John Tyndall in the context of "Scattering"

Spontaneous generation is a superseded scientific theory that held that living creatures could arise from non-living matter and that such processes were commonplace and regular. It was hypothesized that certain forms, such as fleas, could arise from inanimate matter such as dust, or that maggots could arise from dead flesh. The doctrine of spontaneous generation was coherently synthesized by the Greek philosopher and naturalist Aristotle, who compiled and expanded the work of earlier natural philosophers and the various ancient explanations for the appearance of organisms. Spontaneous generation was taken as scientific fact for two millennia. Though challenged in the 17th and 18th centuries by the experiments of the Italian biologists Francesco Redi and Lazzaro Spallanzani, it was not discredited until the work of the French chemist Louis Pasteur and the Irish physicist John Tyndall in the mid-19th century.

Among biologists, rejecting spontaneous genesis is no longer controversial. Experiments conducted by Pasteur and others were thought to have refuted the conventional notion of spontaneous generation by the mid-1800s. Since all life appears to have evolved from a single form approximately four billion years ago, attention has instead turned to the origin of life.

The Weisshorn (German, lit. white peak/mountain) is a major peak of Switzerland and the Alps, culminating at 4,505 metres (14,780 feet) above sea level. It is part of the Pennine Alps and is located between the valleys of Anniviers and Zermatt in the canton of Valais. In the latter valley, the Weisshorn is one of the many 4000ers surrounding Zermatt, with Monte Rosa and the Matterhorn.

The Weisshorn was first climbed in 1861 from Randa by the Irish physicist John Tyndall, accompanied by the guides J.J. Bennen and Ulrich Wenger. Nowadays, the Weisshorn Hut is used on the normal route. The Weisshorn is considered by many mountaineers to be the most beautiful mountain in the Alps and Switzerland for its pyramidal shape and pure white slopes.

In physics, scattering is a wide range of physical processes where moving particles or radiation of some form, such as light or sound, are forced to deviate from a straight trajectory by localized non-uniformities (including particles and radiation) in the medium through which they pass. In conventional use, this also includes deviation of reflected radiation from the angle predicted by the law of reflection. Reflections of radiation that undergo scattering are often called diffuse reflections and unscattered reflections are called specular (mirror-like) reflections. Originally, the term was confined to light scattering (going back at least as far as Isaac Newton in the 17th century). As more "ray"-like phenomena were discovered, the idea of scattering was extended to them, so that William Herschel could refer to the scattering of "heat rays" (not then recognized as electromagnetic in nature) in 1800. John Tyndall, a pioneer in light scattering research, noted the connection between light scattering and acoustic scattering in the 1870s. Near the end of the 19th century, the scattering of cathode rays (electron beams) and X-rays was observed and discussed. With the discovery of subatomic particles (e.g. Ernest Rutherford in 1911) and the development of quantum theory in the 20th century, the sense of the term became broader as it was recognized that the same mathematical frameworks used in light scattering could be applied to many other phenomena.

Scattering can refer to the consequences of particle-particle collisions between molecules, atoms, electrons, photons and other particles. Examples include: cosmic ray scattering in the Earth's upper atmosphere; particle collisions inside particle accelerators; electron scattering by gas atoms in fluorescent lamps; and neutron scattering inside nuclear reactors.

The X Club was a dining club of nine men who supported the theories of natural selection and academic liberalism in late 19th-century England. Thomas Henry Huxley was the initiator; he called the first meeting for 3 November 1864. The club met in London once a month—except in July, August and September—from November 1864 until March 1893, and its members are believed to have wielded much influence over scientific thought. The members of the club were George Busk, Edward Frankland, Thomas Archer Hirst, Joseph Dalton Hooker, Thomas Henry Huxley, John Lubbock, Herbert Spencer, William Spottiswoode, and John Tyndall, united by a "devotion to science, pure and free, untrammelled by religious dogmas."

The nine men who would compose the X Club already knew each other well. By the 1860s, friendships had turned the group into a social network, and the men often dined and went on holidays together. After Charles Darwin's On the Origin of Species was published in 1859, the men began working together to aid the cause for naturalism and natural history. They backed the liberal Anglican movement that emerged in the early 1860s, and both privately and publicly supported the leaders of the movement.