Measuring the rays from uranium

In April 1898, Marie Curie presented a short communication to the French Academy of Sciences on rays emitted by uranium and thorium compounds. She measured their effect with an electrical method using a piezoelectric quartz apparatus developed with Pierre Curie.

The measurements suggested that the activity was tied to the substances themselves. This work gave Curie a way to compare samples quantitatively and led her to investigate minerals that proved more active than uranium alone.

Historical note: This is a modern summary of the research, not a text written by Curie.