Was especially light-sensitive, and they used this discovery as the basis for Between 1826-1837, Niépce & Daguerre found that silver iodide In 1815, Planché noted that chemical rays darkened many kinds of metallic Of converting a mixture of hydrogen and chlorine gases into hydrochloric acid. Lussac & Thénard demonstrated that concentrated sunlight was capable Rays focused on their ability to stimulate chemical reactions. Ultraviolet and infrared radiation, respectively. The terms chemical and heat rays remained popular throughout the 19thĬentury, but they were eventually dropped in favor of the more restrictive terms Was adopted to describe these invisible rays along with the adjacent violet-blue Over time, the simpler term "chemical rays" Reactivity and to distinguish them from the "heat rays" at the otherĮnd of the visible spectrum.
He called them "deoxidizing rays" to emphasize their chemical He noticed that invisible rays just beyond the violetĮnd of the spectrum were even more effective at darkening silver chloride-soaked When he directed sunlight through a prism onto the paper, the violetĮnd of the spectrum was more effective than the reddish end. In 1777, Scheeleįound that paper soaked in silver chloride solution darkened when exposed to He noticed that sunlight turned silver nitrate crystals black. In 1614, Sala made a seminal observation. The Discovery of UV Radiation, Its Properties and Relationship to SunlightĪnd its properties was a gradual process that spanned three centuries and involved Upon the type of organism, wavelength region (UVA, UVB, or UVC) and irradiation Theme is that UV radiation has both beneficial and harmful effects depending Group has its own unique narrative relating it to UV radiation. This is followed by a more detailedĭiscussion of the evidence linking sunlight and UV radiation with physiologicalĪnd pathological changes in humans, non-human animals, and microorganisms. In instrumentation and careful experimentation.
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Were unveiled through a series of serendipitous observations coupled with improvements Of UV radiation, its properties, and relationship to sunlight. Setlow (13) Urbach & Forbes (14) Webb (15) Senger (16) Ananthaswamy ThereĪre a number of excellent reviews on UV photobiology written between 1920-2001,Īnd these should be consulted for more in-depth analyses [cf. The author, and any omissions and shortcomings are his responsibility. The selection of these studies was made solely by Due to the extent of the literature, this review covers only the most important government-supported computer database of health-related research. Between 1960-2001, thereĪre 37,466 publications on the subject "ultraviolet radiation" listed Afterġ920, the number of UV-related publications grew rapidly, reaching at leastĢ75 for the years 1920-27 alone (see Laurens, 1928). (UV) radiation, its properties, and its influences on living organisms. On studies prior to 1920 that were involved in the discovery of ultraviolet This explains the use of the sun in advertisements for erectile dysfunction drugs. With fertility, people worshiped the sun also in the hope of offspring.
In mythology, sunlight was often associated As this review documents, indeed they are. This realization inspired additional studies aimed atĭetermining whether different wavelengths might be responsible for the differentĮffects of sunlight.
Of these principles led to the realization that sunlight is not a single stimulusīut, rather, a collection of stimuli of different wavelengths (e.g., infrared, By the start of the 19th century, the application Power of their ancestors' explanations, sought new mythologies in their searchįor a better understanding of the cosmos and their relationship with it.Ĭentury, a new mythology arose in Europe that was based upon scientific principlesĪnd provided the basis for a more reliable understanding of the relationshipīetween humans and sunlight. Offspring, dissatisfied with the intellectual Of how sunlight provides these life-sustaining influences was immersed Chicago Ave., Chicago, IL 60611-3008, civilizations understood that sunlight provides visibility, warmth, health and vitality. Northwestern University, Feinberg School of Medicineģ03 E.