A New Unit in Photo-electric Colorimetry

Abstract

THE quantity E^{1 per cent}_{1 cm.} does not always lend itself to be used in photo-electric colorimetry. As absorption is generally determined where strong bands occur, a 1 per cent solution in a layer of 1 cm. gives in most cases a reading far below the range of sensitivity of the instrument. Furthermore, it will be found that in many cases the Beer–Lambert law cannot be used for extrapolating from E^{1 per cent}_{1 cm.} values those concentrations which cover the useful parts of the scale.