Ewing, William Maurice
EWING, WILLIAM MAURICE
(b, Lockney, Texas, 12 May 1906;d.Galveston, Texas, 4 May 1974)
geophysics, oceanography, seismology.
Ewing hardly ever used the name William, preferring to go by the name Maurice. His parents were Floyd Ford Ewing, a farmer who was also a dealer in hardware and farm implements, and Hope Hamilton Ewing. The fourth of ten children, Ewing grew up as the eldest of seven because his three older siblings died at very early ages. Hope Ewing wanted all her children to be educated, and all but one obtained a university education, John, the youngest, became a well-known geophysicist in his own right. He worked with Maurice at Lamont Geological Observatory and later moved to Woods Hole Oceanographic Institution, where he chaired the department of geology and geophysics.
Ewing was one of the most important exploratory geophysicists who took on the task of finding out about the ocean floor. He was extremely ambitious and had the energy and intelligence to match. He began taking seismic refraction measurements in the ocean in 1935. During World War II, while at Woods Hole Oceanographic Institution, he did pioneering work on the transmission of sound in seawater. In 1949 Ewing was appointed director of Lamont Geological Observatory, which became Lamont-Doherty Geological Observatory in 1969. He remained the director until 1972, when he returned to Texas to become the founding chief of the earth and planetary sciences division of the Marine Biomedical Institute of the University of Texas at Galveston.
Ewing turned Lamont into one of the leading, if not the leading, institutes of marine geology and geophysics. He and the institution were extremely productive in gathering all sorts of data about the seafloor. Ewing was a master at getting the most out of his co-workers and students, as well as his ships and equipment. His work on interpreting surface waves, done with Frank Press, led to the first well-founded estimate of the depth of the Mohorovičić discontinuity under the ocean floor; and the data bank he established at Lamont-Doherty played a crucial role in the confirmation of seafloor spreading and plate tectonics in the late 1960’s and early 1970’s.
Ewing became a member of the National Academy of Sciences in 1948 and of the American Philosophical Society in 1959, and a foreign member of the Royal Society of London in 1972. He was also an honorary or foreign member of the Geological Society of London (1964), the Royal Astronomical Society (1964), the Wollaston Medal of the Geological Society of London (1969), the American Association of Petroleum Geologists (1968), and the Royal Society of New Zealand (1970). Among the numerous scientific prizes Ewing received were the Arthur L.Day Medal of the Geological Society of America (1949), the Agassiz Medal of the National Academy of Sciences (1955), the William Bowie Medal of the American Geophysical Union (1957), the Vetlesen Prize (1960), the Cullum Geographical Medal of the American Geographical Society (1961), the gold medal of the Royal Astronomical Society of London (1969), and the Walter H. Bucher Medal of the American Geophysical Union (1974).
Ewing was vice president of the Geological Society of America from 1953 until 1956, president of the American Geophysical Union from 1956 to 1959, and vice president (1952–1955) and president (1955–1957) of the Seismological Society of America.
Following his mother’s wishes, Ewing received a sound public school education in Lockney and in 1922 was awarded the Hohenthal Scholarship to Rice Institute in Houston. Texas. Originally he was denied the scholarship; but his mathematics teacher at Lockney High School wrote to Rice, explaining that Ewing was the best mathematics student he had yet encountered.
At Rice, Ewing had to work in order to support himself. At first he worked in an all-night drugstore, then assisted in classes and worked in the library. He also found time to play the trombone in the marching band. While performing one day, he was noticed by a coed named Avarilla Hildenbrand; married 31 October 1928, they had one son and were divorced in 1941. Despite his heavy work load outside of class, he did well at Rice.
Ewing first majored in electrical engineering but switched to physics and mathematics, for he found both the subjects and instructors more exciting than the engineering courses or faculty. He was greatly influenced by H. A. Wilson, a rather unorthodox physicist who had been at the Cavendish Laboratory. Wilson was able to draw prestigious scientists to Rice for his weekly colloquia series, and thus Ewing had the opportunity to meet a number of important physicists. He took no undergraduate courses in geology; indeed, he never took a geology course. He obtained field experience during his summer vacations as part of a crew prospecting for oil in the shallow lakes of Louisiana. This was his first exposure to underwater exploratory geophysics.
