THE consistency of margarine and other commercial fats depends to a large extent on the relative amounts of liquid and solid fats present. The usual method for determining these values is by dilatation measurements and the dilatometer is used fairly considerably for this work. There are, however, certain inherent errors in this type of measurement. It is stated that the calculation of liquid/solid content from dilatometric data is either not possible with any degree of accuracy1 or even that it is impossible2 with complex mixtures of glycerides. This arises from the fact that a prior knowledge of the glycerides present is required and that mathematical adjustment is needed to take account of the differert melting dilatations. Such prior knowledge is not always available.