In 1868 , Ångström created a chart of the spectrum of solar radiation that expressed the wavelengths of electromagnetic radiation in the electromagnetic spectrum in multiples of one ten-millionth of a millimetre ( or . )
In 1868 , Ångström created a spectrum chart of solar radiation that expresses the wavelength of electromagnetic radiation in the electromagnetic spectrum in multiples of one ten-millionth of a millimetre , or 1 × 10 − 10 metres .