M.-P— Vol. I.] DA VIDSON— APPARENT PROJECTION, ETC. 73 



the higher gulches were driven over the observatory by an 

 incoming cold north wind from the Sierra Santa Inez. 



It is sometimes reported that stars become very unsteady 

 in a strong wind; yet we have determined micrometer 

 values by observations upon a close circumpolar star during 

 a fierce " norther." In geodetic observations between Mt. 

 Diablo and Mt. Conness, on a line of 143 miles across the 

 Sacramento Valley, we witnessed a strong norther blowing 

 down the valley and carrying vast quantities of dust across 

 the line of sight; but the wind did not reach the observing 

 station on the first day, when the heliotrope image was 

 fairly good, but was moved bodily by horizontal refraction 

 two or more seconds of arc from the normal direction. 



Observed Occultations of Red Stars at the 

 Bright Limb of the Moon. 



Referring now more particularly to the details of some 

 astronomical observations, we give a few instances from our 

 experience and that of others. 



On September 18, 1848, about seven and one-half hours 

 in the morning, we observed the occultation of a Tauri by 

 the bright limb of the Moon, using a telescope of probably 

 two and one-half inches aperture and moderate power. 

 The red star touched the bright limb, and we noted the 

 time mentally, because it did not instantly disappear. We 

 continued the watch until the star was unmistakably within 

 the apparent limb, when it disappeared instantly, about two 

 and a half seconds after the first apparent contact. We at 

 once submitted the case to our chief, R. H. Fauntleroy, 

 who said the disappearance was the true time of the occul- 

 tation, but he gave no explanation of the phenomenon. We 

 then submitted the observation to the Superintendent of the 

 United States Coast Survey, Professor A. D. Bache, who 

 wrote to the Royal Astronomer (Airy) on the subject. 

 The reply was that he personally had never observed the 

 phenomenon, but there were similar cases on record. He 

 gave no explanation. 



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