Arcturus, the beautiful first magnitude star which glows so conspicuously in the constellation of Boötes, is, however, the main source of interest in these star groups. The star is popular for its appearance alone, for it is large and richly golden, and always easily located, but it is also of interest in a scientific way, for it has been found to be an extremely huge and glorious sun. Our sun placed at the same distance--145 millions of millions of miles--would shine as a faint and almost invisible star, yet Arcturus is so much larger than our sun that it drifts across our sky like a bowl of light. Arcturus is not only one of the largest but it is also one of the swiftest moving stars in the heavens. It moves so swiftly that it covers 100 miles in every second. This speed has caused it to be labeled a "runaway star." Although this star shoots through space at such an incredible rate of speed it has taken it _800 years_ to describe a space (as seen by our eyes) equal to the apparent diameter of the moon. This may give the reader some slight realization of the vast distance which separates us from Arcturus. But astronomers write it this way--"It has taken _only 800 years_ for Arcturus to describe a space equal to the apparent diameter of the moon," for the stars are so very distant that most of them do not seem to change their places in the heavens even in the course of many thousands of years. Amazing as the speed of Arcturus appeared to astronomers, they later discovered a star of the 8th magnitude in the southern hemisphere with even a greater proper motion. This star has moved the distance of the diameter of the moon in _220 years_, which means that it moves over a hundred times faster than the average star. But the late Professor Barnard of the Yerkes Observatory had the distinction of discovering a star with the largest proper motion known. The average star does not exceed one minute of arc in a thousand years but Professor Barnard's "runaway star" has the amazing proper motion of 10.3 seconds a year. In that length of time it travels twice as far as the average star does in a century! Scientists accomplish many wonderful, and most remarkable, deeds. Even the heroes who lived in the vivid minds of the ancient peoples dwindle into insignificance beside these men with their calm patience and brilliant seeking minds. "These mathematic men have thoughts that march From sphere to sphere and measure out the blue Of infinite space like roods of garden ground." --_Blackie._