Ozone layer radiation was matched to only one known chemical, ozone. Its properties were explored in detail by the British meteorologist G. M. B. Dobson, who developed a simple spectrophotometer (the Dobsonmeter) that could be used to measure stratospheric ozone from the ground. Between 1928 and 1958, Dobson established a worldwide network of ozone monitoring stations, which continue to operate to this day. The "Dobson unit", a convenient measure of the amount of ozone overhead, is named in his honor. The ozone layer absorbs 97 to 99 percent of the Sun's medium-frequency ultraviolet light (from about 200 nm to 315 nm wavelength),
The Layer Quaternity God on High" and "I will exalt thee my God" ". (Latin upper captions translated) Libavius' illustration and the marble sculpture of the Layer Quaternity share an identical pairing including a naked figure (lower pair), a bare-legged royal male and a regal draped female (upper pair) as well as the titled captions "Gloria" and "Labor", along with the symbols of palm branch, "rotundum", and moon. The similarities between the captioned phrases of Libavius' illustration to those of the single-word titles of the Layer Quaternity suggest that in time sequence, the Layer monument was based upon and installed before 1606, the