ASTRONOMY. 411 



tioDS, some of which may possibly be of periodical character. The red 

 spot has now been followed since 1S78. Daring the last three years it 

 has given a rotation period of 9^ 55™ 39-»l, which has been steadily 

 maintained throughout each opposition, subject to some minor disturb- 

 ances partly due to errors of observation. The first few years of its ex- 

 istence it showed an increasing retardation of motion, which lengthened 

 the period from 9^ SS"' 34« to that already quoted, but, contemporarily 

 with the decay of the spot in 1882, the velocity ceased to slacken, and 

 the results accumulated during the past few oppositions, prove it to 

 have been equable in a marked degree. 



With reference to the equatorial white spot some striking phenomena 

 have been presented during the past winter. Between October 4, 1884, 

 and January 13, 1885, its motion appears to have increased in an alarm- 

 ing ratio. The spot continued to rush on far in advance of its computed 

 places, and all the while exhibited a more brilliant appearance than at 

 any preceding epoch since the autumn of 1880, when it first came under 

 systematic observation. The form and appearance of the spot have been 

 so special as to prevent any confusion in mistaking it for other white 

 spots in nearly the same latitude. Between October 4 and January 13, 

 1885, the rotation period was 9^ 49"" 51^-95, but the great increase in 

 velocity evidently occurred towards the end of ISTovember. Between 

 November 21, 1884, and January 13, 1885, the period was only 9^ 49'" 

 38«-45, or 34 seconds less than the mean period of 9^ 50" 1S«'25 shown 

 by the same spot during the two preceding years. 



" Of the new features presented during the last few months the most 

 striking are : " (1) The appearance of large, bright spots indenting 

 the north edge of the great northern equatorial belt. (2) The outbreak 

 of dark, reddish spots, elongated in longitude, upon the narrow belt 

 which became visible in 1882, immediately outlying the great belt. One 

 of the most conspicuous of these new spots is about 10,000 miles long. 

 (3) The fading away of the west shoulder of the depression north of the 

 red spot. 



Professor Young remarked * a peculiar white cloud of oval form par- 

 tially covering the " red sj^ot," in March, 1885. This veil was almost 

 concentric with the spot, leaving visible only a narrow ring of the red 

 substance not more than 1^" to 2" in width. The outline of the 

 cloud was for the most part sensibly smooth and regular, but at the 

 preceding end there was a little projection nearly cutting across the red 

 ring. The white cloud was not brilliant, but was very nearly of the 

 same tint as the white belt on which the red spot lies. 



At the Dearborn Observatory, Chicago, the systematic observation 

 of the markings on Jupiter has been continued by Professor Hough : 

 his results are given in full in his annual report for 1885, which contains 

 sketches of the planet on November 7, 1884, and February 27, April 20, 

 and May 15, 1885. 



* Ohservatory, vin : 172. 



