The Man Who Stalked Einstein (12 page)

Within months of Roentgen’s discovery, X-rays found their principal application in
medicine. In Glasgow, Dr. John McIntyre showed the potential of medical imaging to
demonstrate the presence of kidney stones and swallowed foreign objects. His work
was emulated at the Dartmouth Infirmary in the United States by Dr. Edwin Frost, who
showed the advantages of roentgenographic imaging in diagnosing broken bones. The
Roentgen rays found extensive medical applications during the Boer War and in World
War I. Marie Curie famously spent the money she received with her second Nobel Prize
on a mobile X-ray machine that she drove along the front lines, exposing radiographs
to improve the treatment of wounded soldiers.

X-ray frenzy extended beyond medical applications. Before it was recognized that
overlong and repetitive exposure to X-radiation was acutely injurious and, with excessive
exposure, might induce cancer in the long term, entrepreneurs seeking to capitalize
on Roentgen’s discovery employed X-rays in new consumer products and even entertainment.
Pitchmen ballyhooed harmless but ineffectual home remedies containing fluids they
said had been exposed to X-rays as curative for everyday ills like headaches and constipation.
Fears developed that the dissemination of X-ray apparatuses would infringe on personal
privacy. There were rumors that X-rays would allow the unscrupulous to see through
women’s clothing, prompting one company to quite profitably sell a line of X-ray-proof
garments. A bit of doggerel played upon this conceit:

For now-a-days I hear they’ll gaze,

Through cloak and gown and even stays,

Those naughty, naughty Roentgen Rays.

As Roentgen’s popularity grew, Lenard stewed from the sidelines. Lenard eventually
received his Nobel Prize in 1905 for the work he’d done with high-energy vacuum tubes,
but that did not reverse the public perception. The press glorified Roentgen, while
the name “Lenard” hardly bore mention. He had missed the big discovery and received
short shrift. Despite his having done the work that had made possible the discovery
of the X-ray, next to Roentgen, he was comparatively an unknown.

Lenard’s experience with Roentgen presaged his attacks on Einstein by a quarter of
a century. How unfair! It had been his contributions that underlay everything that
Roentgen had described. Roentgen had been lucky; his discovery was simply the logical
next step to the groundwork Lenard had laid. Lenard didn’t fault a giddy and naïve
public. It wasn’t their fault that they were ignorant of the complete story. It was
Roentgen. Why hadn’t Roentgen set the record straight by giving him credit as a full
partner, for being the one who had enabled his observations?

Lenard’s relationship with Roentgen, as with Einstein, began benignly, even with
admiration. In an early letter written by Roentgen to Lenard in 1894, Roentgen expressed
a desire to acquire some of the aluminum windows that Lenard was using on his eponymous
tube. Lenard answered apologetically that the machinist he was using was having trouble
enough supplying his own needs, but nonetheless, “I permit myself to send you two
sheets from my supply.”

Three years after Roentgen announced his discovery, Lenard wrote him a letter, declaring,
“I was particularly happy to know for sure what I had never had reason to doubt, that
you are friendly toward me. I was often afraid it could have been otherwise, and I
would have been sorry for that.” Absolving himself from any “polemics” that may have
come to Roentgen’s attention, Lenard continued, “Because your remarkable discovery
caused such remarkable attention in the farthest circles, my modest work also has
come into the limelight, which was of particular luck to me, and I am doubly glad
to have had your friendly participation,
especially through the presence of the x-ray
discovered by you
[italics mine].” He acknowledged that he had erred by presuming the observed effects
were due to cathode rays rather than X-rays. By giving Roentgen credit for the initial
discovery, Lenard provided history with a literal smoking gun that went against Lenard’s
later assertions that he was the discoverer of X-rays.

For his part, Roentgen portrayed a similar tone of collegiality and respect. A letter
to Lenard written in April 1897 expressed disappointment at his not being in Wuerzburg
to receive Lenard when the younger man unexpectedly came to visit. “I hope there will
soon be another opportunity,” Roentgen wrote. “For the receipt of prizes and medals
we several times have had reason for mutual congratulations. . . . Be assured that
I am very happy that my work has found such a ready recognition from you.”

