On the Theory of Sunspots Proposed by Signor Kirchoff

Eileen Reeves (Department of Comparative Literature, Princeton University, Princeton, New Jersey, 08544) and Mary Posani (Department of French and Italian, The Ohio State University, Columbus, Ohio, 43221) provide a translation of Father Pietro Angelo Secchi’s classic work “Secchi A. Sulla Teoria Delle Macchie Solari: Proposta dal sig. Kircho ” as it appeared in Bullettino Meteorologico dell’ Osservatorio del Collegio Romano, 31 January 1864, v.3(4), 1– 4. This was the rst treatise to propose a particulate photosphere oating on the gaseous body of the Sun. The idea would dominateastrophysical thought for the next 50 years. Secchi appears to have drafted the article, as a response to Gustav Kirchho’s proposal, echoing early Galilean ideas, that sunspots represented clouds which oated above the photosphere. Other than presenting a newsolar model, noteworthy aspects of this work include Secchi’s appropriate insistence that materials do not emit the same light at the same temperature and his gentle rebuke of Kirchho relative to commenting on questions of astronomy.