The Curie Method
Marie and Pierre Curie transmitted the known charge of quartz to the electrometer and then compared it with the charge produced by the radioactive sample that they wanted to measure. This piece of ingenuity allowed them to obtain accurate measurements even though the currents involved were very weak (10^-13 amperes).
"[Marie Curie] sits in front of the apparatus, conducting measurements in the semi-darkness of an unheated room to avoid fluctuations in temperature. The series of tasks involved—opening the device, starting the chronometer, lifting the weight, etc.—are performed by Madame Curie with an admirable sense of discipline and harmony. She moves her hands with a precision that not even a piano virtuoso could match. It is a perfect technique, which has the effect of reducing the margin of human error to zero. After her calculations, which Madame Curie completes eagerly in order to compare the results, we see her sincere, unconcealed joy, because the differences are well below the permissible limit, which ensures the accuracy of her measurements."
Catherine Chamié, Marie Curie's colleague