In 1926, while still an undergraduate, Ewing published his first scientific paper, ‘‘Dewbows by Moonlight.” He received the B.A. in 1926, and that fall he became a graduate student in the physics department at Rice. He obtained the M.A. in 1927 and the Ph.D. in 1931. Part of his dissertation, “Calculation of Ray Paths from Seismic Travel-Time Curves,” was published in two papers written with Lewis D. Leet, then director of the seismological station at Harvard.
In 1929 Ewing was hired as an instructor in physics at the University of Pittsburgh and a year later left Pittsburgh for a similar position at Lehigh. During his first several years at Lehigh, he had to teach a number of elementary physics courses but still managed to do research in geophysics and present papers at meetings of the American Geophysical Union (1931, 1934). Although this work did not deal with important topics, he developed a fuller understanding of the techniques of explosive seismology. In November 1934 Ewing’s first real opportunity to engage in potentially significant research came when Richard Field and William Bowie visited Lehigh. Bowie was chief of the division of geodesy of the Coast and Geodetic Survey; and Field, professor of geology at Princeton, was the major force behind the founding of the American Geophysical Union’s Committee on the Geophysical Study of the Ocean Basins.
Most likely knowing of Ewing’s work through hearing him speak at meetings of the American Geophysical Union, Bowie and Field suggested that Ewing use explosive seismology to investigate the continental shelf. He agreed, and they decided that he should investigate the region between Cape Henry, Virginia, and the edge of the continental shelf. Although the first attempt did not yield any geological results, it convinced Ewing that he had the technical knowledge to use explosive seismology at sea. Through the influence of Field, he got the use of the R.V. Atlantis, which belonged to the Woods Hole Oceanographic Institution. Ewing undertook the project in October 1935, and his study indicated that the seafloor from just off Virginia to the edge of the ocean depths was covered by sediments 3, 800 meters thick.
Ewing continued seismic shooting in shallow water throughout the remainder of the 1930’s and by 1939 extended his seismic refraction surveys to the shallow waters off Bermuda. In all, Woods Hole provided him with forty-five days of shared time aboard the Atlantis during this period. It was on one of these expeditions that Ewing met Edward Bullard. He also, probably through Field’s influence, worked with Harry Hess aboard the submarine U.S.S. Barracuda. In 1936 they traced the negative gravity anomaly associated with the Puerto Rico Trench around the island are of the Lesser Antilles. The anomaly had been discovered in 1926 by the Dutch geophysicist Felix Vening Meinesz, who invented a pendulum apparatus for taking gravity measurements at sea from aboard submarines. Obtaining gravity measurements of the seafloor became one of Ewing’s major interests, and he continued to work in the field for most of his life.
During World War II, Ewing, on a leave of absence from Lehigh, went to Woods Hole Oceanographic Institution, where he was a research associate from 1940 to 1944. He took Allyn Vine and J. Lamar (Joe) Worzel, two of his former graduate students, with him; and they and Columbus Iselin, director of Woods Hole, wrote a manual for the U.S. Navy entitled Sound Transmission in Sea Water. Iselin was impressed with Ewing and his students. Not only were they intelligent but they also worked night and day, seven days a week.
During this time Ewing and his co-workers discovered a low-velocity sound channel in the ocean. It is at a depth of 700–1, 300 meters and is called the SOFAR (Sound Fixing and Ranging) channel. The SOFAR channel traps sound waves, and as a result sounds can be transmitted over tremendous distances within this low-velocity tunnel. Ewing found that he could record the sound from the explosion of a small charge dropped off the west coast of Africa as far away as the Bahamas. Needless to say, the U.S. Navy found this discovery important. Ewing met his second wife, Margaret Kidder, at Woods Hole. They were married 19 February 1944 and had two sons and two daughters.
In 1944 Ewing was offered an assistant professorship in the geology department at Columbia University. He accepted and moved to New York City in June 1946, and became a full professor in 1947. The following year the widow of Thomas Lamont, a well-known New York financier, gave Columbia their 155-acre estate, located north of New York City on the west bank of the Hudson River in Palisades, New York. Columbia offered Ewing the use of the estate along with the $250, 000 included in the original gift. Around the same time the Massachusetts Institute of Technology asked Ewing to join its staff and offered to provide him with a similar estate and financial support. Ewing and some of his group went to MIT, listened to the offer, and unanimously voted to stay at Columbia.
