The word " periscope" was first applied to this instrument.
Zeiss made a periscope 7 metres long, main tune 150 mm.
The modern practice is to take rapid observations rather than to keep the periscope above the water all the time.
In an ingenious periscope designed by Messrs.
Of these the most remarkable is the German Giant Periscope, two specimens of which exhibited in the collection of trophies in the Imperial War Museum, Crystal Palace, have excited considerable popular interest.