Astronomy on the Flats: How the Moons of Mars and the Death of a President Altered the Late Nineteenth-Century Washington, DC, Landscape

Editor’s note: This post is part of our theme for March 2023, Science City, an exploration of the ways cities and science have interacted over time and around the world.

By Vincent Femia

Simon Newcomb often arose from his bed in the middle of the night to walk two miles to the Naval Observatory grounds. In the 1860s, the young astronomer lived east of 13th Street NW and north of the White House.[1] His walk cut west, just north of the elegant homes on Lafayette Square, and through Washington Circle before arriving at the Observatory. While the large, domed building sat secluded on the banks of the Potomac harbor, its environment left much to be desired. One of the city’s main sewers fed into the marshlands of the Potomac flats, where malaria and the stench of the river hung in the air. River fog shrouded the Observatory during certain months, preventing observation, and the growing city after the Civil War only added insult to injury. Observatory workers feared the miasmas—a belief in the danger of unsanitary air and smells—of the flats and the environment’s threats to their scientific work. They considered sleeping on or near the Observatory grounds hazardous, so most of them lived a mile or more away. But if the clouds cleared out after a hazy evening, Newcomb would take a few hours of sleep at home and then return to the Observatory to continue his work.

During the 1860s, wartime construction populated the Observatory’s undeveloped neighborhood. Walking from his home east of the Observatory, Newcomb passed the storehouses of the Quartermaster and Subsistence Departments, which occupied the southwestern part of the city. A heavy rain transformed these streets into canals. The mud, worn down by iron wheels, created swamps that thickened with the sun’s heat, returning to liquid with the next summer storm. At night, as Newcomb eagerly marched his way back to the Observatory grounds, rats, engorged on an ample storehouse food supply, competed for the right of way in the mud-filled streets.[2]

The astronomers and aides had proposed relocating the Naval Observatory for decades before relocation finally happened in 1893, and the District’s Board of Health had advocated for the reclamation of the Potomac flats in the early 1870s.[3] But it was not until 1877, after Naval Observatory astronomer Asaph Hall discovered the moons of Mars, that debate truly ensued over the location of the Observatory, the health of the environment, and the sad state of the southwestern part of the city. The tale of the Naval Observatory in late nineteenth-century Washington reveals the interconnectedness of science, city, and environment. In our story, this relationship blends the built environment with the natural environment, city planning, and disease geographies. Simply put, science and city development became interlocking parts in a larger story about urban modernity in the nascent capital city.[4]

U.S. Naval Observatory, Washington, DC, (ca. 1880-90), Prints and Photographs Division, Library of Congress.

A standard and intuitive narrative about the history of astronomy tells us that the urban observatory’s importance faded with the growth of major cities. Light and air pollution, noise, and vibrations of a bustling metropolis no longer made novel scientific work tenable in the city, so astronomers packed up their instruments and headed west, climbing in elevation up hillsides and mountains.[5] Yet, this narrative fails to capture the complexity of decisions, interests, and built/natural environmental factors at play in determining how a scientific institution, such as the Naval Observatory in Washington, would fit into a city’s urban landscape, both culturally and physically. Planning the future of the Naval Observatory was not just about science. For astronomers, city developers, and congressmen alike, the Observatory’s future remained bound to real estate and commercial interests, city planning, environmental change in the landscape, city identities, and the capital city’s pursuit of urban modernity.

Urban historians have also rarely looked at scientific institutions and buildings as distinct features of the urban built environment. What do these structures represent in a cityscape? How do they relate to other structures in the built environment? And how does the practice of science within these institutions shape the way that the built environment is viewed and altered? For city boosters who longed to bring capital, commerce, and bourgeois beauty to Washington, a certain shade of urban modernity, laced with class- and race-based assumptions, filled the blueprints. How, then, did science fit into Washington’s future?


Asaph Hall discovered the moons of Mars in August of 1877 using the largest telescope in the world. As Newcomb and Hall spoke with reporters about the twenty-six-inch refractor and the discovery at the Observatory, the press focused on more than just the terrains and sizes of Phobos and Deimos. Reporters noted the malarial cesspool of the Potomac flats that festered and stank in the sweltering summer heat, especially during low tide. Just months after Hall reported his discovery in August, articles pointed to the “shroud” of malaria that hung over the river, forcing the “lives of priceless value to science” to “[drink] in the subtle malaria, and [die] slowly.”[6] “Malaria Killing the Observers,” The Washington Post wrote in December of 1877.[7] Newcomb, in fact, had long struggled with bouts of the disease, which eventually weakened him considerably by the end of the 1870s.[8] Recalling his early days at the Observatory, Newcomb wrote that “it was not considered safe to take even an hour’s sleep at the observatory” given that it was located “in one of the most unhealthy parts of the city.”[9]