Even though Ewing had his own oceanographic institute and a corps of excellent researchers, he still needed his own ship. Although he had some difficulty convincing Columbia University to purchase a ship, in 1953 it bought Vema for $150, 000. Having his own ship made it much easier for Ewing to design instruments and secure outside funding for oceanic exploration.
Early in 1949, after he settled into Lamont but before the purchase of Vema, Woods Hole gave Ewing the simultaneous use of two ships. This was a long-standing desire of Ewing’s, since it would allow him to record seismic refraction shots of requisite power and separation to determine the depth of the Mohorovičić discontinuity (Moho) between the crust and the mantle under the Atlantic Ocean. At the time, it was generally felt that the depth of the discontinuity under the oceans was less than under the continents, but the issue was unresolved.
Ewing and his co-workers found the Moho to be five kilometers beneath the ocean floor. There were, however, two problems with the study. One was practical: the results were, strictly speaking, indicative of the depth of the Moho in one small area of the Atlantic Basin. It would take years to get enough shots to determine if the five-kilometer depth was typical of the whole Atlantic and other ocean basins. The other was that the five-kilometer depth was considerably less than previous estimates that had been drawn primarily from time-travel studies of the dispersion of earthquake surface waves over oceanic paths. These studies indicated values more in concert with Beno Gutenberg’s estimates.
Ewing and Frank Press, one of his students, found a single solution to both problems. They realized that they had to begin their own analysis of earthquake surface waves. Perhaps they could resolve the conflict and, if successful use analyses of surface waves as a quick way of finding out the depth of the Moho under any ocean without having to go to sea. As a first step they constructed and installed seismographs at Lamont that were capable of getting reliable travel times for surface waves. They also examined previous analyses and realized that they failed to take into account the effect of water and seafloor sediments on surface waves. Correcting the mistake, they found that their analysis of surface wave distribution yielded the five-kilometer value for the depth of the Moho. He and Press submitted their first article on the subject on 1 August 1949.
This discovery of a fundamental difference between oceanic and continental crust was Ewing’s most important specific piece of work. It was unexpected, and its consequences for geological thought were enormous. It also eliminated the need to take thousands of ship-to-ship seismic shootings in order to determine, point by point, the thickness of the oceanic crust—a task that would have taken years to complete.
Ewing remained director of Lamont for twentythree years, resigning in 1972. His greatest professional achievement was molding Lamont into a superb oceanographic data-gathering institution. By deciding to keep his laboratory, Lamont’s ships, at sea for almost the entire year, he built up an enormous data base. Rather than require that the data from one voyage be analyzed before beginning another, Ewing decided to stockpile data concerning all sorts of parameters. He also insisted that any data collected by Lamont ships be available to anyone at Lamont. The policy at most other institutions was to let the person directly responsible for collecting the data or the chief scientist of the cruise view the data as his private property. Ewing created a much more efficient and useful communal data base. Moreover, Ewing encouraged and demanded the most from his students and co-workers, and he taught by example. This provided Lamont with the largest oceanographic data base in the world while he was director and enabled its personnel to confirm, in 1965 and 1966, the key hypothesis thatled to plate tectonics and the revolution in the earth sciences during the late 1960’s and early 1970’s.
It is somewhat ironic, but to Ewing’s credit, that the data gathered by Lamont played such a crucial role in the confirmation of seafloor spreading and plate tectonics. Ewing was strongly opposed to the concepts of continental drift and seafloor spreading, although he reluctantly accepted them at the very end of 1966.
The variety of innovative data-gathering techniques developed or improved at Lamont, and the resulting discoveries, were astounding. Ewing, interested in discovering the nature of seafloor sediments, developed seismic reflection shooting at sea and began using it as early as 1949. Seismic reflection allows the determination of small discontinuities in seafloor sediment. Ewing and others at Lamont developed powerful echo sounders that were capable of differentiating layers of sediment. At first a single hydrophone was lowered over the side of the ship to record the shots. Later, hydrophones were towed behind the ship and 0.2-kg. charges were thrown overboard. Around 1962 Ewing began using “sparkers” and “air guns” to produce the sounds. The sparker produces sound by an underwater spark, and the air gun is a container filled with air, kept at a pressure of 150 atmospheres, that is suddenly released through a valve. Ewing and his brother John, who was responsible for much of this work, mapped the various sediment layers, especially in the northern Atlantic, throughout the 1960’s.
