Observations of Twilight in respect of their Colour and Intensity. (First paper)

Abstract

In this report, are given the results of observation of twilight concerning with their colours and intensities, which have been carried out at Kyu-Honmaru, Tokyo, since Nov. 1931 to march 1932. The apparatus used for these Observations is consisted of three films, and each films have been coloured by three original colours of various concentrations. When the author observe a twilight, two or three pieces of them are properly combined and this conbined colours can be compared to a colour of twilight.
The author classified the twilights in several forms respecting of their colours and intensities from the results of observation, and further, investigated the relations between weather and “Dammerungserscheinungen”.