56 CALIFORNIA ACADEMY OF SCIENCES. 



was sharply defined, yet without this condition, there were 

 no times when the extreme parts of the dusky ring were equally 

 distinct. And upon most occasions the preceding part of 

 the ring was the brighter. It became a question why this 

 appearance was so generally presented; whether it was in the 

 ring itself and would thus give a clue to its period of rota- 

 tion, or whether it was owing to the direction of the atmos- 

 pheric waves of disturbance as we see them in geodetic ob- 

 servations, whether due to peculiarities of the telescope or 

 the observers eye. Sometimes three observers made the 

 comparison before announcing the result : the atmospheric dis- 

 turbance might account for part of it. Changes of eye-pieces 

 did not correct the impression. Decided change of parts 

 was exhibited during one period of two or three hours. 



But upon more than one occasion the following part has 

 seemed the brighter without any doubt in the observer's 

 mind. 



It seems that one reason for the preceding part being- 

 brighter than its normal tone, must be in the additional light 

 reflected upon it from the illuminated body of the planet be- 

 ing brighter near the preceding limb, after apposition. 



I have not had an evening when the atmosphere continued 

 sufficiently and uniformly quiet to observe during the whole 

 night under equal conditions. 



The dusky ring, where it crosses the body of planet., does not 

 present a uniform tone of color, but the inner circumference 

 seems a little denser and darker than further out. This 

 might arise from a narrow dark belt on the body of the 

 planet just on the line of projection of the inne  circumfer- 

 ence on the body of the planet. 



There is across the white equatorial band, on the body of the 

 planet, a very narrow dark belt which I first noticed close to 

 the edge of the dusky ring. This belt moved very slowly 

 towards south during December and January. 



I have recorded also upon two occasions a narrow dark 

 line across the body of the planet in the dark part south of 



