On the extinction‐coefficient: particle size relationship for fine mineral powders

In this work a short account is given of researches into the measurement of the size characteristics of mineral powders by photo‐extinction methods which have led to an experimentally derived curve relating the extinction coefficient for a suspension to the size of particle of the material in suspension, for the size range 0‐50 microns. While it is not claimed that the validity of this curve is rigidly established, it is believed that it is considerably more reliable than any previously suggested and to have an accuracy sufficient for many industrial purposes.