PROGRESS OF ASTKONOMV I'OK 181tl AM) l^ilL'. 719 



In ;i discussion of tlic moon's aluiospheic Mr. K'aiiyard cvincsscs 

 tlie o))inion that tlu' moon can not lia\c an atmos|)licrc one two-tlioii- 

 sandtli part as dense as that of rlic earth at seak'xcl. It must, how- 

 ever, be i<'Uieml)ercd that, were our atmosphere transferred to the 

 uu)on. its density woukl only be one sixth what it is on the earth. 



IMofessor Weinek, of I'laji'ue, who has been niakin<i' a spe(;ial study 

 of the Lick ])lioto<^iaphs of tlu' moon, lias (h'tectcd several new rills 

 and craters on the n(\nati\es. 



Mars. — .Mars was in opposition to tlic sun on >Vu.irust .1. iSHi*. and 

 thouiih tlu' planet was also at this t inu' \'eiy fa\<)ial)l\' situated as re- 

 ,iiards its ])roxiinity to the eartii, its <;reat southern declination was a 

 sei'ious impediuHMit to observation in the nruthern iu-misphcre. At 

 the llar\ard ()l>ser\Mlory station. Aie(|uipa, Peru, the planet was, how- 

 ev«'r. aliJiosr in the /enith, ami full ad\antaj;e was taken of this by I'rof. 

 AV. II. Pickering and his assistants. Many of Scliiaparelli's canals were 

 identified: some were seen doul>le. and marked chanii^s were detected 

 in progress in various i>aitsofthe planet, especially in the neighbor-hood 

 of the Lt(ciis sdH.s or Terby sea. Prof, i^ickering and other observers 

 detected a number of bright while spots besides the polar snow cap. 



In an article in the ^Farch ii\}\\\\H}r of LWstroiioiiiir. iStH, b'lamuiarion 

 descriltes various changes in the topogra|>hy of Mais, the most striking 

 (»f whieli are also in connection with the 'rerl)> sea. Drawings are 

 given of its appearance ill 1S77, 1S7!>. ISSI. and LSHO; brietl.N, it seems 

 to ha\e undergone cleavage, and while some former ••aftlueiit canals" 

 have <lisapi>eared. other new ones lia\e d<'\elo[)<'d. The strait called 

 llerschel ii has been transformed into a straight double canal. 



-lUl'tTER: Di.scorcri/ of <t JiJ'lli sat(Ui1>'.—'V\w most interesting as- 

 tronomical event of the sear IS'.L* w as tlu' discovery by Barnard, with 

 the .'](j-inch Lick (Mpuitorial, on Sei»tember 0, of a fifth satellite of the 

 phinet Jupiter. 



I-'oUow ing is Prof. Harnard's own ac(M)Uiit of his dis('ov<'ry, in describ- 

 ing his search for new objects in the Astrcuiomical .lournal: 



N(»t hing of sjx'cial importance was encountered until the night of 

 September t). when, in carefully examining the immediate region of the 

 planet Ju))iter, I detected an exceedingly small star close to the planet 

 ami near the third satellite. I at once measured the distance and jh)- 

 sition angle with reference to sateilite ill. 1 tlu'U tried to get meas- 

 ures referred to. hi) )iter, but found that one of the wires had got broken, 

 and the other loosened. Hefore anything further could be done the 

 object disai)peared in the glare about -hipiter. 'riiough I was ])ositive 

 the object was a new satellite, 1 had only the one set of measures, w liicli 

 was liardly ]>roof enough for aiinonncement. 



r rei>la(M'd the wires the ii(»\t morning. 'IMie next night with tli(^ 

 great teleseoi)e, being IM'of. Schaeberle's. he \-er>- kindly ga\(' tlu' in- 

 strument iij) to me, and I had the pleasure of veiilyiiig the discovery, 

 and secured a good set of measures at <'loiigatioii. 



.lust what tlu' magnitude of the satellite is it is at present quite im- 

 possible to tell. Taking into consideration its position, however, in the 



