Forever restless, and untethered by concerns of practicality and marketability, Tesla's mind spawned a vast miscellany of odd inventions. Many of these were never developed beyond the concept stage, and the ideas seemed to grow markedly weirder in the final years of Tesla's life. Invention was normally a deliberate process for Tesla, his every intention and goal fully formed before he and his crew lifted a finger. But there were times when he stumbled upon a new discovery by mistake. Tesla performed his first experiments with resonance technology at his New York laboratory by firing up a small oscillator, which caused a minor amount of vibration. Suddenly, an alarmed squad of police officers stormed into the lab, demanding that Tesla stop at once. Manhattan was shaking for miles around. Tesla had not taken into account how resonance waves grow stronger the further they travel from their source. He had unintentionally created what became known as Tesla's earthquake machine. Tesla also applied his resonance engines in bizarre forms of physical therapy. He created machines that flooded the human body with electrical currents and strong vibrations, intended to soothe aches and promote healing. And Tesla wasn't just the inventor of the "electrotherapeutic" device -- he was also a client. He reportedly became somewhat addicted to administering the treatment to himself, insisting that a session with the machine rejuvenated him on his long stretches of work without food or sleep. Tesla once let his friend Samuel Clemens try out the healing machine. The author is said to have enjoyed the experience tremendously -- until the vibrations brought him a case of spontaneous diarrhea. Tesla marketed this invention, and the Tesla Electrotherapeutic Company was one of the few commercial enterprises of his old age that was marginally successful. Tesla gained another accidental revelation during his testing of the magnifying transformer in Colorado Springs. One evening during the construction of the device, the apparatus began to sound out a series of precise clicks, similar to Morse code. Tesla was convinced that these were signals being sent by extraterrestrial life. Tesla had expressed his belief in life on Mars, and now he thought he had proof. He later conceived of transmitters for communicating with Martians, espousing his view that the establishment of peaceful relations with our neighbors from outer space was among the most pressing duties that lay before humanity. In his later years, Tesla was fascinated with the idea of light as both a particle and a wave -- the fundamental proposition of what would become quantum physics. This field of inquiry led to the development of his death ray. Tesla also had the idea of creating a "wall of light" by manipulating electromagnetic waves in a certain pattern. This mysterious wall of light would enable time, space, gravity and matter to be altered at will, and engendered an array of Tesla proposals that seem to leap straight out of science fiction, including anti-gravity airships, teleportation and time travel. The single weirdest invention Tesla ever proposed was probably the "thought photography" machine. He reasoned that a thought formed in the mind created a corresponding image in the retina, and the electrical data of this neural transmission could be read and recorded in a machine. The stored information could then be processed through an artificial optic nerve and played back as visual patterns on a viewscreen. It's a pity Tesla never made this last invention a reality. With the dearth of written notes and documentation he left behind for modern science to study, we can only conclude that Tesla's weirdest ideas were misconceived fantasies -- maybe even symptoms of madness. Nothing less than a comprehensive recorded catalog of his brain waves could prove otherwise. Next: The exclusion of Tesla from the pages of history and the popular consciousness. Did he earn his obscurity, or was it thrust upon him? Tesla began his college education at Graz Polytechnic Institute, pursuing studies of the topic that fascinated him above all others: electricity. He had done fairly well in grade school, but his lack of facility at freehand drawing kept him from excelling in technical courses. But in college, Tesla was delighted to find, he was permitted to focus exclusively on what he was best at. He studied feverishly almost around the clock, in a routine that began at 3 a.m. and ended at 11 p.m., every day. He aimed to impress his parents with his scholarly achievements, in part because his father had been reluctant to send him to the university, wishing Nikola would follow in his footsteps in the clergy. He also entertained fantasies of going to America and teaming up with the reigning leader of electrical invention, Thomas Edison, so that their combined forces might revolutionize the world. Tesla was an extraordinary student who frequently enraged his professors, questioning the technological status quo with an insight that surpassed his instructors'. He rebelled most stringently against the acceptance of direct current as the sole means of delivering electrical power. It was plain to him that DC was inefficient and incapable of adequately transmitting power over long distances, and there had to be a better way. There was talk of a theoretical "alternating current" system, but no one had figured out how to make it work. AC was