Note 12 — THE STORM-CLOUD OF THE NINETEENTH CENTURY.

See below, on the different uses of the word 'reflection,' note 14, and note that throughout this lecture I use the words 'aqueous molecules,' alike of water liquid or vaporized, not knowing under what conditions or at what temperatures water-dust becomes water-gas; and still less, supposing pure water-gas blue, and pure air blue, what are the changes in either which make them what sailors call "dirty "; but it is one of the worst omissions of the previous lecture, that I have not stated among the characters of the plague-cloud that it is always dirty,[A] and never blue under any conditions, neither when deep in the distance, nor when in the electric states which produce sulphurous blues in natural cloud. But see the next note.