In the wake of Hall’s discovery, Washington astronomers took active steps toward ameliorating the Observatory’s environmental conditions. In September, John Rodgers, the new superintendent of the Naval Observatory, drafted a report for Congress on the Observatory’s relocation, collecting the opinions of respected medical doctors and astronomers from the Washington area. Rodgers’s opening paragraph made his case clear: “I found, upon taking charge of the Observatory, that the malarious influences surrounding it were notorious, and that from May to about the middle of October the officers whose services were necessarily in the observatory at night, paid the penalty in impaired health and in diminished efficiency. The fogs which arise from the river, driven by the prevailing winds, float above the instruments and lessen their usefulness.”[10] The Potomac flats were both dangerous to health and dangerous to science, Rodgers told Congress. Many attributed the early death of James Melville Gilliss, superintendent of the observatory from 1861 to 1865, to the unhealthy environment. Many others argued that the flats exacerbated their preexisting medical conditions.[11] Both the science and men who worked at the Observatory would suffer as long as city improvements did not touch the harbor between Georgetown and Washington. And the time was ripe for suggesting such large-scale improvements to the city.

The 1870s marked Washington’s most dramatic urban development projects to date. In 1871, Alexander Shepherd, vice-chair of the Board of Public Works and later governor of the District, began excessively expensive and perhaps overly ambitious development projects that completely remodeled DC’s landscape. City leaders, developers, and boosters longed to propel this fledgling capital into aesthetic and infrastructural modernity—a capital city fit for the nation. But this modernity had little care for democracy, especially Black suffrage in Washington. The territorial government had already restricted most of DC’s residents’ voting rights. But in 1874, the institution of a commission government completed the process of full disenfranchisement. Urban modernity in Washington followed the whims of those in charge, racked up an outlandish debt, and dabbled in corruption. Congress ousted Shepherd in 1874 for this financial mismanagement, and DC’s new commission government continued development projects along more financially conservative lines.

“Modern science” and “modern conveniences,” the New York Times reported on D.C.’s improvements, followed the “spirit of progress” that had advanced upon the city.[12] The development and public relations campaign born out of the 1870s remodeled public parks, paved streets, planted trees, erected stately row homes, and reinvented the city’s sewer system.[13] Visions of urban modernity etched themselves into the new landscape, but also into the industry of the city—the large-scale technical organization, quantification, and mobilization of knowledge essential to modern governance and bureaucracy became a celebrated quality of the city, with science at its helm. The generation and dissemination of knowledge was the work of government, whether by printing the works of the various bureaucratic and scientific agencies at the Government Printing Office, or using the “most powerful telescope ever made” at the Naval Observatory.[14]

Important federal buildings surround a pastoral image of the countryside in and around Washington. The Naval Observatory can be seen to the right of the central image. Frontpiece, The National Capital Explained and Illustrated: A Convenient Guide to All Points of Interest in the City of Washington (Washington, D.C.: Devlin & Company, 1871).

Yet, the Observatory grounds posed a problem. The Naval Observatory, like its other scientific companions in Washington, figured prominently in pictorial representations of the city as well as guidebooks for visitors. It sat upon government reservation no. 4, and was thus open to the public within certain hours. Like the Smithsonian Institution, the Observatory’s influence reached far and wide, sending telegraphic time signals across the nation so that cities could appropriately adjust their clocks. The Observatory building itself, however, had become rundown and dilapidated. The superintendent’s residence sat at the far-left wing, and a pavilion for the 8.5-inch transit circle sat at the far-right wing. The central portion of the Observatory housed the 9.6-inch refractor telescope, with the time ball and mast atop the central dome. A new dome on the south side was built in 1873 to house the 26-inch refractor.[15] The wear and tear of years of work and the erosion from a harsh environment demanded nearly $30,000 dollars in repairs, superintendent Rodgers argued. The far-right pavilion had become storage, making the transit circle unusable, and the library could not hold new records of observations and calculations. With the menace of the Potomac flats, the area around the Observatory had been valued at less than fifty cents per square foot, far less than the land further removed from the river.[16]

