Page:Star Lore Of All Ages, 1911.pdf/219

Rh star of 2.4 magnitude. It was known to the Arabs as "Alphecca," which means the "bright one of the dish," referring to the resemblance of the constellation to a broken plate mentioned above. This star is also called "Gemma," and "the Pearl of the Crown," a title which Allen says has been occasionally transformed into Saint Marguerite.

Gemma is receding from our system at the rate of about twenty miles a second. Manilius thus refers to it:

This star marks the radiant point of the Coronids, a meteor shower visible from April 12th to June 30th. It culminates at 9, June 28th.

The Northern Crown contains the exceedingly interesting variable star lettered "R," which has been called "Variabilis Coronæ." It was discovered by Pigott in 1795 and varies with much irregularity from 5.8 to the 13th magnitude. There are only two other variables known to be of this type. To give an idea of the rapid changes of light in this star, it is interesting to note that on Sept. 21, 1910, its magnitude was 6.5, Oct. 17th it had declined to a 9.6 magnitude star, and by Nov. 2d it was only a dim star of the 12th magnitude.

The Greek word is the mnemonic word given by Young to assist the memory in locating the stars in this constellation, the stars in the Crown bearing in sequence these Greek-letter names.