subtend no sensible angle. Thus, visibility
is only a question of brightness and has
nothing to do with resolution!
Resolution is only important in
distinguishing a double star or details on
the surface of planets. Rayleigh discussed
the similar situation of a bright line; if a
line is bright enough, it will be visible no
matter how narrow. However, its width
will be illusionary, depending on the
resolution of the optical device. Notably,
Rayleigh correctly stated that it may vary
with the character of the detail of the
object (e.g., points, lines, planes).
Colors of the sea and sky
In a 1910 publication, Rayleigh stated
that the dark blue color of the deep sea
had nothing to do with the color of the
sea. Instead, he believed it was simply the
blue of the sky seen by reflection. Not a
single equation appeared in these papers.
Of course, C.V. Raman disagreed, and
Raman’s work eventually resulted in
his discovery of the Raman effect and a
Nobel Prize (see Opt. Photon. News 20,
40-5, March 2009).
The optical character of
brilliant animal colors
In his 1919 paper, Rayleigh reported
having been struck by the brilliant
colors displayed by birds, butterflies and
beetles. He noted that these organisms
exhibit a metal-like luster, even though
they are composed of non-metallic
substances. In an example of his great
physical insight, Rayleigh posited that
periodic structures below the resolution
of the light microscope may be responsible for the metal-like appearance of these
organisms. (To learn more about optical
filters in nature, check out Opt. Photon.
News 20, 22-7, Feb. 2009).
Zone plates are based on diffraction—
in contrast to lenses, which are based
on refraction. The resolving power of a
zone plate is a function of the number
of zones in the plate. Rayleigh suggested an improvement in the design of
these plates. Instead of blocking every
other zone, one could shift the phase
Abbey, a memorial
for Rayleigh is located
close to that for
that suggests their
affinity for one
another in life.
of alternate zones by 180 degrees. This
is called a phase-reversal zone plate; it
would more efficiently utilize the incident light. R. W. Wood was the first to
construct such zone plates.
Honors and late life
Rayleigh was widely recognized for his
scientific eminence; he achieved the
highest scientific honors in Britain and
the world. He was intimately associated with the Royal Society of London
in the capacity of fellow, secretary and
president. He also received the Copley
Medal and the Rumford Medal from
the Royal Society. He served as Chancellor of Cambridge University and a
Privy Councilor. In addition, he received
the Order of Merit (conferred by King
Edward VII in 1902), the Nobel Prize
in Physics, and honorary degrees from
many universities as well as honorary
membership in many national academies
of science worldwide.
Rayleigh was 77 when he died from
a heart attack on June 30, 1919. He
continued to work until the end of his
life. In fact, five days before he died, he
dictated a scientific paper to his wife.
In the 50 years of Rayleigh’s scientific
career, he published many papers that
are available as six volumes of Rayleigh’s
Collected Scientific Papers.
Rayleigh was buried in the churchyard of the family estate at Terling. In
Westminster Abbey, a memorial for
Rayleigh is located close to that for
Thomas Young—a fitting juxtaposition
that suggests their affinity for one
another in life. Sir J.J. Thompson,
Rayleigh’s successor as Cavendish
Professor at Cambridge and professor
of natural philosophy at the Royal
Institution, spoke these words at
the ceremony to honor Rayleigh in
Westminster Abbey: “There are some
great men of science whose charm
consists in having said the first word on
a subject, in having introduced some
new idea which has proved fruitful;
there are others whose charm consists
perhaps in having said the last word on
a subject, and who reduced the subject
to logical consistency and clearness. I
think, by temperament, Lord Rayleigh
really belonged to the second group.”
Barry R. Masters (brmail2001@yahoo.
Member com), OSA Fellow, SPIE Fellow, is with
the department of biological engineering, M.I. T.,
Cambridge, Mass., U.S.A.
[ References and Resources ]
>> P. W. Bridgman. Dimensional Analysis, New
Haven, Yale University Press, 1920.
>> W. Ostwald. Die Arbeiten von Agnes Pockels
über Grenzschichten und Filme, Kolloid-
Zeitschrift, LVIII Band, Heft 1, 1-8, 1932.
>> J. W.S. Rayleigh. The Theory of Sound,
Volume One, Two, New York, Dover Publications, 1945.
>> J.N. Howard. “John William Strutt, third
Baron Rayleigh,” Appl. Opt. 3( 10), 1091-101
>> J.N. Howard. “The Rayleigh Notebooks,”
Appl. Opt. 3( 10), 1129-33 (1964).
>> V. Twersky. “Rayleigh Scattering,” Appl. Opt.
3( 10), 1150-62 (1964).
>> R.J. Strutt. Life of John William Strutt, Third
Baron Rayleigh, Madison, The University of
Wisconsin Press, 1968.
>> C.H. Giles and S.D. Forrester. “The origins
of the surface film balance,” Chemistry and
Industry, 43-53 (January 9, 1971).
>> C. Tanford. Ben Franklin Stilled The Waves.
Durham, Duke University Press, 1989.
>> C.L. Braun and S.N. Smirnov. “Why is water
Blue?,” Journal of Chemical Education 70( 8),
>> Lord Rayleigh. The Collected Optics Papers
of Lord Rayleigh, Part A,B, Washington, Optical Society of America, 1994.
>> B.R. Masters. “The History of Perturbation Theory from Astronomy to Quantum
Mechanics,” in: B.R. Masters, P. T.C. So,
Handbook of Biomedical Nonlinear Optical
Microscopy, New York, Springer Verlag,