Asaph Hall’s discovery brought new attention from the press, the public, and Congress. Modern science and a modern capital needed to coalesce, the astronomers argued, and this could only happen through dramatic environmental, architectural, and real estate changes. The astronomers appealed, in fact, to ideas that first emerged from an 1872 Board of Survey, appointed by Congress, for the improvement of the harbor of Washington and Georgetown. Leveling Observatory Hill, the Board recommended, and distributing the land to reclaim the Potomac flats would be essential to the city’s improvement and commerce.[17] In Rodgers’s September 1877 report, government engineer Montgomery Meigs made the same recommendations. Removal of the Observatory and reclamation of the flats would “increase the area of the city and improve its health. It would be a paying improvement, whether the land redeemed was laid out and sold for building purposes or planted and used as a park.”[18] Reclaiming the land and selling it for a profit to developers could fund the removal of the Observatory while simultaneously boosting commercial futures for the city. “The scheme of city improvements,” Simon Newcomb wrote, “contemplates making the region around the Observatory one of great commercial activity, and contemplates the building of a railroad around the foot of the hill on which the buildings are situated. The execution of this project would be incompatible with the continued efficiency of astronomical work in the present location.”[19]

Congress decided to act. In 1878, Congress introduced a bill on the reclamation of the Potomac flats and appointed a commission to ascertain the cost and advantages of relocating the Naval Observatory.[20] Its purpose was to find a spot that offered “healthfulness, clearness of atmosphere, [and] convenience of access from the city of Washington” as well as clean water, removal from the hot air and smoke of the city and from the disturbance of railways and roads.[21] Congress promised to lift the Observatory from the “fog and fever” of the river that gave only malaria and mist. The astronomers wished to move the Observatory north and up in elevation. Relocation to what used to be Washington County would provide relief from the Potomac fog, the unsanitary conditions of the river, and various hinderances from downtown. But they did not want to leave the city. “Convenience of access from the city of Washington” remained central to the Observatory’s function.[22]

Reclamation of the Potomac flats languished, however. So, too, did the new Naval Observatory. From 1880 to 1881, Congress delayed a vote on the bill while newspapers published numerous stories on political indecision and festering waters at the southern part of the city. The Smithsonian invited sanitary engineer and civic reformer George E. Waring Jr. to give a lecture on the sanitary drainage of the city. “There is no doubt,” he claimed, “that the Potomac flats might be rendered healthful and valuable by being filled…with fresh upland earth.”[23] In 1881, the Post spoke with several Washington doctors to gauge the severity of malaria in the capital. While many of the doctors consulted in the article agreed that, perhaps, the dangers of malaria in the city were not as severe as they often were made out to be, certain preventative measures could be taken. One included covering up the flats on the Potomac River. “That they breed miasma,” a Dr. Hagard stated, “is shown from the very unhealthy condition of those who are forced to reside on the observatory grounds.”[24]

Smithsonian grounds during the great flood, February 12, 1881. Ranald Douglas, photographer, Prints and Photographs Division, Library of Congress.

Scientists in Washington had taken on the politics of urban development precisely because the city’s built and natural environments were so central to scientific practice. The Naval Observatory astronomers confronted a multitude of considerations: excessive fog that made observation difficult, disease hovering about the Potomac flats, the growth of Washington that threatened precise measurements and observation, the city’s ambitions as the nation’s capital, Congress’s agenda of spending, and provisions for real estate acquisitions for the Observatory’s relocation. But by the late 1870s, the growth of Washington could now be used to their advantage. Frequent flooding of the Mall from the late 1870s to the early 1880s made the Potomac flats issue more pressing. It was time, the astronomers argued, to fill in the flats, relieve the Observatory from its dangerous environment, and to replace the unbecoming, rundown facilities of this national scientific establishment. These arguments continued into the 1880s, even as work on the Potomac flats began. The 1885 National Academy of Sciences report reiterated what had been said a decade ago, that the “present site of the Observatory will be needed for projected city improvements,” and that “every consideration, sanitary, scientific, and economical, requires that the present site and the present structure should be abandoned.”[25]

When Charles Guiteau shot president James Garfield in 1881 at the Baltimore and Potomac Railroad Station on the National Mall just months after the inauguration, the world of Washington science jumped to aid the ailing president. The commotion at the train station spread through the city “faster than a messenger could carry the news,” and reached Simon Newcomb just as he was entering his office.[26] Newcomb, along with Alexander Graham Bell, John Wesley Powell, and others, worked diligently to ease the president’s suffering. Garfield had become a trusted friend of science as an Ohio congressman. He was also a longtime friend of Newcomb, first meeting the young astronomer at a Washington boardinghouse in 1862. As Garfield lay bedridden in July after Guiteau’s assassination attempt, four people attending to Garfield were “seized with malaria.”[27] “While President Garfield lay wounded in the White House,” the Evening Star wrote after his death, “the question of the malarial influences of the Potomac flats was so generally discussed by the press of the land, that the people in the length and breadth of the country now know of the existence of the nuisance.”[28]

