ARGO.--This large constellation extends much further south than Al-Sufi could follow it. The most southern star he mentions is ε Carinæ, but south of this are several bright stars. β Carinæ is 1·80 according to the Harvard measures; υ Carinæ, 3·08; θ, 3·03; ω, 3·56; and others. A little north-west of ι is the long-period variable R Carinæ (9{h} 29{m}·7, S. 62° 21', 1900). It varies from 4·5 at maximum to 10 at minimum, and the period is about 309·7 days. A little east of R Carinæ is another remarkable variable star, _l_ Carinæ (R.A. 9{h} 42{m}·5, S. 62° 3'). It varies from 3·6 to 5·0 magnitude, with a period of 35½ days from maximum to maximum. All the light changes can be observed with an opera-glass, or even with the naked eye. It was discovered at Cordoba. The spectrum is of the solar type (G). MUSCA, the Bee, is a small constellation south of the Southern Cross and Centaurus. Its brightest stars are α (2·84 Harvard) and β (3·26). These two stars form a fine pair south of α Crucis. Closely south-east of α is the short-period variable R Muscæ. It varies from 6·5 to 7·6 magnitude, and its period is about 19 hours. All its changes of light may be observed with a good opera-glass. APUS, the Bird of Paradise, lies south-east of Musca, and north of Octans. Its brightest star is α, about the 4th magnitude. Williams calls it "deep yellow." About 3° north-west of α, in the direction of the Southern Cross, is θ Apodis, which was found to be variable at Cordoba from 5½ to 6½. The spectrum is of the third type, which includes so many variable stars. TRIANGULUM AUSTRALIS, the Southern Triangle, is a small constellation north of Apus, and south of Norma. A fine triangle, nearly isosceles, is formed by its three bright stars, α, β, γ, the brightest α being at the vertex. These three stars form with α Centauri an elongated cross. The stars β and γ are about 3rd magnitude. β is reddish. ε (4·11, Harvard) is also reddish, and is nearly midway between β and γ, and near the centre of the cross above referred to. α is a fine star (1·88 Harvard) and is one of the brightest stars in the sky--No. 33 in a list of 1500 highest stars given by Pickering. About 1° 40' west of ε is the short-period variable R Trianguli Australis (R.A. 15{h} 10{m}·8, S. 66° 8') discovered at Cordoba in 1871. It varies from 6·7 to 7·4, and the period is about 3{d} 7{h}·2. Although not visible to ordinary eyesight it is given here, as it is an interesting object and all its light changes may be well seen with an opera-glass. A little south-east of β is another short-period variable, S Trianguli Australis (R.A. 15{h} 52{m}·2, S. 63° 30'), which varies from 6·4 to 7·4, with a period of 6·3 days; and all its fluctuations of light may also be observed with a good opera-glass. CIRCINUS, the Compass, is a very small constellation lying between Triangulum and Centaurus. Its brightest star, α, is about 3½ magnitude, about 4° south of α Centauri.