sand beach in a 

 cove on the east side of Yerba Buena Island, the instruments being set up just at 

 high-water mark, and about one hundred and fifty feet north of a long pier which 

 runs out over a mud flat. The place was tested for local attraction by taking fore 

 and back sights with a compass, but none could be detected. 



According to the U. S. Coast Survey Chart the position of this station was 



Lat. 37 48' 46" N. 

 Long. 8" 9 m 22,6 W. 



