the source of light in the experiments, a spark gap, has a
variation of intensity of about 25 percent, and that source
intensity variation precluded accurate measurements.
Next, Wood was shown the experiment that supposedly
demonstrated the deviation of the N-rays by an aluminum
prism. When the lights were turned down low, Wood secretly
lifted the aluminum prism from the spectroscope, and
Blondlot continued to measure the spectrum of the N-rays,
noting no change in the dispersion. Before the lights
were turned on again, Wood carefully replaced the
aluminum prism in the spectroscope.
The next morning, Wood submitted a
paper to Nature (London), in which he
summarized his conclusions on N-rays.
Without naming Blondlot, he stated that
he visited the laboratory in which most of
the N-ray experiments were carried out
and that he had removed the aluminum
prism from the spectrometer. He stated
that this act “did not seem to interfere in
any way with the location of the maxima
and minima in the deviated ray bundle,” and
concluded “that all the changes in the luminosity
or distinctness of sparks and phosphorescent screens
(which furnish the only evidence of n-rays) are purely imaginary.” Finally, Wood proposed experiments that could be used
to settle the issue beyond doubt; they were never performed.
Wood’s report was published in Nature on September 29,
1904. The fallout was severe, especially for Blondlot. Subsequent to Wood’s failed verification, only two papers on N-rays
were published in Comptes rendus.
The French journal Revué Scientifique proposed a blinded
experiment to Blondlot. They offered to send him two boxes that
were sealed and identical in every way, with two exceptions; one
contained a piece of tempered steel, while the other included
a piece of lead. Blondlot’s task was to determine which box
emitted the N-rays. He refused to take part. Following the
N-ray debacle, Blondlot continued to work at the University of
Nancy until his early retirement in 1910. He died in 1930; no
one has reported on the existence of N-rays since then.
In 1980, Irving M. Klotz, a professor of chemistry and
biochemistry, molecular biology and cell biology at Northwestern University, wrote an article in Scientific American, in which
he claimed that Blondlot’s discovery of N-rays was a mistake,
not a hoax. I suggest that the reader peruse the articles of both
Wood and Klotz (which are cited in the references) and decide
for themselves. (If readers are still perplexed about how the
N-ray affair could occur, I suggest that they Google the terms
“polywater” and “cold fusion.”)
and ultraviolet light. He invented a filter that transmitted
ultraviolet light but was opaque to visible light. It came to
be known as Wood’s filter. He also developed Wood’s lamp,
a useful source of ultraviolet light that is used in clinical
dermatology and analytical chemistry and geology.
In addition to his masterpiece, Physical Optics, Wood
and Arthur Train co-authored a science fiction book
called The Man who Rocked the Earth. Wood showed his
humorous side in a book of nonsense verse that he also
illustrated: How to Tell the Birds from the Flowers
and Other Woodcuts. Wood continually found
joy and playfulness within science.
Wood was nominated for the Nobel Prize
in Physics with C.V. Raman in 1930. He
received honorary degrees from Berlin
University, Clark University, the University
of Birmingham and Edinburgh Univer-
sity. He received the Rumford Medal of
the Royal Society, and a crater on the far
side of the moon is named after him. He was
a member of American National Academy of
Science, the Physical Society, the London Physi-
cal Society, the Royal Swedish Academy, the Royal
Swedish Academy, the London Physical Society and the
Indian Association for the Cultivation of Science in Calcutta.
OSA conferred upon Wood the Frederick Ives medal for distin-
guished work in physical optics in 1938. Wood served as both
vice-president and president of the American Physical Society.
In 1938, at the retirement age of 70, Wood changed his
appointment at Johns Hopkins University from head of the phys-
ics department to research professor of physics. Two years later,
the National Academy of Sciences presented him with the Draper
Medal for work performed since his retirement. Wood died in
Amityville, N. Y., on August 11, 1955, at the age of 87. He will
always be remembered as an inventive genius who understood
intuitively that creativity and science are not mutually exclu-
sive. Indeed, to the greatest minds, they go hand in hand. t
Wood will always be remembered as an inventive genius.
Barry R. Masters ( firstname.lastname@example.org) is an OSA Fellow and SPIE
Fellow. He is with the department of biological engineering at the
Massachusetts Institute of Technology in Cambridge, Mass., U.S.A. Member
An honored inventor and writer
Wood was a creative experimental physicist and author. Aside
from his remarkable corpus of spectroscopic studies on resonance radiation, he produced photographs in both infrared
[ References and Resources ]
>> R. W. Wood. “The n-Rays,” Nature 70, 530-1 (1904).
>> R. W. Wood. How to Tell the Birds from the Flowers and Other Woodcuts,
Duffield and Co, 1917.
>> V. Weisskopf. “Zur Theorie der Resonanzfluoreszenz,” (Göttingen Diserta-tion), Annalen der Physik 5( 9), 23-66 (1931).
>> A.C.G. Mitchell and M. W. Zematsky. Resonance Radiation and Excited
Atoms, London, Cambridge University Press, 1934.
>> W. Seabrook. Doctor Wood, Modern Wizard of the Laboratory, New York,
Harcourt, Brace and Company, 1941.
>> G. Meyer-Schwickerath. Ber. Dtsch. Ophthalmol. Ges. 55, 256–9 (1949).
>> R. W. Wood. Physical Optics, Third Edition. New York, Dover Publications, 1967.
>> I.M. Klotz. “The N-Ray Affair,” Scientific American, May 1989, 168-75.
>> M. W. Jackson. ”Spectrum of Belief, Joseph Von Fraunhofer and the Craft
of Precision Optics,” Cambridge, The MIT Press, 2000.