Compass has a half-life of only about 12 years, so a compass that contains 120 mCi of tritium when new will contain only 60 when it is 12 years old, 30 when it is 24 years old, and so on. Consequently, the illumination of the display will fade. Mariners' compasses can have two or more magnets permanently attached to a compass card, which moves freely on a pivot. A "lubber line", which can be a marking on the compass bowl or a small fixed needle, indicates the ship's heading on the compass card. Traditionally the card is divided into thirty-two points
Classical compass winds Meses, NNE), Caecias (NE), Apeliotes (E), Eurus (SE), "Phoenicias is also called Euronotos" (SSE), Notos (S), "Leuconotos alias Libonotos" (first mention, SSW), Lips (SW), Zephyrus (W), Argestes (NW) and "Thrascias alias Circius" (NNW). In many ways, Timosthenes marks a significant step in the evolution of the compass rose. Depending on how "Ventorum Situs" is dated, Timosthenes can be credited with turning Aristotle's asymmetric ten-wind compass into a symmetric twelve-wind compass, by introducing the SSW wind (Leuconotos/Libonotos) omitted by Aristotle and Theophrastus and assigning the compound "Euronotos" (already alluded to by Aristotle, no mention of Theophrastus's Orthonotos here) in place of