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),
Layer by Layer starts by making a cross on one face with the edge pieces, then putting the corners into position between the edges. By then the layer should be solved. Third, the four edge pieces of the middle layer are solved. At this point the first two layers are solved. Fourth, a cross of the opposite color is made on the last layer. Fifth, the last layer edges are permutated (swapped around). Sixth, the last layer corners are permutated. Finally, the last layer corners are oriented. Most Layer by Layer beginners' methods solve the first two layers using the same technique. However,