Terrors and Marvels: How Science and Technology Changed the Character and Outcome of World War II by Tom Shachtman. William Morrow, $26.95, 360 pages.

The Chapel Hill News

July 28, 2002

When Science Went to War

By Phillip Manning

Two months after declaring war on Japan and Germany in 1941, the United States was losing ships and sailors at horrendous rates. Off Cape Hatteras, a German U-boat sank three steamers in one night. During the next 12 months, German subs sank over 100 merchant vessels along the East Coast. Oil slicks and dead bodies washed up on American beaches. To make matters worse, the United States was unable to sink a single submarine in the first few months of war. German submariners called this the "happy time."

The fate of American merchant ships trying to cross the Atlantic to supply England with food and weapons was even more tragic. By the middle of 1943, the Allies had lost over 7,500 ships and 40,000 seamen to German subs. American ships were sitting ducks, with no way to detect submarines and no way to defend themselves. "If U-boat success continued to climb," wrote one American official, "England could be starved out, the U.S. could mount no overseas attack on the Nazi power." Fortunately, help was on the way.

In his book, "Terrors and Marvels: How Science and Technology Changed the Character and Outcome of World War II" (William Morrow, $26.95), Tom Shachtman tells how British and American scientists developed the radar system that helped win the Battle of the Atlantic. Radar had been around since 1888, when German scientist Heinrich Hertz demonstrated that solid objects reflected radio waves. The military was slow to see the advantages of radar until airplanes - and the need to detect them before they could reach their target - became a crucial part of warfare in the late 1930s.

Anticipating German air raids, Britain was the first nation to extensively employ radar. It established a series of radar stations called the Home Chain. The bombing began in August 1940, but thanks to the Home Chain, the British were ready. A British fighter plane required 13 minutes to scramble and climb to 20,000 feet. Radar gave the RAF 20 minutes notice of an attack. The advance warning made the difference; British pilots shot down so many German planes that Hitler stopped the daylight bombing of England. Churchill memorably commemorated the men of the RAF for saving Britain, but the Home Chain, devised by scientists and operated primarily by women, deserve a great deal of credit, too.

Unfortunately, the radar used in the Home Chain was too bulky to fit into airplanes and to imprecise to locate the conning towers of submarines at sea. A more compact, more powerful system was needed. The answer was microwave radar, which operates at shorter wavelengths, producing a tighter beam that can detect the position of a plane or submarine more precisely. But microwave radar requires short bursts of very high power. And in the 1930s was nobody knew how to make such a power source.
The breakthrough came in 1939 when two British physicists, John Randall and Henry Boot, invented the cavity magnetron, a palm-sized device powerful enough to generate microwaves. British officials were convinced they would need American assistance in manufacturing the magnetrons and other components needed for microwave radar. To get enough microwave radar sets to equip thousands of ships and planes for antisubmarine warfare, a British contingent set out for America. With them, they brought a box containing Britain's most closely guarded secret, the crown jewels of the Empire - six prototype magnetrons.

The British team was led by Sir Henry Tizard. The man he met in Washington was Vannevar Bush, the head of the National Defense Research Committee, an organization established to harness science to the war effort. The purpose of the meeting was to exchange military information. Over dinner at the exclusive Cosmos Club, the British revealed their precious secret. A day later, scientists from both teams met at the estate of Alfred Loomis, a wealthy financier who had quit Wall Street for a career in physics. That meeting, Shachtman writes, "laid the foundations for the American manufacture of the magnetrons."

The battle in the Atlantic began to turn in late 1942 when microwave radar was installed on British ships and planes. But Admiral King, the commander of the American naval forces, refused to install the new radar on American sub hunters. A confrontation between King and Bush cleared the air, and microwave radar soon appeared on Navy ships and planes. As a result, not a single Allied ship was lost to German U-boats between June and October 1943. Although other scientific achievements by the Allies, such as breaking the German radio code and improved depth charges, played a role in the defeat of the U-boats, Admiral Donitz, who was in charge of German submarine warfare, attributed his defeat to the Allies' superior airpower - and microwave radar.

Part 2 of this column will explore the contributions of Alfred Loomis, the tycoon who turned to science and helped win the war.
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