My scientific career has been helped along by two marvelous instances of good luck.
The first occurred while I was a research student in chemistry at Leeds University where my supervisor was Prof. R. Whytlaw-Gray, the leader of a distinguished school for the measurement of atomic weights. His method depended on the use of a very delicate microbalance to determine the vapor densities of substances in their dilute gaseous states.
The problem he gave me was to obtain a new and more precise value of the atomic weight of fluorine by measuring the vapor density of sulfur hexafluoride, a substance well-known for its inertness that is prepared by passing fluorine over powdered sulfur.
After getting my fluorine-generating cell to work properly I made liter upon liter of SF6, which I stored in evacuated flasks. The subsequent purification of the gas was carried out in a vacuum apparatus and consisted, in...