Last year, Caltech rededicated a building on its campus following a major renovation. The Alfred P. Sloan Laboratory for Mathematics and Physics became the Ronald and Maxine Linde Hall of Mathematics and Physics. Linde Hall occupies a structure which is now 97 years old and has evolved over that time with the disciplines of physics, mathematics, and electrical engineering.
The building, constructed in 1923, originally had a few names, including Edison High Tension Laboratory, High Voltage Research Laboratory, and High Potential Research Laboratory, but was generally referred to as High Volts. It was the fifth permanent building constructed on Caltech’s campus, after Throop Hall, Gates Laboratory of Chemistry, Culbertson Auditorium, and the Norman Bridge Laboratory of Physics.
Astrophysicist George Ellery Hale, as a Caltech trustee, conceived of the laboratory as part of a strategy of persuading experimentalist Robert Millikan to come to Caltech. Millikan was tortured—his word, not mine—by his decision of whether to come to Caltech or stay at the University of Chicago. Hale’s fellow trustees Henry M. Robinson and Arthur Fleming—both of whom became namesakes of buildings on campus—were also on the board of directors of the local electric company, Southern California Edison.
Hale proposed to them that if the Edison Company bought Caltech a new laboratory, both parties would benefit: “I believe the Company would get its money back in the form of new information regarding insulation and other problems connected with high voltage lines, not to speak of the advertising value.” He was right: The company’s interest came from a decision they made around 1920 to change their transmission lines from 150,000 to 220,000 volts. Such lines and associated insulators, transformers, circuit breakers, and other equipment would need to be able to withstand a massive surge if they were struck by lightning, so the Edison Company wanted to conduct research at a million volts, a higher voltage than could be reliably produced by any existing American laboratory. The lab cost $139,915, of which Edison paid $105,000.
The design of High Volts was also a collaboration. Millikan provided specifications, including a requirement that the building have ventilation to allow ozone to escape but also not let in light. The interior was dominated by a single large industrial space packed with high-voltage apparatus, including two key pieces of million-volt equipment. A million-volt surge generator produced rapid impulses of artificial lightning. In addition, Royal Sorensen, who founded electrical engineering at Caltech when he was hired in 1910, invented the cascade transformer in 1922 (an innovation which was simultaneously made by others in Germany) and designed a million-volt model, composed of four 250,000 volt transformers built by Westinghouse which each weighed 22 tons, for High Volts; it stepped an externally-supplied 15,000 volts up to a million volts of continuous current. Edison engineers designed a steel frame, the second constructed in Pasadena, and prominent architect Bertram Goodhue designed the exterior, which used a diamond pattern to provide texture in the absence of windows. The similarly prominent architectural sculptor Lee Lawrie produced a relief over the entry which conveyed the high voltage research performed within.
Sorensen regularly gave a public lecture and demonstration on high voltage electricity, with the latter portion taking place in High Volts. “It proved to have its usual strong draw this year when, on a rainy Friday evening, almost 1000 people stormed East Bridge,” reported Engineering and Science, Caltech’s research magazine, in 1949. “Prof. Sorensen obligingly gave his lecture twice, and the lab ran off three demonstrations, while a special police detail coped with the crush.”
In his oral history, Caltech chemistry professor John Roberts recalls visiting Caltech as a teenager for these demonstrations:
The High Voltage Lab was a fabulous attraction. What is now the Sloan building then had no windows in it. It was deep down inside—just a great big basement-like room with no upper floors. And they had these big girders up at the top. The floor of this room was filled with all kinds of electrical equipment—enormous transformers, and condensers, and so on, big swooping insulators. It looked like Frankenstein’s laboratory. Great transformers topped with big mushroom rings, you know, they used to shoot sparks off of.… They’d have a “horn gap,” where a pair of wires would be close together at the top of the transformer and far apart at the top of the room. They would start an arc at the bottom and it would grow in length and rise to the ceiling. That was really impressive to watch as the arcs got up to the ceiling, and then crack, and disappear. They’d make this crackling noise as they’d go up. And then they’d charge up the condensers and shoot off big sparks, and blow up some blocks of wood, and stuff like that.
According to the February 1949 issue of Engineering and Science, “these facilities have been used to aid Southern California Edison in the development of high voltage transmission lines, to furnish lightning protection of oil storage tanks for the oil industry, to test insulators for numerous utility companies.” The transmission lines tested at High Volts made it possible to transmit electricity to Southern California from the Hoover Dam in Nevada. Among the significant inventions of the lab was a vacuum switch designed by Sorensen and Millikan which was manufactured for aircraft and other industries.