During the early 1950’s Ewing and two of his co-workers, Bruce Heezen and David Ericson, confirmed the existence of turbidity currents, which had been hypothesized by American geologist Reginald A. Daly in 1933. Daly proposed that underwater currents—he called them “density currents”— caused the formation of submarine canyons, which were known to cut through the continental slope at the mouths of major rivers. In 1938 the Dutch sedimentologist Philip H. Kuenen developed a lab oratory model of density currents (he called them “turbidity currents”) to show that they could cut through channels and deposit sediment evenly over the bottom of his laboratory tank.
In 1947 Ewing and his co-workers had discovered the existence of a great abyssal plain between Ber muda and the Mid-Atlantic Ridge. They were as tonished at the flatness of the plain, and the few cores they took indicated that the plain was covered by relatively recent sediment, nothing older than the Eocene. Two years later they traced the Hudson Canyon 200 miles beyond the continental slope and 15, 900 feet beneath the surface. This convinced them of the existence of turbidity currents, which in turn explained the extent of the canyon, the flatness of the abyssal plain, and the recency of the deposits. In 1952 Ewing and Heezen cited turbidity currents in explaining why the 1929 earthquake on the Grand Banks had sequentially broken more than a dozen submarine cables.
Lamont was also responsible for the discovery of the rift valleys that run along the axes of most of the midoceanic ridges. In 1952 Marie Tharp, a cartographer who worked primarily with Heezen, discovered a depression in three profiles of the Mid-Atlantic Ridge and suggested to Heezen the existence of a valley in the center of the ridge. By 1953 Heezen was convinced of the correctness of Tharp’s analysis. He had a contract with a cable company to determine why submarine cables often failed and had become interested in the location of earthquakes on the seafloor. He noticed that many of them occurred in the place where Tharp had hypothesized the existence of the rift valley. Ewing also was convinced, and in 1956 he and Heezen presented the discovery at a meeting of the American Geophysical Union. The discovery of the central rift valley and associated earthquakes was extremely important. Not only did it require that any theory about the origin of oceanic ridges explain the presence of the rift valley and shallow earthquakes, it also allowed oceanographers to trace the location of oceanic ridges throughout the world by examining seismological maps of oceanic ridges.
Ewing also thought it would be worthwhile to gather information about submarine magnetic fields, and in 1952 he decided to have his ships tow an airborne magnetometer that had been designed by Victor Vacquier for the detection of submarines. His work inspired other oceanographic institutions to undertake extensive geomagnetic surveys. Given Ewing’s plan to collect as much data as possible, however, the Lamont group continued to make magnetic profiles; and its profiles of the PacificAntarctic Ridge and the Reykjanes Ridge, analyzed by such Lamont personnel as Walter Pitman III and James Heirtzler, played a central role in the confirmation of seafloor spreading and the development of plate tectonics.
Ewing also stressed the collection of core samples of sediment on the ocean floor. He and his coworkers collected more cores than any other oceanic institution, and work on them led not only to the development of a theory about the cause of ice ages by Ewing and W. L. Donn, one of his students (1956) but also allowed Neil Opdyke, a paleomagnetist hired by Ewing, to trace the time scale of polarity reversal in seafloor sediments ten years later. This latter accomplishment was extremely important in confirming the existence of seafloor spreading and plate tectonics.
Ewing’s commitment to his work and the development of Lamont put a tremendous strain upon his private life. Although he cared deeply about his family, his second marriage ended in divorce in 1965. Later that year he married Harriett Green Bassett, who had been his secretary at Lamont. She continued to work at Lamont, and also worked for him after he went to the University of Texas at Galveston in 1972. Ewing died of a massive cerebral hemorrhage.
