Destiny of the Republic - Candice Millard [83]
Four years earlier, while struggling to fend off interference from nearby telegraph wires, which were cluttering his telephone lines with their rapid clicking sounds, Bell had found an ingenious solution. The problem stemmed from the telegraph wires’ constantly changing magnetic field, which created, or induced, corresponding currents in the telephone wires. Bell realized that if he split the telephone wire in two and placed one wire on each side of the telegraph line, the currents would cancel each other out. “The currents induced in one of the telephone conductors,” he would later explain, “were exactly equal and opposite to those induced in the other.” The technique, known as balancing the induction, left the line silent.
The idea had worked, and Bell had patented it in England that same year but had given it little thought since. Now, as he considered the president’s wound, he recalled that his tests in 1877 had shown him that his method of balancing induction could not only achieve a quiet line, it could detect metal. “When a position of silence was established,” he wrote, “a piece of metal brought within the field of induction caused the telephone to sound.”
After “brooding over the problem,” Bell realized that he could turn his system for reducing interference into an instrument for finding metal—the induction balance. He would loop two wires into coils, connecting one coil to a telephone receiver and the other to a battery and a circuit interrupter, thus providing the changing current necessary for induction. Then he would arrange the coils so that they overlapped each other just the right amount. He would know he had them perfectly adjusted when the buzzing sound in the receiver disappeared. If he then passed the coils over Garfield’s body, the metal bullet would upset the balance, and Bell would literally be able to hear it through the receiver. In this manner, the telephone, his most famous and frustrating invention, would “announce the presence of the bullet.”
Bell’s instincts told him that the induction balance would work, but he could not be certain until he tested it. Feeling frustrated and helpless in Boston, without his laboratory, his equipment, or his assistant, he once again turned to Charles Williams’s electrical shop, where he had met both Watson and Tainter, and where, just seven years earlier, he had built the first telephone. At “great personal inconvenience,” Williams did everything he could to help Bell, giving him laboratory space, equipment, and his best men.
Bell, however, still wanted his own man. Tainter, who had continued to work in the Volta Laboratory since the shooting, “received an urgent request from A. G. Bell … to join him.” The next day, he was on a train bound for Boston. Both men knew that, if they were to have any hope of helping the president, they had to work quickly. Although still little more than an idea in Bell’s mind, their invention would be Garfield’s only hope of avoiding death at his doctor’s hands.
• CHAPTER 15 •
BLOOD-GUILTY
We should do nothing for revenge.… Nothing for the past.
JAMES A. GARFIELD
From his cell deep in the District Jail, Guiteau was gratified to learn that, as he had predicted, General William Tecumseh Sherman had sent out his troops. The heavily armed company of artillery that flanked the somber stone building, however, was there not to free the president’s would-be assassin, but to make sure he wasn’t dragged outside and lynched. So great was the fear that a mob would overwhelm the prison that its guards had at first denied that Guiteau was even there. “Information had reached them,” the New York Times reported, “that, should the fact be made known that he was there, the building would be attacked.”
After the initial shock of the president’s shooting, the prevailing feeling throughout the country was one of unfettered rage. The fact that Guiteau had been captured and was in jail, awaiting trial, did little to satisfy most Americans’ desire for immediate revenge. “There were many who felt intensely dissatisfied that