Science: 7,000,000 Volts

After sundown one day last week an airplane slipped in to a landing at "Round Hill," the South Dartmouth, Mass, estate of Hetty Green's stamp-collecting, air-minded son, Colonel Edward Howland Robinson Green. It taxied up close to a capacious airship dock, and out of it stepped President Karl Taylor Compton and Vice President Vannevar Bush of Massachusetts Institute of Technology.

The two men strode into the cavernous metal hangar in which was no dirigible but M. I. T.'s giant electrostatic generator (TIME, March 7, 1932). There they joined newsmen and M. I. T. engineers and miscellaneous scientists. In the gloom loomed the generator— two gleaming 15-ft. hollow aluminum balls, each atop a 25-ft. column of textolite, each column mounted on a massive four-wheel truck. The two trucks were on a single track which ran the length of the hangar and beyond. Small manholes opened into both aluminum balls which were rigged up inside as compact laboratories.

After a quick inspection Dr. Compton boomed: "Perhaps not all of you understand that this is the first test of the Van de Graaff electrostatic generator as a complete machine. . . . Up to the time Dr. Van de Graaff built his small laboratory model [at Princeton] which developed more than 1,000,000 volts [TIME, Nov. 16, 1931], the highest direct current ever attained by man was about 800,000 volts. With this big generator we hope tonight to reach several million volts. ..."

Dr. Compton turned to a dark, heavy-chinned young man standing quietly at his side. Robert J. Van de Graaff was born in Alabama 32 years ago, won a Rhodes scholarship, became a National Research Fellow at Princeton, designed and built his big generator as an M. I. T. research associate.

"Are you ready to start, Dr. Van de Graaff?" "I believe everything is ready, Dr. Compton."

A Van de Graaff staff member clambered up a ladder into the ball which was to serve as the positive terminal. Into the negative ball climbed another, followed by a spunky newshawk. Two more staff men went to shielded control boards at the foot of each column. Builder Van de Graaff barked instructions.

"Remove the ladders! . . . All ready in the spheres? Lights out! Power on!"

A rising hum filled the still darkness of the hangar. Small motors were driving endless paper belts which, riding on pulleys and whizzing invisibly up & down within the columns, picked up electrical charges from the exciters below and piled them up on the balls above. One belt carried negative electricity, the other positive. In the galvanized atmosphere the hair of the watchers stood straight up, their elbows tingled, their fingertips glowed. Luminous halos began to fringe the balls.

Abruptly a thunderclap resounded as a blinding arc leaped from ball to ball. Other flashes followed in a steady crackling punctuated by deafening reports. The air was pungent with ozone. Through the din Dr. Van de Graaff bellowed:

"Widen the gap!"