THE STABS. 163 



of its motion is over eight seconds of arc 

 yearly ; and an idea of the vast distance of the 

 stars may be obtained by the statement that it 

 would take 200 years for the star known as 

 Gould's Cordova Zones, V Hour 243 to move 

 over a space equal to the moon's diameter. 

 Important observations have been made on the 

 stellar motions, and on their bearing on the 

 structure of the Universe, by various astron- 

 omers, including J. C. Kapteyn and Ludwig 

 Struve (born 1858), son of Otto Struve; but 

 these must be reserved for a later chapter. 



Richard Anthony Proctor, born at Chelsea, in 

 London, in 1837, graduted at Cambridge in 1860. 

 For the next twenty -eight years he earned his 

 living by publishing many volumes on astronomy, 

 popular and technical, fifty-seven having appeared 

 at the time of his death, which took place at 

 New York on September 12, 1888. Notwith- 

 standing the vast amount of work bestowed on 

 his books, his original investigations were per- 

 manent contributions to astronomical science. 

 In 1870 he undertook to chart the directions 

 and amounts of 1600 proper motions. While 

 engaged on this work, it occurred to him that 

 it would be " desirable and useful to search for 

 subordinate laws of motion." He found, from 

 the laborious process of charting, that five of 