I. Original Works. Ewing was author or coauthor of more than 350 publications. The most comprehensive list is in the memoir by Bullard (see below). Among writings relevant to the account above are “Dewbows by Moon light,” in Science, 63 (1926), 257–258; “Geophysical investigations in the Emerged and Submerged Atlantic Coastal Plain. Part IV. Cape May, New Jersey, Section,” in Bulletin of the Geological Society of America, 51 (1940), 1821–1840, written with George P. Woollard and A. C. Vine; “Crustal Structure and Surface-Wave Dispersion,” in Bulletin of the Seismological Society ofAmerica, 40 (1950), 271–280, written with Frank Press; “Turbidity Currents and Sediments in the North Atlantic,” in Bulletin of the Association of Petroleum Geologists, 36 (1952), 489–511, written with D. B. Ericson and Bruce Heezen; “Turbidity Currents and Submarine Slumps, and the 1929 Grand Banks Earthquake,” in American Journal of Science, 250 (1952), 849–873, written with Bruce Heezen; “A Theory of Ice Ages,” in Science, 123 (1956), 1061–1066, written with W. L. Donn; “Mid-Atlantic Ridge Seismic Belt,” in Transactions of the American Geophysical Union, 37 (1956), 343 (abstract), written with Bruce Heezen; The Floors of the Oceans: I. The North Atlantic, Geological Society of America, Special Paper no.65 (New York, 1959), written with Marie Tharp and Bruce Heezen; “Seismic-Refraction Measurements in the Atlantic Ocean Basins, in the Mediterranean Sea, on the Mid-Atlantic Ridge, and in the Norwegian Sea,” in Bulletin of the Geological Society of America, 70 (1959), 291–318, written with John Ewing; and “Sediment Distribution on the Mid-ocean Ridges with Respect to Spreading of the Sea Floor,” in Science, 156 (1967), 1590–1592, written with John Ewing, which contains Ewing’s first endorsement, albeit a mild one, of seafloor spreading. The paper that best illustrates Ewing’s earlier views on continental drift, one not included in Bullard’s bibliography, is “The Atlantic Ocean Basin,” part of “The Problem of Land Connections Across the South Atlantic, with Special Reference to the Mesozoic,” which is article 3 in Bulletin of the American Museum of Natural History, 99 (1952), 87–91.
Harriet Ewing collected many of her husband’s private papers and gave them to the University of Texas. They are housed at the Harry Ransom Humanities Research Center at the University of Texas at Austin.
II. Secondary Literature. The best commemorative articles are Sir Edward Bullard, “William Maurice Ewing,” in Biographical Memoirs of Fellows of the Royal Society of London, 21 (1975), 269–311, expanded in Biographical Memoirs. National Academy of Sciences, 51 (1980), 119–193; and William L. Donn, “Memories of (William) Maurice Ewing: The Little Boy in the Candy Shop,” in EOS, 66 (1985), 129–130. Bullard’s is more comprehensive, but Donn’s offers an intimate and lively account of Ewing, of his and Donn’s development of their hypothesis about the cause of ice ages, and his reluctance to accept seafloor spreading and continental drift. William Wertenbaker, The Floor of the Sea (Boston, 1974), has captured Ewing’s own account of much of his life and gives the reader a feel for Ewing and his work; however, I believe that he sometimes fails to give Ewing’s co-workers proper credit for their contributions.
See also Henry Frankel, “The Development, Reception, and Acceptance of the Vine-Matthews-Morley Hypothesis,” in Historical Studies in the Physical Sciences, 13 (1982), 1–39; William Glen, The Road to Jaramillo (Stanford, Calif., 1982); Xavier Le Pichoon, “The Birth of Plate Tectonics,” in Lamont-Doherty Geological Yearbook for 1985/1986 (New York, 1985), 53–61; and Neil Opdyke, “Reversal of the Earth’s Magnetic Field and the Acceptance of Crustal Mobility in North America: A View from the Trenches,” in EOS, 66 , (1985), 1177.
William Maurice Ewing
William Maurice Ewing
American Geologist, Geophysicist and Physicist
William Maurice Ewing, known as "Doc" to his associates, was a pioneer in the development of techniques to study ocean basins, which at that time were still essentially a mystery. He also made fundamental contributions to the study of earthquake origins.
