This is the second article investigating the effect of moisture on the adhesional forces acting between individual particles and between individual particles and flat surfaces. A novel technique for directly measuring the adhesional force for an array of individual particles has been developed and is described. The array is composed of several thousand particles placed in the apertures of an electroformed microsieve and ’frozen’ in position within the apertures with an ultraviolet curing adhesive. The adhesional force is measured with an electronic balance by firstly contacting the array and a surface, separating them, and then recording the greatest negative balance reading. As this means that the adhesional force between individual contacts is magnified several thousand times, the technique is robust and because of the regularity of the aperture spacings it is possible to study the adhesion between an array of particles and a matching array. The mean adhesional force of several thousand particle contacts is more representative of the powder structuring potential than taking the value of a single, and possibly atypical, contact point. It has been shown that the adhesional forces are dependent on the properties of the contacting solids, the relative humidity and the rate of separation of the surfaces. Different solid properties were obtained by using particles of different materials, sizes and shapes and by the roughening of the flat contacting surface. The effect of washing and treating the contacting surfaces with surfactants was also examined. The use of a surfactant can alter the mean adhesional force by a factor of up to 30 and humidity changes can alter the force by a factor of up to 20. For spherical particles, it has been found that the adhesional force increases linearly with particle diameter and decreases as the roughness of the flat surface increases. For irregular particles, the forces are usually smaller and they may increase with increasing surface roughness. Results confirm theoretical predictions as far as the absolute value of the adhesional force is concerned and indicate additional surface variables that need to be taken into account in the prediction of critical relative humidities.