frowned upon as a fanciful dream by the scientific establishment, in much the same way as cold fusion is regarded today. Tesla's merest suggestion of AC brought scorn in his lecture halls, but he was never discouraged enough to abandon the enticing riddle. In the middle of Tesla's sophomore year of college, his father was felled by a stroke. Nikola returned home, and his father died soon after. Tesla never returned to the Polytechnic Institute. Lacking funds for tuition, he took a job at a government telegraph office. Tesla despaired for his interrupted education, but held on to his dream of becoming an electrical pioneer. It was at this time that Tesla endured his ordeal with hypersensitivity that reduced him to a bedridden invalid. Considering the depressing turns his life had just taken, the bizarre affliction could possibly have been psychosomatic in origin. Whatever its cause, when Tesla finally emerged from the prolonged fugue state, he was armed with a powerful new insight on how alternating current could be successfully attained. His great mental leap was this: two coils positioned at right angles and supplied with alternating current 90 out of phase could make a magnetic field rotate, with no need for the cumbersome commutator used in direct current motors. Tesla knew it would work without even having to build it and test it. Constructing it mentally and letting it run in his mind was proof enough for him. This was Tesla's method for developing inventions throughout his career: no journals, no blueprints, no prototypes. The propensity for turning ideas into concrete visualizations which had tormented him in his youth was now turned to Tesla's advantage. He believed his technique was not only a valid one, but actually superior to the common practice of getting everything down on paper and conducting tentative trials. "The moment one constructs a device to carry into practice a crude idea, he finds himself unavoidably engrossed with the details of the apparatus," Tesla wrote in his autobiography. "As he goes on improving and reconstructing, his force of concentration diminishes and he loses sight of the great underlying principle." Tesla now possessed the answer, but the problem of putting it into practice remained. In 1882 he found employment with Continental Edison Company in Paris, distinguishing himself as a fine engineer. Two years later he traveled to New York to meet the company's president, Thomas Edison himself. It was not the harmonious meeting of the minds Tesla had once dreamed of. Edison regarded the hotshot European with contempt, and assuredly held no intentions of collaborating with him on some harebrained AC scheme. Edison viewed AC as a pipe dream at best, or, at worst, a threat to usurp his DC-based empire. Tesla tried to make the best of the situation by offering to improve Edison's existing technology to the highest level possible. He promised to increase the efficiency of the DC dynamos by 25%, within two months' time. The skeptical Edison said he would pay Tesla fifty thousand dollars if he succeeded. Exerting a massive, virtually non-stop effort, Tesla accomplished the feat, enhancing the dynamos by an even better margin than he proposed. But when he asked for his fifty thousand dollars, Edison refused to honor the deal, claiming that he had only been joking. Infuriated, Tesla quit and never worked for Edison again. Tesla was soon approached by a group of investors who wished to market the arc lamp he had developed. Thus was the Tesla Electric Company founded. Tesla was eager to seize this opportunity to bring AC into existence at last, but his investors wanted nothing to do with it -- so Tesla found himself rejected by the company that bore his own name. That company soon ran afoul of financial hardships, leaving Tesla's stock shares worthless and stripping him of his rights to the arc light. Penniless, his enterprising spirit finally broken, one of the world's most brilliant men was reduced to shoveling in a labor crew for a dollar a day. He planned on committing suicide on his upcoming thirtieth birthday, at the stroke of midnight. Before that could happen, A. K. Brown of Western Union learned of Tesla's plight. Aghast, Brown was determined to restore the genius to a worthy place, and offered to furnish him with a laboratory of his own. And what's more, Brown wanted Tesla to pursue the possibilities of alternating current. Granted a blessed salvation, Tesla immediately went to work assembling his AC dynamo at last. It functioned in reality precisely as it had all those years inside his head. Tesla demonstrated his invention in a heavily publicized lecture, and instantly became the toast of the engineering community. Among the AC converts in the lecture's audience was George Westinghouse, who negotiated with Tesla to manufacture the dynamos. The first application of the new technology: Niagara Falls. Westinghouse won the coveted contract to harness Niagara, bidding half of what Edison bid for the installation of a DC system. In 1895, the Niagara AC power system enjoyed a flawless inauguration, transmitting electricity to Buffalo twenty-two miles away -- a complete impossibility in the suddenly outmoded world of direct current. No longer a curious luxury reserved for the urban upper class, electric power in the home would now be commonplace. For the first time in his life, Nikola Tesla was an indisputable success.