50 Years Ago

The first practical research tool based on solid state lasers to be made available in the United Kingdom is announced by Kollsman Instrument, Ltd. The 'Pisto Laser', so called because of its double pistol-grip triggering, was designed and developed by the Company's associate in the United States of America, the Kollsman Instrument Corporation. It emits a beam of intense, coherent red light of wavelength 6929 Å., with a beam divergence of less than 0.3 degree ... The radiation output of the pulsed, ruby, laser beam is more than 109 times the corresponding output of the Sun within the same frequency band ... In communications research the 'Pisto Laser' can be used to study the characteristics of very narrow beam-width transmission of optical data; in medical research, high-intensity cauterization; in crystallography, crystal structures using non-linear light transmission; in photography, pictures of extreme clarity; and in biology, biological responses to high-intensity monochromatic stimulation.

From Nature 11 August 1962

100 Years Ago

A good deal has been recently heard about “holes in the air” in connection with sudden collapses of flying machines. Prof. W. J. Humphreys, of the Washington Weather Bureau, writing in The Popular Science Monthly for July, classifies the eight different types of atmospheric disturbance as follows:— A vertical group, including aërial fountains, aërial cataracts, aërial cascades, and aërial breakers, and a horizontal group, including wind layers, wind billows, and aërial torrents; in addition wind eddies fall under both groups. Holes in the sense of vacuous regions do not exist.

From Nature 8 August 1912