- One of the small southern constellations introduced by the Frenchman Nicolas Louis de Lacaille after he mapped the southern stars in 1751–52. Lacaille wrote that the constellation represented a pendulum clock beating seconds, as used for timing his observations. Lacaille introduced it on his first chart in 1756 under the French name l’Horloge, but this was Latinized to Horologium on the second edition of 1763.