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254 purification by bathing at the junction of two streams. This would be where the stream branched out, which shows clearly a similarity of representation respecting this star between two widely separated peoples.

β Libræ was known by an Arab name signifying the northern claw. It is the only naked eye green-coloured star in the heavens, and is an interesting variable. Eratosthenes called it the brightest of all the stars in the Scorpion, that is in the double constellation, and Claudius Ptolemy gives it as equal with Antares, the brilliant first magnitude star in the heart of the Scorpion. As it is now a full magnitude fainter than Antares, it must have lost much of its pristine brilliance, though there is a possibility that Antares may have increased in brilliance. Beta has a Sirian spectrum, and is said to be approaching our system at the rate of six miles a second.

δ Libræ is a variable star of the Algol type, discovered by Schmidt in 1859, with a period of nearly two days and eight hours.

The constellation is easily identified as its four principal stars form a fairly conspicuous quadrilateral figure. About twenty-two centuries ago this constellation coincided with the sign Libra, but owing to the Precession of the Equinoxes it has advanced thirty degrees on the ecliptic, and the constellation Scorpio is now in the sign sagittarius and so on.