Abstract
A double beam spectrophotometer has been developed which uses a logarithmic amplifier to obtain absorption coefficients and the area under absorption curves. The wavelength range is from 3000 Å to 2.3 μ and resolution is determined by the grating monochromator to which the system is attached. With a resolution of 1 Å an absorption coefficient of 0.02 is easily measurable. The optical and electronic system of the instrument and its performance are described.