A galvanometer housed in a brown wooden box. Used as a submarine telegraph test apparatus. Box is hinged on one end and opens to become the stand for the galvanometer. (The key for the latch is lost ...
Discover world-changing science. Explore our digital archive back to 1845, including articles by more than 150 Nobel Prize winners.
Some results have been hidden because they may be inaccessible to you
Show inaccessible results