Slide-Rule Boys

No branch of the U.S. Army has a better combat record in World War II than the field artillery. It was good in World War I -when more than half all casualties (70% of American) were from artillery fire. In World War II it uses new, time-fire shells far more accurate than shrapnel and six times as destructive against personnel as regular shells which explode on the ground. It masses fire at speeds inconceivable 25 years ago. In seconds it can destroy targets that once took minutes, sometimes hours.

Largely responsible for such speed and accuracy is a logarithmic slide rule, invented in two hours by a captain from the National Guard who switched from the cavalry because he hated horses.

Slow Torture. Now a lieutenant colonel, Abbott Harrington Burns was only a month away from a construction clerk's job with an Arizona telephone company when he was assigned to a Fire Direction Center team at Fort Sill, Okla., in mid-November 1940. In self-defense against slow torture from intricate mathematics, Harry Burns one night experimented with a homemade paper slide rule. Most officers were unimpressed. But one major, George V. Keyser (now a brigadier commanding the 74th Field Artillery in Mississippi), saw the potentialities of Burns's Graphical Firing Table.

Together Burns and Keyser smoothed the G.F.T.'s kinks and adapted it to compute ranges for any powder charge and any weapon. Getting it accepted by the Army was slower work. Eventually Harry Burns was ready to give up; above his desk he pinned a bunch of red tape (to make himself feel at home) and slouched back to ruminate on horses. But Keyser kept rushing in where colonels feared to tread. Eventually he sold the War Department.

Sill's Field Artillery School had not waited for Washington formalities. Experiments had proved that enlisted men, with grocery-store arithmetic and Harry Burns's G.F.T., could do computing that had demanded trained officers, complicated mathematics and 76 pages of firing tables in fine type. And they could do it more than 20 times as fast and far more accurately. With new Fire Direction Center techniques, G.F.T. tied together other artillery developments to deliver fire with wicked intensity and speed.

Quick Murder. Most spectacular development is time fire. By 1941, with 105s replacing 75s, field artillery had abandoned shrapnel for a more effective, more easily controlled shell which could be regulated to explode directly above its target. Bursting at a height of 15 yards, a 105 time-fire shell sprays an area 40 yards wide and five yards deep with razor-sharp, saw-toothed shell fragments. No gun is completely accurate, but with massed time fire blanketing huge areas pinpoint accuracy is no longer a problem.

Massed artillery fire was old in World War I (Napoleon used it first), but standards set at Sill are incredible to oldtime two-percenters.* Twenty-five seconds after the target is pointed out, shells from a dozen 105s are on their way--an hour would be comparable 25 years ago. In routine exercises more than 100 guns obliterate targets 800 yards square less than five minutes after they are assigned--incredible by the standards at Soissons or Saint-Mihiel. Some of this speed-up comes from having changed the firing unit from the battery of four guns to the battalion of twelve. Some comes from lightweight radio and improved field telephone. But most comes from the G.F.T.

Among the first to preach artillery's new possibilities was quiet, pipe-smoking Brigadier General Jesmond Dene Balmer, now Field Artillery School Commandant. Seven months in wartime Washington had taught him that orders are not only to be obeyed but anticipated. Long before the War Department fully realized what time fire could do, Jess Balmer was calling for its use on a huge scale. North Africa proved his point--and led ground forces to multiply orders for time shells. Long before the War Department had recognized the G.F.T., Sill was turning out homemade ones, paper strips mounted on beaverboard. Young officers took them to Guadalcanal and Tunisia, Attu and Sicily. Last month Balmer's command won official commendation from Lieut. General Lesley J. McNair, head of Army Ground Forces: "Battle results . . . have demonstrated conclusively that the current artillery doctrines are sound and probably the most advanced in the world. . . . [This] is due . . . almost wholly to a single factor: the Field Artillery School."

* In France, artillery fire went down 200 yards ahead of troops, who crept within 100 yards waiting for it to lift before attacking. Occasional shorts were inevitable, and infantry learned to expect 2% casualties from its own supporting artillery. Foot soldiers' traditional greeting to artillerymen was two raised fingers, like Winston Churchill's "V" signal.

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