76 CALIFORNIA ACADEMY OF SCIENCES. [Proc. 3D Ser. 



the Lassell Reflector of thirty-four inches, and Mr. Lewis 

 with a refractor of three and three-fourths inches. Mr. 

 Turner noted : "No projection ; disappeared instantaneously 

 at bright limb." Mr. Lewis noted that " the star touched the 

 limb of the Moon five seconds before the observation, and 

 was sHghtly inside the Hmb." It appeared " as a brilliant 

 spot in the Moon, and disappeared suddenly at the time 

 given above." In the same number of the " Observatory " 

 where this report is made Mr. Ranyard says that " in the 

 case of Jupiter there are instances * * * where one or 

 two stars have apparently been seen through the limb of the 

 planet. There are such a number of these observations that 

 we cannot doubt the planets have not a sharp limb; they 

 seem to be surrounded by an atmosphere of great depth, or 

 rather a gaseous envelope, in which clouds or dusty matter 

 float in irregular masses." This is an extraordinary state- 

 ment, and, in our judgment, based upon a misconception of 

 the cause of these phenomena. 



The outline of any cloud system at such enormous dis- 

 tances from the Earth as Mars, Jupiter and Saturn would 

 subtend so minute an angle that the outline of the planet 

 would necessarily appear sharp, even if the assumed cloud 

 were irregularly distributed. The Sun's outline appears 

 remarkably sharp when our atmosphere is steady, and yet 

 we know that extraordinary disturbances of the solar 

 surface, far beyond our experience, are constantly taking 

 place. 



On May 10, 1895, Mr. John Tebbutt observed the occul- 

 tation of Antares at Windsor, New South Wales. The 

 steadiness and definition of objects were reported very sat- 

 isfactory. The instrument was an eight-inch objective, 

 with a magn. power of 74, and "Antares, quite brilliant to 

 the last moment, was closely watched till it came into con- 

 tact with the bright limb; but then, instead of instantly 

 disappearing, it seemed to cut its way into the disc during 

 two or three seconds, and vanished instantaneously. The 

 reappearance of Antares (62 1-3 minutes) later at the dark 

 limb was remarkably instantaneous." It should be noted 



