

74 CALIFORNIA ACADEMY OF SCIENCES. [Proc. 3D Ser. 



In the trigonometrical survey of Admiralty Inlet and 

 Puget Sound, during the approach of a southeast storm 

 which finally brought up dense clouds, a heavy squall and 

 rain, we observed a Scorpii (April 22, 1856,) with a three- 

 inch Fraunhofer telescope and astronomical eye-piece, power 

 about 70. The disappearance of the star was behind the 

 bright limb, and the record states that " the time denotes 

 the instant of the disappearance of the star after it had been 

 projected upon the body of the Moon for about two and one- 

 half seconds, certainly not less. The ruddy color of the star 

 showed distinctly upon the body of the Moon, and the 

 instant of disappearance was as accurately noted as if it 

 had disappeared behind the dark limb. Having once before 

 observed the same phenomenon, we were fully prepared 

 for it." 



In November, 1886, we presented a paper to the Cali- 

 fornia Academy of Sciences upon the occultation of a Tauri 

 on the twelfth of November. Three instruments were used 

 at the disappearance: two three-inch Fraunhofers, power 

 100, and a two-inch, power 55. The atmosphere was clear 

 and moderately steady, the stars showed signs of unsteadi- 

 ness, and the Moon's border appeared reasonably sharp. 

 The telescopes were not large enough for such observa- 

 tions, but an intervening house prevented the use of the six 

 and four-tenths inches Equatorial. 



The star was visible to the unassisted eye to within four 

 minutes of contact. When it was a few seconds from the 

 Moon's bright limb the star became invisible in the two-inch 

 telescope. In the three-inch Fraunhofers the star did not 

 disappear when it touched the apparent limb of the Moon, 

 but continued to move upon the disc until it was fully one 

 and one-half times the diameter of its spurious disc on the 

 Moon, when it disappeared with the instantaneity of such 

 phenomena. The star grew somewhat difficult to see after 

 it entered upon the factitious limb, but its reddish hue left 

 no doubt in the minds of the two observers, who differed 

 0.07 second in the time of its disappearance. They esti- 

 mated that it was three seconds of time on the limb. At 



