TY - BOOK ID - 138540534 TI - Report of the Secretary of the Treasury, on improvements in the light-house system and collateral aids to navigation. August 5, 1846. Read, and ordered to be printed. PY - 1846 PB - [Washington, D.C.] : [publisher not identified], DB - UniCat KW - Lenses. KW - Lighthouses. KW - Lightships. KW - Lighting. KW - Naval research. KW - Aids to navigation. KW - Lighthouse keepers. KW - Maintenance. KW - Repairing. UR - https://www.unicat.be/uniCat?func=search&query=sysid:138540534 AB - ER -