| 摘要 |
<p>An instrument for telling time at night includes a base that has a central aperture for sighting on Polaris and an annular hour scale inscribed on the base with the axis of the aperture as the center of the annulus, a calendar scale rotatable on the base about said axis and having indicia adapted to be aligned with the indicia on the hour scale, and a pointer rotatable about said axis and arranged to be removably secured to the calendar scale with its indicating edge in alignment with a selected mark on the calendar scale.</p> |