Roentgen further apologized for “untimely newspaper articles” written by a former
assistant and close friend, Ludwig Zehnder, whom he had known since his days as a
student. He had complained in a letter to Zehnder about rumors to the effect that
it was not he, Roentgen, who had discovered the X-ray but an assistant or
diener
. He now wrote Lenard that he had mentioned Lenard’s name only in passing and that
he was “innocent as a newborn child and furious about it.”

Curiously, while Roentgen’s will ordered the destruction of his papers after his
death in 1923, he insisted that his correspondence with Lenard be preserved in a safe
at the University of Wuerzburg, presumably over concerns about the younger man’s claims
to the historical provenance of X-rays. It was well that he did. During the 1930s,
the years of Lenard’s greatest influence with the Nazi hierarchy, fears arose among
Roentgen’s Wuerzburg colleagues that pro-Lenard elements might seek to destroy the
letters. Authorities at the Institute made photocopies and sent them to sympathetic
scientists in other locales for safekeeping.

Their caution was well founded. As Lenard’s political star ascended, he became more
assertive in his claims of primacy regarding the discovery of X-rays. The scientific
establishment of the Third Reich sought to revise the history surrounding the events
of 1895. In 1935, an article by Johannes Stark concluded that Roentgen had done little
that was original. Rather, he had merely followed in the footsteps of Lenard. Assistant
professor Friedrich Schmidt, working under Stark, who by then had become president
of Berlin’s powerful Reich Physical and Technical Institute, also sided with Lenard.
He concluded that despite a lack of physical evidence, Lenard had made notes indicative
of his having recognized X-rays for what they were prior to Roentgen’s first publication.

Roentgen believed that his receiving the Nobel Prize for discovering X-rays precipitated
Lenard’s envy, but there may have been multiple factors at work. Given his suspicious
nature, Lenard may well have held a grudge over Roentgen’s letter to Zehnder, believing
that, despite his disclaimer, Roentgen had written negative comments about him that
later found their way into the public sphere. Even more critically, as was evident
with his envy of Einstein’s accolades, he almost certainly made resentful comparisons
between Roentgen’s public acclaim and his own. Even his own Nobel Prize failed to
salve the hurt he felt over the recognition accorded Roentgen. He belittled Roentgen’s
contributions in his Nobel Lecture and took the position that “anyone who was wide
awake and using a Lenard tube could have discovered the X-rays.”

If Lenard’s claims of primacy depend on Roentgen having used a Lenard tube that evening
in 1895 when he intuited X-rays, then they lack supporting evidence. The type of tube
Roentgen was using when he made the leap from observation to discovery is unknown.
An investigation of purchasing records shows that the University of Wuerzburg Institute
of Physics bought only one Lenard tube in 1895, but at the same time acquired a number
of Hittorf and Crookes tubes. The type of tube Roentgen employed the night of November
8, 1895, remains a point of contention.

Given Lenard’s statements concerning the inevitability of Roentgen’s discovery, why
didn’t he discover X-rays? According to Lenard’s laboratory workbooks, it appears
he had, on occasion, observed what he believed to be cathode rays causing imprints
on photographic plates. He also had witnessed plates fluorescing at distances greater
than would be expected of cathode rays and after traversing objects that would have
been expected to stop their less energetic passage.

Lenard gave four reasons why he missed out on being the discoverer of X-rays, three
of which were parroted by Stark in a 1935 publication when Stark and Lenard were at
the peak of their influence. That the items are worded nearly identically suggests
that Lenard colluded with Stark in making his own case:

1. During that period when he was serving a sequence of temporary appointments, he had
   changed institutions so frequently that he had not had the time to settle in and conduct
   his experiments as he would have liked;
   

2. At the time, he was using a tube encased in tin to exclude light emissions, rather
   than the cardboard used by Roentgen; the tin might have absorbed more of the X-rays,
   thus reducing their intensity;
   

3. He was at the mercy of Professor Hertz. The professor preferred he use a cheaper substance—keton
   (pentadecylparatolylketon), rather than barium platinocyanide—for his investigations.
   In fact, experiments conducted by Roentgen validated the seriousness of this shortcoming.
   Roentgen found that although keton fluoresced remarkably well under the bombardment
   of cathode rays, the material was wholly unresponsive to X-rays;
   

4. His cathode ray tube was poorly made by the glassblower, Louis Mueller-Unkel, whereas
   Roentgen’s tube had been made perfectly. In this regard, Lenard again blamed Hertz
   for his stinginess. Lenard wrote in his autobiography that he had approached his professor
   about purchasing a better tube. While Hertz had not said “no” outright, he clearly
   was unconvinced, telling the young man to go forward with the purchase only if he
   felt that the new tube would truly be worth the expense.
   

