Correspondence regarding ball lightning observation, 10 October 1946

This document is a letter dated October 10, 1946, written from Ludvika by Helge Tuxen-Mayer to an unnamed recipient. The letter serves as a response to a previous communication regarding an interesting observation made by the recipient. Tuxen-Mayer provides an analysis of the observation, comparing it to the characteristics of ball lightning (klotblixt). He references an enclosed publication (pages 89-95) to support his assessment, noting that the recipient's description of the object's color, size, and altitude (2 meters above the ground) aligns well with known ball lightning phenomena. The author explains the physical nature of ball lightning, describing it as a very hot gas concentration in a metastable state. He details how the object's color changes from white or bluish-white to yellow, orange, and sometimes red as it cools. He further explains that the object eventually disappears with a sharp crack or bang when the gas concentration becomes too cold and its stability is lost. Tuxen-Mayer addresses specific details of the recipient's report, noting that the object's continued movement in its trajectory does not align with typical ball lightning behavior. He suggests that there must have been clouds on the day of the observation and asks if any thunder was heard. He also mentions that ball lightning can potentially form without noise through a slow ionization of the air. Finally, he notes that the absence of any physical fragments or marks on the ground further supports the conclusion that the phenomenon was ball lightning. He concludes by stating that while ball lightning is rare, the weather conditions in September and early October could be conducive to such occurrences.