Flashback

75 years ago
Joyce Jacobson Kaufman born in the US. Most notably she described a new theoretical method to code and retrieve carcinogenic hydrocarbons. She was awarded the American Chemical Society’s Garvan Medal in 1974, and the Martin Company Gold Medal for Outstanding Scientific Accomplishments three years running.

100 years ago
Harriet Brooks’s paper A Volatile Product from Radium published in Nature. Rutherford described Brooks as the most outstanding woman in the field of radioactivity, after Marie Curie. He credited her identification of radon as vital for his theory of the transmutation of elements. Her career was cut short due to the establishment view that women could not marry and continue in a scientific career.

165 years ago
Hippolyte Bayard held the first photographic exhibition with a display of 30 photographs in France. However, his ill-advised delay in publishing details of his work meant he is not generally recognised as the inventor of photography.

180 years ago
William Thomson, later Baron Kelvin of Largs, born in Ireland. His thermodynamic studies led Thomson to propose, in 1848, what we now know as the Kelvin absolute temperature scale.

205 years ago
The first steps to developing the International System of Units were taken with the deposition of platinum standards for the metre and the kilogram in the Archives de la R?publique, Paris.