p4p4 H. A. LENEHAN. 
cited. In almost every case there appears evidence of 
five successive stages of solidification and consequent 
retreat of the confined fused materials. Some of the 
definite objections to this theory of solidification from the 
outer parts inwards are discussed and criticised in detail. 
Saturn.—Professor W. C. Pickering of the Harvard 
University has discovered a tenth satellite of Saturn. 
The stages of the discovery from the first suspicion of its 
presence to the confirmatory evidence extended over some 
years. The discovery of the ninth satellite was also made 
at Harvard Observatory by Bond. The new satellite has 
a period of revolution of twenty-one days, or a little less 
than that of Hyperion, a near by satellite, which revolves 
around Saturn in twenty-one days and six hours; it has an 
estimated diameter of 200 miles, and just beyond even 
telescopic vision, and only the sensitive plate can catch it, 
the motion of the satellite is direct—against the hands of 
the watch viewed from the north in the plane considerably 
inclined from the plane of the rings. Observations of the 
satellites of Saturn and Uranus involving some hundreds 
of individual settings were made by Messrs. Frederick and 
Hammond with the 26-inch equatorial of the United States 
Naval Observatory during 1904. 
Secondary shadow of Saturn’s rings.—In the course ofa 
series of observations of the planet Saturn at Aosta, in 
Italy, during the latter part of 1904, a secondary shadow 
was seen projected on the rings. It was definitely noted 
that the new shadow was curved, but in the opposite 
sense to the primary. The curvature appears to vary 
irregularly, sharply defined on the side nearest the planet; 
the shadow becomes attenuated towards the exterior 
border, while on drawings made from December 22nd-27th, 
there is shown a bifurcation of the part of the secondary 
shadow which was projected on the inner ring. Taking 
