For diving in turbid water, 45-watt Sodium hand lamps became the preferred choice.
2.
The Siebe Gorman & Company introduced a 250-watt mercury vapor hand lamp in 1919 that could produce as much as 18, 000 candles.
3.
For many years, the islanders had no means of contacting the mainland in emergencies other than signalling with hand lamps and hoping that someone would see them.
4.
In absence of any other signal, all trains were obliged to stop at the board to await instructions; the dispatcher, however, could show a green hand lamp to an approaching train, which allowed its crew to ignore the stop board.
मोबाइल