Fig. 2. Stray field (STRAFI) profiles of two sandstone blocks into which molten paraffin wax and mineral oil have diffused from their right faces. Markers were placed in contact with the left faces. (a) Intensity distributions recorded from points at the peak of the first, second, and third echoes of the echo train. (b) Amplitude of the echoes along the echo train for paraffin and mineral oil. Points plotted are the averages over six adjacent slices at positions indicated in the profile by short bars.