‎"SIEDENTOPF, H. und R. (RICHARD) ZSIGMONDY. - THE INVENTION OF THE ULTRAMICROSCOPE.‎
‎Ueber Sichtbarmachung und Grössenbestimmung ultramikroskopischer Teilchen, mit besondrer Anwendung auf Goldrubingläser.‎

‎(Leipzig, Johann Ambrosius Barth, 1903). Without wrappers.. In ""Annalen der Physik. Vierte Folge. Bd. 10. No 1. (Entire issue offred). With halftitle to vol. 10. 224 pp. and 1 folded plate. Seidentopf & Zsigmondy's paper: pp. 1-39 a. textillustrations. The issue punched in inner margin after cords. 3 small stamps in the text.‎

Reference : 44237

‎First printing of the paper in which Zsigmondy describes his invention of the Ultramicroscope, by which is became possible to see the Brownian movements of molecules. His microscope is still of great importence in colloid studies, but in most fields where great magnification is required, it has been outdistanced by the electron microscope.""Zsigmondy was a figure of paramount importance on colloid chemistry during the first quarter of the twentieth century. His receipt of the Nobel Prize in 1925, for invention of the ultramicroscope and his work on colloids was the first time this fledgling science had been so honored. In 1926 work by J. B. Perrin and Theodor Svedberg that followed directly from Zsigmondy’s achievement was recognized by the Nobel Prizes in physics and in chemistry, respectively. No Nobel Prize since then has been awarded for work solely in colloid chemistry. (DSB).The offered issue contains another importent paper by MAX ABRAHAM ""Prinzipien der Dynamik des Elektrons. Pp. 105-179. In 1902 Abraham said ""It now becomes necessary to base the dynamics of the electrons from the outset on electromagnetic considerations"" In 1903 (the paper offered) he published his main detailed article on the rigid electron""(Pais in Subtle is the ord"" pp. 157 ff.""The ultramicroscope is form of microscope that reveals the presence of particles that cannot be seen with a normal optical microscope. Colloidal particles, smoke particles, etc., are suspended in a liquid or gas in a cell with a black background and illuminated by an intense cone of light that enters the cell from the side and has its apex in the field of view. The particles then produce diffraction-ring systems, appearing as bright specks on the dark background.‎