| 摘要 |
582,691. Magnetic compasses. NEILL & CO. (SHEFFIELD), Ltd., J., and EDWARDS, A. Sept. 9, 1944, No. 17242. [Class 97 (ii)] A liquid-filled compass has a moulded thermoplastic case 1, 2, the cover 1 being transparent and cup-shaped to retain an airbubble 13 which can serve as a levelling indicator or can be displaced and trapped by a depending rim 15. A lens 17 can be moulded in the cover and also scales of degrees or other indicia. |
