(London, W. Bulmer and Co., 1801). 4to. No wrappers as extracted from ""Philosophical Transactions"" 1801 - Part I. Pp. 265-318 and 2 folded engraved plates. Wide-margined. A few small marginal brownspots.
First appearance of an remarkable paper containing an extensive set of observations on the sunspots intermingled with what Herschel called ""ideas that obtruded themselves"" at the time of observation.""Herschel's interest in the sun was naturally stimulated by the realization that, of all the stars, it alone is close enough for detailled examination. he was aware of the various existing theories of the physical constitution of the sun. In a long paper published in 1795 he mentions some of them before his own observations...In 1801, in a second long paper (the paper offered here) in which he arranged his observations according to relevant physical questions, he modified his earlier account of the sun to include in its constitution an interior layer of dark clouds not unlike our own, this layer serving to shield the solar inhabitants from the exterior, luminous layer.