These last two explanations require further scrutiny. The half-Jew Hertz had prevented
him from having been the first to observe X-rays and reap the recognition that had
been accorded Roentgen. On the other hand, despite Hertz’s racial heritage, his story,
at least, is included among Lenard’s summaries in his book about the lives and scientific
works of “great men.” The biographies of neither Roentgen nor Einstein are among the
sixty-one selected.

As Hitler’s chief scientific advisor, Lenard remained a powerful force in German
academic politics and among the scientists of the Third Reich long after his 1933
retirement from his directorship of the University of Heidelberg Institute of Physics.
To insinuate doubt about the authenticity of Roentgen’s claims, he repeatedly raised
the question: why had Roentgen insisted on his executors burning his research notebooks
and other papers upon his death? Subsequent articles in Nazi periodicals like
Voelkischer Beobachter
and
Das Schwarze Korps
—the weekly publication of the SS—beat the drum for official recognition of Lenard
as the discoverer of X-rays until the Reich happily complied.

The Nazis did their best to eradicate the memory of Roentgen’s work and replace it
with an ersatz history that lauded one of their own. In 1944, the same Physical and
Medical Society of Wuerzburg, before whom Roentgen first presented his discovery,
made application to the Minister of the Reichspost (the German postal service), Wilhelm
Ohnesorge, requesting that the Reich design a stamp honoring the fiftieth anniversary
of Roentgen’s discovery. Ohnesorge was coincidentally a physicist who had trained
under Lenard. The request was denied.

In 1945, as American troops advanced toward Berlin during the final days of World
War II, Lenard fled Heidelberg. Along with Stark, he had been one of the point men
involved in enforcing laws forbidding the employment of Jews in German universities.
He was certain that those charged with seeking out and detaining Nazi war criminals
would be on the lookout for him. Surprisingly to Lenard, they either were not looking
for him or were oblivious of his whereabouts. He remained at large for nearly two
months in the tiny Badensian farming village of Messelhausen before turning himself
in to authorities and being placed under house arrest.

A little more than a month later, Lieutenant Colonel Lewis E. Etter, an American
physician of the U.S. Army Medical Reserve Corps, sat in the anteroom of Lenard’s
cottage. Doctor Etter had requested and been given permission through military channels
to conduct two interviews of Philipp Lenard about his relationship with Wilhelm Conrad
Roentgen, the man credited everywhere except Nazi Germany with discovering X-rays.
Lenard’s claims to the contrary had come up during a trip to Roentgen’s laboratory
in Wuerzburg, earlier in the year. Etter’s interest in Lenard was academic. While
stationed in England, early in the war, he had made an extensive study of radiation
physics. Later, he served as chief of radiology at several military medical installations
in Europe. He was only months away from resuming his civilian life as a neuroradiology
fellow and an instructor in radiology at the University of Pittsburgh. In time, Etter
would become a leading expert on the radiographic anatomy of the skull.

On September 20, 1945, Etter sat enveloped in an overstuffed chair beside a dark
wood table, lamplight reflecting from its oiled sheen. Only a moment earlier, he had
closed the thick volume lying beside him. From his first interview of Lenard two weeks
earlier and after reading parts of Lenard’s
Deutsche Physik
, which the aged scientist had suggested he borrow from a local physician, Etter had
learned the essence of the old man’s dispute with Roentgen. He’d found a handwritten
note, signed by Lenard, on the flyleaf of the book:

To be found in this volume, my reckoning with Roentgen, held back for almost fifty
years. . . . Again, I speak now only because of my ineradicable desire for truth.
For fifty long years one was so dull as never to care seriously about the actual coming
about of a rather much noticed and practically used discovery.