1940

Milestones

• Mount Palomar Observatory construction advances

  A Sentence Interrupted Mid-Clause

  The two-hundred-inch Hale Telescope had been dreamed up in the late 1920s by George Ellery Hale, a man constitutionally incapable of building a small instrument, and its enormous Pyrex mirror — a single disc weighing nearly fifteen tons — had been poured at Corning, New York, after an earlier attempt cracked on cooling, and then spent years under the patient hands of opticians grinding it to a tolerance of millionths of an inch. By 1940 the great tube was taking shape on Palomar Mountain in California, and then the war arrived and scattered the astronomers into radar laboratories and weapons programmes, leaving the half-finished telescope to sit under its dome like a sentence interrupted mid-clause. The mountain itself was briefly darkened at night for fear that Japanese aircraft might use its glow as a navigational marker — a precaution that says something about how seriously both sides took the California coastline. First light would not come until 1948, eight years after Hale himself had died, never seeing the instrument his ambition had conjured. When it finally opened its eye, it doubled the known radius of the observable universe.

  Astronomy/Space

• Chain Home radar proves decisive in the Battle of Britain

  Four Minutes Was Enough to Climb

  Chain Home was, by any technical measure, a rather crude system: it broadcast on long wavelengths that the Germans knew about, its tall wooden masts were visible from the air, and the best Luftwaffe radar of the period was in several respects superior. What Chain Home had was presence — a network of stations stretching along Britain's eastern and southern coasts that had been operational since 1937 — and, crucially, integration with the command-and-control system that Hugh Dowding had built around it, feeding raw reports through a filter room to the operations tables where controllers could direct Fighter Command's outnumbered squadrons with unusual precision. The average warning time of about four minutes was enough, in most cases, to scramble and climb. German planners had understood that the masts were radar installations; what they miscalculated was how decisively the organisational layer around them would multiply the information's value. The RAF was not simply seeing the enemy earlier; it was acting on what it saw in a coordinated way its opponents could not match. Technology and organisation together accomplished what either could not alone — a lesson that has had to be relearned at considerable expense in several subsequent decades.

  PhysicsTechnology

• Early computer development accelerates under wartime pressure

  A Machine That Never Lies to Itself

  The Enigma machine was, from one angle, a beautifully elegant engineering problem: a polyalphabetic cipher whose daily key settings produced an astronomical number of possible configurations, enough that German operators had been assured it was unbreakable in any practical timeframe. Alan Turing and Gordon Welchman at Bletchley Park in Buckinghamshire spent the early months of 1940 thinking carefully about the machine's one structural weakness — that it could never encode a letter as itself — and designed the Bombe, an electromechanical device that exploited this flaw by running through possible settings and eliminating the ones that produced contradictions. The first Bombe came into operation in March 1940, standing about six feet tall and sounding, by all accounts, like a particularly anxious knitting machine. It was not a computer in any modern sense — it could not be programmed, could not store data — but it embodied something genuinely new: the idea that a logical machine could do the eliminative reasoning that would exhaust a human cryptanalyst in days, and do it in minutes. By the war's end, more than two hundred Bombes were running. The machines and almost everything about them were destroyed or classified afterward, which is one reason it took decades for the world to properly credit what had been built.

  Technology

• Penicillin production scaled for wartime use

  Nurses Cycling the Mould Back Through

  Alexander Fleming had noticed in 1928 that a stray mould was killing the bacteria on one of his culture plates, published a paper that attracted modest interest, and then moved on to other things. It was Howard Florey and Ernst Chain at Oxford who returned to the compound a decade later, purified it with serious effort, and in 1940 demonstrated first in mice and then in a cautious handful of human patients that penicillin could arrest infections that would otherwise be fatal. The clinical results were striking enough to silence scepticism; the problem was purely logistical — Penicillium notatum produced the substance in maddening quantities, requiring the processing of enormous volumes of mould broth to extract enough for a single treatment. At one point Oxford nurses were cycling urine from patients back through the purification process to recover whatever penicillin had passed through unchanged. The arithmetic of war — great numbers of soldiers with great numbers of infected wounds — made scaling this trickle into a flood a matter of some urgency, and by 1941 Florey was in the United States persuading pharmaceutical companies to take the problem seriously. That industrial campaign would eventually yield enough penicillin to treat Allied casualties in the 1944 landings. It is a reasonable estimate that the drug has since saved more lives than the war destroyed.

  Medicine