With a working scholarship, Ewing studied at the Rice Institute in Houston (1926-1931), earning a Ph.D. in physics. He had already become interested in ocean crust and sediment study during summer jobs prospecting for oil in the Gulf of Mexico with other future figures in marine geophysics—Albert D. Crary and H. N. Rutherford. In 1924 they were on a 22-foot (6.7 m) whaleboat throwing packages of explosive blasting gelatin over the side—a way of obtaining seismic reflection profiles of the continental shelf that was improved by Ewing. He taught physics in Pennsylvania, first at the University of Pittsburgh, then Lehigh, but was turning more toward marine geological research, conducting part-time work at the Woods Hole Oceanographic Institute in Cape Cod, Massachusetts. Because of his research in the travel of seismic waves through strata he was asked in 1934 by the U.S. Coast and Geodetic Survey and the American Geophysical Union to study the continental shelf of North America. At Woods Hole he took to the sea, developing methodical seismic survey procedures using seismic reflection and refraction techniques for the open ocean. From data gathered from the Atlantic basins, Mid-Atlantic Ridge, Norwegian, and Mediterranean bottom profiles, he showed the ocean floor crust to be much thinner than the continental crust. He also improved methods for studying gravitational anomalies over the ocean.
After World War II, during which he conducted important marine acoustical research for the U.S. Navy, Ewing accepted a position in the geology department at Columbia University in New York. At that time, money and land were donated to the school to start the prestigious Lamont Geological Laboratory (today the Lamont-Doherty Earth Observatory) in Palisades, New York. Ewing became its first director, remaining at the post for 25 years. One of his early wishes was that Lamont be an oceanographic institution as well. Ewing introduced the use of deep underwater photography and developed more seagoing seismic methods, involving earthquake waves to obtain oceanic crust topography. He introduced the use of sonar (propagated sound waves) for topographic soundings and the use of a submersible coring machine to take longer ocean sediment samples (the Ewing corer).
By 1952 Ewing was conducting extensive ocean sediment sampling. He directed research vessels to tow magnetometers to obtain measurements of changing magnetic fields. Sediment cores validated the phenomenon of trapped magnetic fields. During the International Geophysical Year (1957-1958) Ewing continued this research with his colleagues; they discovered a central rift valley associated with the Mid-Atlantic Ridge and confirmed their hypothesis that great mid-ocean ridges encircle Earth. Others took these leads to form the foundation for plate tectonic theory, which Ewing did not accept until relatively late. He did propose with other researchers, however, that earthquakes were associated with central oceanic rifts around the globe. He further hypothesized that sea-floor spreading was probably global and episodic.
Ewing devoted himself to data acquisition rather than theory—the first essential, the latter overabundant—yet his efforts were paramount to both. Many of his published works were collaborations with colleagues, such as Propagation of Sound in the Ocean (1948) and The Floors of the Oceans (1959). In 1972 he returned to his native Texas, joining the University of Texas at Galveston. He received many scientific awards. Ewing was honored on his death by the American Geophysical Union, when it instituted the Maurice Ewing Medal in 1974, honoring individuals for work in marine geophysics and technology.
WILLIAM J. MCPEAK
PROMOTING GENDER EQUITY IN SCIENCE EDUCATION
During the last decades of the twentieth century there was an increasing call to promote gender equity in college and secondary school science and mathematics classrooms. Compared to their male counterparts, many studies continued to show that disproportionately fewer female students took elective science courses at the secondary school or college level. Consequently, disproportionately fewer women pursued university degrees or careers in mathematics, science and engineering.
Despite continual gains started in the early 1970s, near the end of the twentieth century women still comprised a relatively small percentage (15%) of the scientists and engineers in the United States and only about 10% of university-level science faculty. In 1991 the American Association of University Women began a series of studies and reports investigating the causes of the gender gap in science and science education. The AAUW studies set out, in part, to debunk disputed data that suggested a biological basis to the gender gap in scientific achievement. In 1996 the National Science Foundation also undertook studies of student proficiency in science. The NSF report of its findings ultimately suggested significant differences between male and female secondary school students with regard to achievement in, and attitudes toward, math and science regardless of race, socioeconomic status, and other demographic factors. The AAUW claimed that its studies substantiated perceptions that classroom level gender bias damaged female students' self-esteem, school achievement, and career aspirations. Among the factors consistently identified in the AAUW reports as perpetuating the gender bias was differential treatment by teachers that steered girls away from math and science courses.
William Maurice Ewing
William Maurice Ewing
The American oceanographer William Maurice Ewing (1906-1974) was a leader in modern earth science research, especially in the applications of geophysics to oceanography.
