284 Astronomical Notes. 



with this theory. We may say this is a theory which had its 

 origin in our own mind, but on looking up astronomical 

 literature we find that it is not new. 



Saturn. 



This planet revolves round the sun in a little less than 

 29I years, and being high in altitude in the constellation 

 Taurus, also in the most favourable position for studying its 

 rings, which are quite unique in the Solar system, I may 

 explain that during each revolution of the planet in its orbit 

 the rings, which are comparatively thin, are turned twice 

 edgeways towards the Earth, and twice during each revolu- 

 tion they are turned with the flat sides towards the Earth in 

 a slanting or oblique position. This latter position, which 

 occurs periodically in a little less than fifteen years, is the 

 position in which the rings have been in during the past 

 winter. I have observed them on a number of occasions during 

 that time with the 6-inch refractor, but there has not been 

 many evenings when atmospheric conditions were the most 

 favourable for fine seeing. On the gth of February, 191 3, 

 seeing was exceptionally fine, being free from wind and 

 atmospheric disturbance. The system of rings was very 

 fine. The cassini division easily seen at the ansea, and the 

 line traced all the way round the front of the Ball, also the 

 shadow of the ball on the rings, and two belts round the globe 

 near the equator. On the same evening I had an exception- 

 ally fine view of that grand nebula in Orion, the field of the 

 telescope being flooded with light. This is an object that I 

 have observed many times, but I thought when looking at it 

 that I had never seen it so brilliant and beautiful before, with 

 the " Trapezium " shining out crisp and clear. 



