Automatic Blaine Air Permeability Apparatus performs the test for determining the fineness of cements, limes and similar powders expressed in terms of their specific surface according to the above testing standards. The fineness of cement can be automatically measured as specific surface by observing the time taken for a fixed quantity of air to flow through a compacted cement bed of specified dimensions and porosity. The method is comparative rather than absolute and therefore a reference sample of known specific surface is required for calibration of the apparatus.