ount of the number that could be seen through Herschel's famous telescope made it twenty thousand. The great telescopes more recently made would probably show as many as forty or fifty millions."
"I should think," said May, "that it would be awful tiresome to count so many things just alike, and that the man would often count the same one over and over without knowing it, and would never be sure that he had counted right."
"They are not all alike," said the Professor. "They differ greatly in brightness, and to some extent in color, and in other particulars. They have been divided according to their brilliancy into sixteen classes or magnitudes. The fifteen brightest stars are said to be of the first magnitude, the fifty next of the second, and so on to the sixth, which comprises the faintest stars visible to the unassisted eye. The brightest star of all visible in our latitude is the dogstar, which gives four times as much light as any other. In every age of the world there have been learned men