The Age of Radiance Read Online Free

the vacuum tube that glowed, immediately began experimenting with fluorescent materials and their emissions.
    Henri’s grandfather, Antoine César Becquerel, was a Parisian celebrity for having discovered the use of electrolytes to refine metal and was one of the first graduates of the École Polytechnique, which became so central to the military, scientific, and engineering cultures of France that anyone wanting a career in those fields needed to be a polytechnicien . After Antoine César was told in 1815 that he was terminally ill and that death would arrive shortly, he resigned from the army, became a physics professor at Paris’s Musée d’Histoire Naturelle, developed a keen interest in electricity, electrochemistry, and fluorescence, became the museum’s director, and lived to the age of ninety. After himself graduating from the Polytechnique, son Alexandre-Edmond worked at his father’s museum and taught at his father’s school. The Becquerels would assemble at their institution a profound collection of minerals that could absorb, and then radiate, light. They were of two kinds: those that could glow after the light was turned off phosphoresced; and those that only glowed with the light on luminesced. Antoine César told his son,“I will never be satisfied with explanations they give why some chemicals and minerals shine in the dark. Fluorescence is a deep mystery and nature will not give up the secret easily.” By 1896 and the age of X-rays, grandson Antoine Henri had the Musée chair and taught at the Polytechnique, following in his father’s and grandfather’s shoes with fluorescence and phosphorescence; he also typified his era by sporting a commandingly luxuriant and astonishingly manicured barrage of facial hair.
    After winning his doctorate investigating crystal phosphorescence, Henri decided to take the Becquerels’ dynastic expertise into a new direction inspired by Röntgen, with this one experiment:“One wraps a Lumière photographic plate with a bromide emulsion [photography then being done on glass panes coated with a warmed colloidal suspension of potassium bromide and silver nitrate] in two sheets of very thick black paper, such that the plate does not become clouded upon being exposed to the sun for a day. One places on the sheet of paper, on the outside, a slab of the phosphorescent substance [Becquerel used uranyl potassium sulfate—a uranium salt], andone exposes the whole to the sun for several hours. When one then develops the photographic plate, one recognizes that the silhouette of the phosphorescent substance appears in black on the negative. If one places between the phosphorescent substance and the paper a piece of money or a metal screen pierced with a cut-out design, one sees the image of these objects appear on the negative. . . . One must conclude from these experiments that the phosphorescent substance in question emits rays which pass through the opaque paper.” If Becquerel had been able to conduct his research with modern photographic paper, he would have been even more flabbergasted, for the results are the shadow of a rock veined in energy; matter seeming to pulse with an inner life.
    Henri was trying to determine if uranium captures sunlight and emits it later. One day was so overcast that he decided it wouldn’t be productive, so he put away that day’s plate and his rocks in a drawer. By accident, he developed that pane as well and was stunned to find that“there is an emission of rays without apparent cause. The sun has been excluded.” Even after leaving his ore in the dark for many months, it still inscribed its uranic form into the photographic gelatin, and no other element he tried matched this feat. When he discovered that uranium’s emanations could penetrate aluminum, copper, and even platinum, he believed he’d discovered another form of Röntgen rays.
    Becquerel’s uranium results were in equal measure mystifying and alarming because all the other