(London, Taylor and Francis, 1870). 4to. No wrappers as extracted from ""Philosophical Transactions"" 1869 - Vol. 159 - Part I. Pp. 1-110, textillustr. a. 2 plates.
First printing of one of the first papers dealing with the photography of the sun. De La Rue invented the ""photoheliograph"" for the Kew observatory, and by means of it the first solar light-pictures of real value were taken. The conclusions arrived at by photographic means at Kew were communicated to the Royal Society in a series of papers drawn up jointly by De la Rue, Balfour Stewart, and Benjamin Loewy. They influenced materially the progress of thought on the subject they were concerned with and initiated astrophysics.