In thick and foggy weather a bell will be tolled by machinery , night and day, at intervals of half a minute.
The coloured light, being less powerful, may not he seen when the bright light is first noticed ; but the periodical revolution of the bright light will hi sufficiently distinguishable.  In thick and foggy weather a bell will be tolled by machinery , night and day, at intervals of half a minute.  At Arbroatb each of the light keepers has a house provided for his family.