CALIFORNIA ACADEMY OF SCIENCES. 55 



weather was broken by a prolonged storm; and even in the 

 intervals of good weather succeeding it, the atmospheric 

 conditions were very unsatisfac tor j. 



A pressure of official duty, and the want of the mean-places 

 of many of the comparison stars, have prevented the reduc- 

 tion of the observations, although a preliminary examination 

 indicates their reliability. 



THE PLANETS MARS, JUPITER AND SATURN. 



During November, December and January, observations 

 of the physical appearance of these planets were made at 

 every available opportunity. Drawings of Jupiter and Mars 

 were made, and full notes kept in the study of Saturn. 



Saturn. 1 he position of the Encke division, plainly divides 

 the outer ring A into two slightly unequal annuli by being 

 nearer the outer than the inner circumference. This was 

 certainly the case at the preceding part of the ring, but at 

 the following part of the ring the division was apparently 

 nearer the inner circumference. This anomaly was doubt- 

 less occasioned by the sun shining full on the preceding 

 part of the ring, but at the following part the shadow 

 of the raised rim of the outer circumference of the B 

 ring was projected across and beyond the outer edge 

 of the Encke division upon the inner bright border of 

 the A ring. This reduced the apparent breadth of the 

 inner annulus of the A ring at that point, and makes it 

 appear narrower than the outer annulus. When the atmos- 

 phere was quiet this shadow made the breadth of the 

 Encke division greater at the following than at the pre- 

 ceding part of the ring. It was of course a very small dif- 

 ference, yet it was unmistakable under favorable conditions. 

 The dusky ring. While there were but two or three occa- 

 sions on which the inner circumference of the dusky ring 



