The Author presents the results of six years of observation on two control sets of buildings constructed on expansive clays. These data provide very important field observations of movements which have actually taken place and they form the basis for correlation with laboratory theories and hypotheses. As an example of such application the information given by the Author in Table I has been reduced to inches of heave per foot of depth over the depths covered by the depth points in the thermal house. These data are plotted on Fig. 1 which is the same as Fig. 8 of the writer's joint paper. This shows very good agreement between observed heave at depth and predictions of this same quantity from the double oedometer test.