> Einstein and Szilard eliminated the risk of leakage by jettisoning the mechanical pump

Einstein–Szilard refrigerator: https://en.wikipedia.org/wiki/Einstein_refrigerator :

> The three working fluids in this design are water, ammonia, and butane. [1] The Einstein refrigerator (co-invented with Leó Szilárd) was actually a modification of an earlier three-fluid absorption design created by Swedish engineers Baltzar von Platen and Carl Munters