It's the birthday of Douglas Hartree, who was born in 1897 in Cambridge, England. During World War I, which interrupted his education, Hartree worked on the mathematics of anti-aircraft ballistics. When he resumed his studies at Cambridge, he became interested in the possibility of applying numerical methods to quantum mechanics and developed a method for calculating an atom's distribution of electrons. In 1933 Hartree took up a professorship at Manchester University, where he built a differential analyzer from Meccano, a construction toy (sold as Erector Set in the US). He used the analyzer to calculate railway timetables and, during World War II, solve various numerical problems. Hartree quickly grasped the potential of electronic computation. Commenting on Alan Turing's Automatic Computing Engine in 1946, he said: "The implications of the machine are so vast that we cannot conceive how they will affect our civilisation. Here you have something which is making one field of human activity 1000 times faster. In the field of transportation, the equivalent to ACE would be the ability to travel from London to Cambridge in five seconds as a regular thing. It is almost unimaginable."
