522 THE POPULAR SCIENCE MONTHLY 



paling Jupiter when seen near him by almost the like amount. Her 

 incomparable splendor is partly the result of propinquity; nearness to 

 ourselves and nearness to the sun. Relatively so close is she to both 

 bodies that to show she does not need the abetting background of the 

 night, but without waiting for the sun's withdrawal may nearly always 

 be seen in the daytime in clear air if one knows where in the sky to look. 

 Situate about seven tenths of our own distance from our common giver 

 of light and heat, she gets about double the amount of solar radiation 

 that falls to our lot, so that her surface is proportionately brilliantly 

 illuminated. Being also relatively near us, she displays a correspond- 

 ingly large disk. 



Nevertheless, until recently astronomic inquiry regarding her has 

 proved singularly baffling. The beauty of her face was equaled only 

 by the blankness of her expression. Hers proved one of those counte- 

 nances that dazzle on a first glance, to tell you nothing on a second. 

 From the time when Galileo first saw her phases, little was learned of 

 her for two centuries and a half, and even the little she seemed to show 

 proved misleading. The few traits thought to be discerned there were 

 so faint and fugitive that, while some observers deemed them substan- 

 tial, others ascribed them in whole or part to cloud. A cloud-en- 

 shrouded planet Venus in consequence was considered to be ; a covering 

 not so much for her own sins of commission as for the sins of omission 

 of observers to see. 



It was not until Schiaparelli attacked the subject that any real 

 light Avas shed on her who reflected so much. Through a new departure, 

 by choosing daylight for his observation time, that most eminent ob- 

 server first solved one riddle she had read astronomers so long, the 

 length of her day. Hitherto she had been scanned chiefly for a few 

 moments at twilight and the recurrent aspect her disk presented on 

 successive days had been for much in imputing to her a rotation not 

 differing substantially from the earth's in length. Schiaparelli's 

 method allowed of repeated scanning during several hours at a stretch 

 and in this manner he learned that the periodic punctuality of the same 

 features night after night was not because they managed so nearly to 

 keep pace with our own, but because they failed to move at all in the 

 meantime. In other words, her day must be immensely long. He then 

 critically examined the older observations and found that they could 

 all be thus explained. Six years later he repeated his observations and 

 with the like result. 



In 1896 the subject was taken up at Flagstaff. Very soon it became 

 evident that markings existed on the disk, most noticeable as fingerlike 

 streaks pointing in from the terminator, faint but unmistakable from 

 the positional identity of their successive presentation. A projection 

 near the south cusp was also clearly discernible, as well as two others, 

 one in mid-terminator, one near the northern cusp. Other dark mark- 



