In this paper, M. Blaise, Chairman of a committee of the International Association of Lighthouse Authorities, and the General Secretary of the Association, M. Pétry, comment on certain changes impending in the notation of luminous intensity and the range of marine lights. They conclude that the changes will be of benefit to navigators at sea and engineers.

In November 1925 the International Hydrographic Review published a report under the title ‘Observations of Visibility Lighthouses’. Since then notable progress has been made towards a standardization of methods. Relatively recently (1966), the International Association of Lighthouse Authorities (I.A.L.A.) published a recommendation for the notation of the luminous intensity and range of lights.