Non-destructive chemical analyses have been made of 80 English and Scottish pewter measures. The x-ray fluorescence analysis method used permits the simultaneous qualitative determination of thirteen elements present in pewter within a few minutes. Results of the analyses are given and conclusions drawn regarding the composition of English vs. Scottish measures. Certain objects previously thought to be authentic are shown to have anomalous chemical compositions. Changes in composition with time are discussed, as are variations in composition between measures and other forms of English and Scottish pewter.