Going back to 1921, though, as Hale saw it in his letter to his fellow trustees, though, High Volts would have an entirely different benefit for the physicist he was trying to recruit. “Millikan,” he wrote, “would also have the advantage of using enormous voltage to bust up some of his atoms. This possibility, which no other laboratory could match, is what excites him.… When a man gets on the trail of the philosopher’s stone, even if he isn’t after gold, you can accomplish a great deal by offering it to him!”
Millikan’s interest did indeed come from his interest in taking apart atoms and discovering what they were made of. He was also seeking, as Hale’s reference to the philosopher’s stone suggests, to transmute matter from one element to another by reconstructing the nucleus. In 1904, Millikan had already written that “the dreams of the ancient alchemists are true, for the radioactive elements all appear to be slowly but spontaneously transmuting themselves into other elements.” In 1912, he believed he and his student George Winchester produced hydrogen ions from aluminum using high-voltage electricity. In 1919, Ernest Rutherford persuaded more physicists that he had caused nitrogen atoms to eject protons by bombarding them with alpha particles. Several scientists claimed they had turned various metals into gold in the 1920s using electricity—it was a renaissance of alchemy.
Although Millikan submitted a grant proposal for support for this research in 1921, and although he, Hale, and Caltech as an institution occasionally referred to the High Voltage Laboratory as intended for investigations inside the atom, Millikan never published the results of his efforts to transmute matter at Caltech, nor can evidence of it be found in his surviving laboratory notebooks. In his article on the subject, historian Robert Kargon, suggests that “these efforts may have in fact been made but were unsuccessful,” adding that Millikan “preferred to bury quietly unfruitful enterprises; he position as fundraiser for an exciting new research center made such unpublicized interment a practical necessity.” Ultimately, then, the new lab would find other uses.
Charles Lauritsen, who received his PhD from Caltech in 1929 and remained here for the rest of his career, made High Volts a key site for high-voltage X-ray research, building the first million-volt X-ray tube there in about 1930. Lauritsen soon became interested in the medical applications of this device, writing in his patent application that “radiations substantially the frequency of the gamma radiation from radium may be obtained from the tube” and that “such tubes can therefore be employed as the full equivalent of radium in the treatment of disease, or for therapeutic purposes.”
Although Caltech biologists steered clear of medical applications at this time, its physicists did not. Millikan enlisted local physician Seeley G. Mudd, whose mother was already donating a geology building to the Institute in memory of his father, mining tycoon Seeley W. Mudd. That building is now typically called North Mudd, as the younger Mudd later donated an associated building named after himself as well, South Mudd. I for one didn’t realize until I was preparing this talk that the two buildings are named after two different men.
To return to our story, Millikan enlisted the younger Mudd in a partnership researching the therapeutic effects of Lauritsen’s million-volt x-ray tube compared to lower voltage radiation already available in hospitals, and the Los Angeles County General Hospital began to bring cancer patients to High Volts for radiation therapy. Although he was independently wealthy and didn’t receive a salary, and indeed donated money as well as his time to the project, Caltech appointed Mudd became Research Associate in Radiation, and later, in 1935, Professor of X-Ray Therapy. Physician Clyde Emery was made Assistant Professor of X-Ray Therapy at the same time. Caltech’s medical physics research was so active that it became one of the main reasons for the Institute to construct a new building, Kellogg Radiation Laboratory, in 1932.
Meanwhile, Lauritsen’s students, funded by their work maintaining x-ray tubes for radiation therapy, began modifying High Volts equipment for nuclear physics, making Millikan’s vision of deconstructing the atom there a reality; H. Richard Crane, for example, produced neutrons by ion beam for the first time in the early 1930s. “The transmutation of the elements, now an accomplished fact,” wrote Millikan to their funder, W. K. Kellogg, “plus artificial radioactivity, plus neutron beams—all three effects producible by Lauritsen tubes—plus the manifold uses of ultra-short wireless waves, therapeutic and otherwise, open up endless opportunities.”
As with many research programs, radiation therapy came to an end at Caltech when funders—not only Kellogg but also the National Academy of Sciences’ National Cancer Advisory Council and the Childs Foundation, decided to stop funding it. In the early 1940s, Kellogg was dramatically repurposed for research on rocketry as the US prepared to enter World War II.
High Volts retained its unusual, single-room architecture until 1960, when Caltech renovated it into the Alfred P. Sloan Laboratory of Mathematics and Physics, producing a more conventional internal structure, with windows and five floors of space, including new basements, rather than a single large room. By this point, it had had a storied career contributing to electrical engineering, nuclear physics, radiation therapy, spectacular public demonstrations, and even science we might call alchemy.