JF Ptak Science Books Post 2615
This beautiful illustration displays the 1774 sunspot theory of Alexander Wilson (1714-1786) of the University of Glasgow, who hypothesized that they were "holes" in the surface of the sun. The holes or cavities (A and B in this case) were an opening in the shining brilliance of the supposed surface of the sun, and revealing the true surface of the sun underneath the floating layer. This image is found in Amedee Guillemin's The Sun (1870 and 1875), found in Google Books/Hathi Trust (https://babel.hathitrust.org/cgi/pt?id=nyp.33433057659199;page=root;seq=224;view=plaintext;size=100;orient=0)
- Wilson, Alexander (1774) "Observations on Solar Spots", Philosophical Transactions of the Royal Society of London 64, part I.
'Others,' continues Cassini, 'have imagined that the centre of the Sun is an opaque dark nucleus, entirely covered by luminous fluid matter; that in this opaque body there exist volcanoes similar to Vesuvius and Etna, which throw out, from time to time, masses of bituminous matter, which find their way to the surface of the Sun, where they produce the effect of spots, in the same manner that a new island was formed in the Archipelago near Santorin and another near the Azores; that this bituminous matter is altered or decomposed by that which covers the surface and which gradually consumes or dissolves it, forming those nebulosities and transformations which are remarked in the spots; the latter disappearing when this bituminous matter is completely consumed or destroyed; that they appear again, however, at the same points of the solar disc, when the volcanoes throw up another lot of bituminous matter."
And just for good measure (and from the same source) here is an unusual comparison of what the Sun looks like from the surface of eight planets as well as asteroid Feronia (which I imagine must be the asteroid 72 Feronia discovered by CHF Peters in 1861) and from "Maximillian", which I have to admit escapes me. The interesting part here is that "Maximillian" and Feronia and Sylvia and Flora are all named in images or data boxes but are not mentioned or identified in the text, which means that they were known well enough in 1870 to not need any explanation, and were simply a part of a popular astronomical conversation on minor planets and asteroids. I'm not sure what the minor planet count was in 1875 or so but today the number is nearly 500,000 (numbered), of which about 20,000 have names.
And also the following, listing "Flora" and "Sylvia" in a planets list though they are 8 Flora and 87 Sylvia, asteroids in the main asteroid belt:
And the frontispiece, which names the Sun very non-marginally, as though it needed such an identifier:
Source: Amedee Guillemin's The Sun (1870 and 1875), found in Google Books/Hathi Trust (https://babel.hathitrust.org/cgi/pt?id=nyp.33433057659199;page=root;seq=224;view=plaintext;size=100;orient=0)