178 Observations of the 



fine ; still no satellite could be detected. It was remarked, 

 however, that a star of about the sixteenth magnitude which 

 appeared in the field got almost completely obliterated when 

 it approached within six diameters of Mars. 



The moonlight now began to interfere with the search, 

 and advantage was taken of the interval to try a series of 

 experiments for improving the definition by cutting off 

 some of the extreme rays from the mirrors. Increased 

 sharpness was thus obtained, but at the expense of so much 

 light that the full aperture was always employed afterwards. 



On the morning of November 5th, between 2h. 15m. and 

 2h. 30m., Mr. Turner got a glimpse of a speck of light in 

 the position indicated by the ephemeris; but clouds soon 

 came up, so that it could not be seen long enough to know 

 whether it was following Mars or not. On the evening of 

 this day the observations extended from 9h. 0m. till llh. 30m., 

 but nothing was then seen. 



On November 6th the night was fine, with occasional 

 hazy intervals. The best position was computed to occur a 

 little before midnight. At about half-past twelve Mr. Turner 

 got a few momentary views of the satellite ; he sometimes 

 thought it blight enough to measure its position. Nothing 

 like continued vision, however, could be obtained for even a 

 few seconds, so that all attempts at measurement were unsuc- 

 cessful. I also took part in the observations of this night, 

 but at no time couJd I see the satellite. 



On November 13th the night was cloudy and wet till 

 lOh. 15m., when it cleared up ; soon afterwards Mr. Turner 

 saw the same object as on the 4th and 6th instants. Attempts 

 to measure the place were made with the micrometer, but 

 without success. According to estimation, however, the 

 position angle was 54°, and distance 2|- diameters from the 

 following limb of Mars. The observer remarks : — " The 

 speck seen had not a sharp appearance like a small star, but 

 a nebulous look, and I at once recognised it as the same 

 object seen on the previous occasions. It seemed to scarcely 

 change its position with regard to the planet, though the 

 motion was plain enough ■ when referred to a twelfth 

 magnitude star, which was at the same time in the field. 

 I feel certain this is no optical illusion." 



The night of November 15th was very clear, but the 

 images were unsteady. At 8h. 55m. the satellite was seen 

 at an estimated distance of 2} diameters from the preceding 

 limb of Mars, and angle of position 235°. I also observed the 