Maurice Ewing was born in Lockney, Texas, on May 12, 1906. He was the fourth of 10 children of Floyd Ford Ewing, a farmer and hardware merchant, and Hope Hamilton Ewing. His older siblings died at very young ages, so he grew up as the eldest of seven. He preferred to be known as Maurice, rather than William. His parents stressed the importance of education, and Ewing studied diligently and received a scholarship to college. Working at night to support himself, he received his bachelor's (1926), master's (1927), and doctoral (1931) degrees from Rice Institute in Houston. He first majored in electrical engineering and later switched to mathematics and physics, which he found more interesting. One physicist, H. A. Wilson, had a major influence on Ewing. Wilson held a weekly series at Rice attended by many prestigious scientists who made a big impression on Ewing.
Won Geological Grant
Ewing was instructor in physics at the University of Pittsburgh from 1929 to 1930. He moved to Lehigh University as instructor of physics in 1930, becoming assistant professor in 1936 and associate professor of geology in 1940. Probably the most important event of his professional life occurred in 1935, when a committee of distinguished geologists asked if he would undertake the task of applying the techniques of geophysics to the ocean areas. He jumped at the chance and with their support obtained a grant from the Geological Society of America for a classic refraction study of the structure of the Continental Shelf off the East Coast of the United States. This was quickly followed by a successful gravity-measuring cruise on the Barracuda, using the newly developed gravity pendulum apparatus introduced by F.A. Vening Meinesz.
With the aid of some of his students, Ewing built ocean-bottom cameras and automatic apparatus for making seismic refraction measurements at the bottom of the deep-ocean basins. Several seismic measurements had been successfully made by the time World War II broke out. In September 1940 the National Defense Research Committee (NDRC) was being discussed by leaders of the scientific community as an important adjunct to the military in the event of U.S. involvement in the war. Early recognizing the importance and probable results of the war, Ewing obtained a leave of absence from Lehigh University and moved to the Woods Hole Oceanographic Institution (WHOI) to commence defense research. Without recompense, until the NDRC was officially formed in January 1941, he and his former students wrote Sound Transmission in Sea Water, the standard manual throughout the war and long after for understanding and predicting the results of sound-echo ranging. They also redesigned the bathythermograph from a bulky, tedious, and unreliable instrument to one capable of obtaining temperature-depth information to depths of 900 feet from ships underway at speeds up to 20 knots. It was adopted by the Navy and was the standard instrument with only minor changes for over 20 years.
During the war Ewing was the leading physicist at WHOI in the development and application of underwater photography and underwater sound for use by the Navy. It was in this period that he introduced the long-range sound transmission studies, resulting in the SOFAR system and providing the basic ideas behind the Navy's long-range surveillance and detection systems.
Lamont-Doherty Geological Observatory
In 1946 Ewing initiated an extensive program of geophysical training for graduate students at Columbia University. He was promoted to professor in 1947 and was made Higgins Professor of Geology in 1949. That year Columbia made available the former Thomas W. Lamont estate for the use of the geophysics group to undertake studies in earthquake seismology. The Lamont Geological Observatory was formed as a part of the department of geology with Ewing named director. In 1961 the observatory was changed to a research institute within the university to promote research with other university departments; in 1969 the name was changed to the Lamont-Doherty Geological Observatory.
From 1947 to his retirement Ewing continued his work at Columbia and WHOI. During his career, he carried out an extensive research career authoring or coauthoring 280 papers and three books. He received 10 honorary degrees from universities in four countries and 26 medals and awards from institutions and scientific societies of eight nations. He died at the age of 67 in 1974. His wife, Harriet, collected many of his private papers and donated them to the University of Texas. They are housed at the Harry Ransom Humanities Research Center in Austin.
Ewing's contributions to oceanography are discussed in Robert C. Cowen, Frontiers of the Sea: The Story of Oceanographic Exploration (1963); and Warren E. Yasso, Oceanography: A Study of Inner Space (1965). Additional material on Ewing is in David Robert Bates, ed., The Planet Earth (1957; rev. ed. 1964); William S. von Arx, An Introduction to Physical Oceanography (1962); and Günter Dietrich, General Oceanography: An Introduction (trans. 1963).
Further information on Ewing can be found in Frederic L. Holmes, ed., Dictionary of Scientific Biography, vol. 17 (1970; rev. ed. 1990), and Roy Porter, ed., The Biographical Dictionary of Scientists (1994). □