Page:Star Lore Of All Ages, 1911.pdf/180

120 Aratos thus describes Capricornus:

This first pair, α1 and α2 Capricorni, respectively called "Prima and Secunda Giedi," are situated in the head of the Sea Goat. Burritt calls them "Giedi" and "Dabih" respectively, the former being the most northern of the two, and a double star. The star name "Dabih" is an Arabic appellation meaning, curiously enough, "the Lucky One of the Slaughterers," referring to the sacrifice celebrated by the Arabs at the heliacal rising of Capricorn.

The other wider parted pair of stars referred to by Aratos are δ and γ Capricorni, named respectively "Deneb Algiedi," meaning "the Tail of the Goat," and "Nashira" —"the Fortunate One" or "Bringer of Good Tidings." δ is an interesting star because it marks the approximate position of the discovery of the planet Neptune.

The discovery of Neptune is one of the most interesting episodes in the history of astronomical discovery, and a brief account of it is worth recording here.

Early in the 19th century it was found that the planet Uranus was straying widely from its predicted positions. Two astronomers, Adams in England, and Le Verrier in France, working independently and without each other's knowledge, endeavoured to ascertain the causes of the perturbations, basing their calculations on the supposition that an undiscovered planet beyond Uranus was the disturbing factor.

Adams began his work in 1843, Le Verrier in 1845. Adams communicated the results of his labour to the Astronomer Royal of England, but unfortunately the data were pigeon-holed. Le Verrier, who sent his calculations to Galle, the eminent German astronomer, was more fortunate. Galle turned his telescope toward the position in the sky determined by Le Verrier, and discovered the