"Additional Remarks on Active Molecules" in The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science, 6, 1829, pp. 161-166.

1829. 1st Edition. FIRST EDITION of the second paper Robert Brown wrote on the subject of Brownian motion, the random motion of microscopic particles suspended in a liquid. Brownian motion is sometimes referred to as particle theory. In this paper, Brown discusses the observations of others, describes additional observations that eliminate several other possible causes of the motion, and responds to comments on his earlier paper; also included is a brief description of confirmatory experiments by Holland. The modern history of Brownian motion began in 1827 when Brown observed a continuous jittery motion of pollen grains in water through a microscope and wrote analytically about the phenomenon. He "saw that pollen grains of the herb Clarkia pulchella, while suspended in liquid, engaged in a continuous, haphazard, zig-zag movement" (Printing and the Mind of Man, 290). Based on his surprise at what he found, in this second paper "he continued experiments with other substances -- including inanimate bodies such as minerals and smoke -- and found that when the particles were very small, they all possessed this same motion" (ibid). This observation allowed Brown to rule out the hypothesis that the motion was due to the pollen being alive. The discovery of the physical process and subsequent mathematical explanations of Brownian motion "provided the first conclusive proof of the existence of atoms and molecules" (History of Physics: The Wenner Collection). Item #400

CONDITION & DETAILS: (8.5 x 5.5 inches; 213 x 138mm). [6], 472, [viii], 4. Brown paper: pp. 161-166. Ex-libris bearing only a small paper label at the spine and a discreet stamp on the title page. Bound in three quarter polished black calf over marbled paper boards. GIlt-ruled and lettered at the spine. Minor rubbing and scuffing; tightly and solidly bound. Slight age toning and foxing. Very good condition.

Price: $1,200.00