Tom M. is right. The mystery drawing I posted a few days ago is of sunspots, observed and sketched on June 17, 1875 by Eteinne Leopold Trouvelot, a Frenchman by birth, then a resident of Massachusetts. Trouvelot rendered his finest sketches as chromolithographs that remain among the most exquisite astronomical images ever made.
Here is Trouvelot's drawing of the zodiacal light, observed on February 20, 1876, a phenomenon mentioned in last Sunday's Musing that light pollution has rendered virtually invisible in much of the developed world. (Can you identify the "stars" in the picture; for example, the two brightest objects near the horizon along the band of light? Yep, that's why it's called "zodiacal.")
Alas, Trouvelot is remembered more for bringing gypsy moths to America than for his astronomical drawings, a tragedy that resulted from his interest in entomology and which refuses to abate.
I thank SpaceTramp for making me aware of the New York Public Library Trouvelot website.