This investigation into the nature of the clay substance contained in the fireclay from Glenboig was undertaken at the suggestion of Professor J. W. Gregory. Professor Gregory thought that the fine material might be halloysite, and the results obtained tend to confirm this view.

The very finest material was separated by repeated washing from a sample of the best clay, and used for the analyses. Although apparently white when suspended in water, the material when dry had a decided buff colour. As the colour indicated the presence of some impurity, efforts were made by further washing to remove it; but with no good result. The sample was dried in the steam oven and analysed.