London: Royal Society of London, 1850. Hardcover. First Edition. vii, -844, 13 pp. 4to. Library binding, tan leather spine with gold embossed titling. Interiors clean, ex-library stamp on title page, and occurring sporadically within. Numerous folding plates that illustrate articles. Pages were trimmed slightly when rebound. Very Good.
William Parson's (1800-1867) paper first identifies the spiral nebulae.
See also our #27509 by Parsons, credited as Lord Oxmantown, in his 1840 article "An Account of Experiments on the Reflecting Telescope" (Philosophical Transactions of the Royal Society of London, Vol. 130 for the Year 1840 Part II, pp. 503-527), which provided the technology enabling him to identify the spiral nebulae.