Randomness, uncertainty, and lack of regularity had concerned savants for a long time. As early as the seventeenth century, Blaise Pascal conceived the arithmetic of chance for gambling. At the height of positional astronomy, mathematicians developed a theory of errors to cope with random deviations in astronomical observations. In the nineteenth century, pioneers of statistics employed probabilistic calculus to define “normal” and “pathological” in the distribution of social characters, while physicists devised the statistical-mechanical interpretation of thermodynamic effects. By the end (...) of the century, a probabilistic worldview—as historians Lorrain Daston, Theodore Porter, and Stephen Stigler. (shrink)

In this paper, we examine the pioneering research on electronic noise—the current fluctuations in electronic circuit devices due to their intrinsic physical characteristics rather than their defects—in Germany and the U.S. during the 1910s–1920s. Such research was not just another demonstration of the general randomness of the physical world Einstein’s work on Brownian motion had revealed. In contrast, we stress the importance of a particular engineering context to electronic noise studies: the motivation to design and improve high-gain thermionic-tube amplifiers for (...) radio and wired communications. Engineering scientists’ endeavors to understand electronic noise started in 1918, when Walter Schottky at Siemens formulated a theory of “shot noise,” current fluctuations owing to the random emissions of discrete electrons in a tube. Schottky’s theory was revised and experimentally tested at Siemens, General Electric, and AT&T during the 1920s, leading to the discoveries of several other types of noise and an increasing interest in the thermal fluctuations in electronic circuits. In 1925–1928, J.B. Johnson and Harry Nyquist at Bell Labs developed a theory of thermal noise for any electrical resistor at a non-zero temperature. Although these studies were initiated to chart the fundamental performance limit of electronic technology, they ended up assisting the empirical determination of individual electronic components’ characteristics. (shrink)

This paper aims to cast light on the reasons that explain the shift of opinion—from scepticism to realism—concerning the reality of atoms and molecules in the beginning of the twentieth century, in light of Jean Perrin’s theoretical and experimental work on the Brownian movement. The story told has some rather interesting repercussions for the rationality of accepting the reality of explanatory posits. Section 2 presents the key philosophical debate concerning the role and status of explanatory hypotheses c. 1900, focusing on (...) the work of Duhem, Stallo, Ostwald, Poincaré and Boltzmann. Section 3 examines in detail Perrin’s theoretical account of the molecular origins of Brownian motion, reconstructs the structure and explains the strength of Perrin’s argument for the reality of molecules. Section 4 draws three important lessons for the current debate over scientific realism. (shrink)

Despite much excellent work over the years, the vast history of scientific filmmaking is still largely unknown. Historians of science have long been concerned with visual culture, communication and the public sphere on the one hand, and with expertise, knowledge production and experimental practice on the other. Scientists, we know, drew pictures, took photographs and made three-dimensional models. Rather like models, films could not be printed in journals until the digital era, and this limited their usefulness as evidence. But that (...) did not stop researchers from making movies for projection at conferences as well as in lecture halls, museums and other public venues, not to mention for breaking down into individual frames for analysis. Historians of science are more likely to be found in the library, archive or museum than the darkened screening room, and much work is still needed to demonstrate the major effects of cinema on scientific knowledge. Film may have taken as long to change science as other areas of social life, but one can begin to glimpse important ways in which ‘image machines’ were beginning to mediate between backstage experimental work and more public demonstration even around 1900. (shrink)

ArgumentDiscussions of the scientific uses of moving-image technologies have emphasized applications that culminated in static images, such as the chronophotographic decomposition of movement into discrete and measurable instants. The projection of movement, however, was also an important capability of moving-image technologies that scientists employed in a variety of ways. Views through the microscope provide a particularly sustained and prominent instance of the scientific uses of the moving image. The category of “education” subsumes theses various scientific uses, providing a means by (...) which to bridge the cultures of scientific and popular scientific moving images. (shrink)