Diagram in The Sphere during the inquiry into the Titanic disaster showing how ice blink reveals the presence of bergs underneath the water. The term 'ice blink', in common use with polar explorers describes the reflecting capacity of granulated portions of berg in contradistinction to the darkness of clear ice. Under favourable conditions, icebergs appear to glow with this 'blink', an effect which can be detected when the berg is on the far-distant horizon. Under unfortunate conditions, the berg may give forth no 'blink' and in the case of the 'Titanic' there was also the absence of a phosphorescent line round the berg which would have helped to indicate the nearness of ice. The depth below water is calculated on the assumption that six-sevenths of the berg are below the water-line.