410 SCIENTIFIC RECORD FOR 1885. 



" Proctor's value is clearly too large, a comparison of the mean longi- 

 tudes obtained for the Kaiser Sea with his period showing a steady de- 

 crease for successive oppositions ; the only observations which stand 

 conspicuously out from the rest being those of Hooke, upon which he 

 had based his determination. There can be no doubt that Professor 

 Bakhuyzen's value is a distinct improvement upon the earlier ones, and 

 that its uncertainty lies only in the second place of the decimals. A 

 table for computing the time of transit of the iDrime meridian over that 

 meridian of Mars which passes through the earth's north pole, com- 

 pletes the memoir. 



Professor Bakhuyzen supplies also a short note as to changes on the 

 surface of Mars. The most conspicuous of all the markings on the 

 planet's surface has always been the Kaiser Sea ; but the drawings of 

 Schroeter and Herschel, as Dr. Terby has already pointed out, exhibit 

 a second marking near it, nearly as conspicuous, and very similar in 

 shape and size. There can be no doubt that the only modern represent- 

 ative of this spot is Enggins Inletj Schiaparelli's Gyclopitm, a narrow 

 streak, by no means easily observed, and now entirely unlike the Kaiser 

 Sea, in shape. Professor Bakhuyzen also considers that there is suffi- 

 cient evidence for thinking that Schroeter on several occasions ob- 

 served Schiaparelli's Lmstrygonum — one of the most difficult objects on 

 the planet — whfch could scarcely have been the case had it not been 

 much more conspicuous than it has been of late years. These changes. 

 Professor Bakhuyzen thinks, lend a high degree of probability to the 

 theory that certain districts of Mars are covered by liquid." {Nature, 

 November 12, 1885.) 



Jupiter : Mr. W. F. Denning has given in Nature (32 : 31-34, May 

 14, 1885) a summary of recent observations of the markings ojx Jupiter, 

 with resulting rotation periods, &c. The great red spot has surprised 

 us by its extended duration. As early as 1882 it lost such a consider- 

 able depth of tone that obliteration seemed imminent, but it has lingered 

 on, until now its existence appears likely to be indefinitely prolonged, 

 though under visible conditions far less imposing than at an earlier 

 stage. All that at present remains of this remarkable formation is a 

 dusky elliptic ring, darkest at the following end, and only well seen 

 under good definition. Whether this ellipse is identical with similar 

 appearances delineated by Dawes in 1857, Huggins in 1858, and Gled- 

 hill in 1869, 1870, and 1871, is involved in doubt, because of the lack of 

 intermediate observations. We have no definite information as to what 

 became of the various objects alluded to. It is very possible that they 

 severally represent an object of considerable permanency. The changes 

 such as observed may have been induced by atmospheric interference. 

 There is every indication that the dense vaporous envelopes of this 

 planet are rapidly variable, especially in the zone included by the two 

 equatorial belts, and .that the chief features undergo singular fluctua- 



