M.-P.— Vol. I.] DAVIDSON— APPARENT PROJECTION, ETC. 89 



measure from the unsteadiness of the short line of inter- 

 vening atmosphere near the ground; and we then related 

 our experience at great elevations and over heated plains, 

 and urged the occupation of elevated and isolated stations 

 as the most effective means of avoiding an unsteady atmos- 

 phere in such costly and important observations. 



Observations of Solar Eclipses under Different 

 Atmospheric Conditions. 



Professor Dr. Schaeberle of the Lick Observatory ob- 

 served the total solar eclipse of October 9, 1893, at 6,600 

 feet elevation, on the western flank of the Andes in Chili. 

 He was eminently successful in all his observations on ac- 

 count of the extreme steadiness of the atmosphere. The 

 Sun's image, projected by the six-inch equatorial upon a 

 white cardboard, looked "more like an engraving than an 

 optical image." Aubertin, at the same station, said that 

 during the eclipse "the atmosphere was absolutely pellu- 

 cid"; he had had experience at Gibraltar in 1870, 



Our experience in observing the above eclipse at San 

 Francisco as a partial phase was the reverse of Professor 

 Schaeberle's, but very instructive. We condense the report. 

 The images of the Sun, and the micrometer thread were 

 projected by the 6.4-inch equatorial upon a white sheet of 

 paper. The apparent diameter of the Sun's image was 

 about twenty-two inches, 't'he atmosphere was unsteady, 

 and the border of the Sun was confused and blurred, and 

 lacked the solid or consistent brightness of the^disc. This 

 factitious border was about half a millimeter broad at the 

 least. The solar spots were confused and their details were 

 not distinguishable. As the time of first contact approached 

 we watched the predicted point of contact, not for the first 

 indentation of the Sun's disc, but for the first commingling 

 or overlapping, so to speak, of the factitious image of the 

 Moon's border with the factitious image of the Sun's border. 

 There first appeared a very faint darkening of the confused 

 and apparently expanded border of the Sun's limb. We 

 noticed it when it was about three millimeters long; the 



