17 February 1911, Vienna, IX. Berggasse 19

Dear friend,

I see you don't believe me; you seem to think I have my cycles and that suddenly, at certain intervals, I feel the need of looking at the world through rose-coloured spectacles. I see I must give you further details. In the daytime there was no smell of gas because when the cock was closed none escaped. But in the evening from ten to one, when I was working under the desk lamp, the gas escaped from the loose joint between the metal pipe and the rubber tube connected with the lamp. On inspection, a flame shot out of this leak. I smelled nothing because I sat swathed in cigar smoke while the gas gradually mixed with the atmosphere. The result was strange headaches which set in, or increased, in the evening when I was working, and by day annoying lapses of memory, which obliged me to keep asking myself: Who said that? when did that happen? etc. I am still very proud of