CHAPTER XI 



WORK AT AN AMERICAN 

 OBSERVATORY 



IT is of a year's work at Flagstaff Observatory by Dr. 

 Percival Lowell and his assistants that I write the 

 year which ended in April, 1914. There is always 

 something that grips my imagination about the labours 

 of the American astronomers ; not only do they seize 

 upon whatever is of general interest, but they have a 

 positive genius for presenting results in the most 

 picturesque and pleasing form. At Flagstaff Obser- 

 vatory, then, during the year in question, the staff 

 gave systematic study to the planet Venus in order to 

 determine its rotation period. There is, as must be 

 well known, a great deal of uncertainty concerning 

 the time which Venus takes to rotate on its axis, 

 owing to its dense cloudy canopy which gives the 

 planet such a brilliant appearance concealing the 

 surface markings. At various times, observers have 

 suspected the presence of such markings, but Dr. 

 Lowell and his staff have discovered some of a spoke - 

 like nature, and not only have they discovered them 

 but they have confirmed them and completed their 

 detection. This is of the highest importance and 



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