In his final moments, Garfield had put a spotlight on the astronomers’ malarial woes. And this odd set of circumstances coincidentally had almost poetic resonance with Garfield’s love of science in Washington. Garfield had helped the meteorological division of the Signal Service get off its feet, became a Regent of the Smithsonian, and, as chairman of the Committee on the Census of 1870, demanded that “statistical science is indispensable to modern statesmanship.”[29] He had attended meetings of the Literary Society of Washington to hear Joseph Henry lecture on physics and dined with Simon Newcomb to discuss “parallax and beefsteak” over supper.[30] In a morbid turn of events, Garfield’s death was his final contribution to Washington science and to the city. Just months after his death, Congress finally directed the Army Corps of Engineers to dredge the river. With gradual appropriations, the work of filling in the flats continued until 1890. The Navy purchased a new site for the Observatory in 1881. Congress appropriated funds for the new facilities from 1886 to 1891, and the astronomers finally began work at the new Observatory in 1893.[31]

Washington, DC, in 1850. The Potomac cuts in toward the White House. The Naval Observatory is along the Potomac, directly west of the White House. “Map of the City of Washington D.C.,” Geography and Maps Division, Library of Congress.
Washington, DC, in 1873. “Map of the District of Columbia,” Geography and Maps Division, Library of Congress.
Washington, DC, in 1884. By the middle of the 1880s, work on the Potomac flats had begun. This map shows the proposed development and reclamation. “Guide Map of Washington,” Geography and Maps Division, Library of Congress.
Washington, DC, circa 1910. Potomac Park is completed. The Naval Observatory has been moved north. “Map of Washington, D.C.” Geography and Maps Division, Library of Congress.

Vincent L. Femia is a PhD candidate in the history of science at Princeton University. His work focuses on histories of science and the American city at the turn of the twentieth century. Before beginning his PhD at Princeton, Vincent completed an MPhil in the history and philosophy of science at the University of Cambridge.

Featured image (at top): The pathway leading to the Naval Observatory, photographed between 1861 and 1865, Prints and Photographs Division, Library of Congress.


[1] Newcomb’s addresses taken from William H. Boyd, Boyd’s Washington and Georgetown Directory (Washington, DC: William H. Boyd, 1864); William H. Boyd, Boyd’s Directory of Washington and Georgetown, Together with a Compendium of Their Government Institutions and Trades (Washington, DC: William H. Boyd, 1868); William H. Boyd, Boyd’s Directory of Washington, Georgetown, and Alexandria, Together with a Compendium of Their Government Institutions and Trades (Washington, DC: William H. Boyd, 1870).

[2] Simon Newcomb, The Reminiscences of An Astronomer (New York: Houghton, Mifflin and Company, 1903), 224, 334-335.

[3] Constance McLaughlin Green, Washington: A History of the Capital, Vol. 1 (Princeton: Princeton University Press, 1961), 365-367; Steven J. Dick, Sky and Ocean Joined: The U.S. Naval Observatory 1830-2000 (Cambridge: Cambridge University Press, 2003), 296.

[4] For a discussion of the relationship between the built and natural environments, how they are intertwined, and how historians have historically erected a barrier between the two, see Martin V. Melosi, “Humans, Cities, and Nature: How Do Cities Fit in the Material World?” Journal of Urban History 36, no.1 (2010): 3-21.

[5] David Aubin, “The Fading Star of the Paris Observatory in the Nineteenth Century: Astronomers’ Urban Culture of Circulation and Observation,” Osiris 18 (2003): 79-100. Aubin examines the Paris Observatory, which remains in the city. “But around [the old observatory building],” he writes, “modern buildings accommodate dozens of astronomers, who still manage to work efficiently in the very spot from which, more than a century ago, urban development threatened to expel them. Meanwhile, vibration, noise, and light pollution have hardly abated. Surely something—other than pleasant Sunday walks—must keep astronomers in Paris,” 80. How the observatory was “woven into the social, political, and economic fabric of the city” made its removal difficult, Aubin contends. For geographic movement of American astronomy at the turn of the twentieth century, see Joshua Nall, News from Mars: Mass Media and the Forging of a New Astronomy, 1860-1910 (Pittsburgh: University of Pittsburgh Press, 2019).  

[6] Lucy E. Sanford, “Washington Naval Observatory,” New York Observer and Chronicle, Dec.20, 1877.

[7] “The Malaria Killing the Observers,” Washington Post, Dec. 15, 1877.

[8] Albert E. Moyer writes: “while physically strong, he suffered from an infirmity traceable to his first years in Washington when he started working at the Naval Observatory with its swampy, mosquito-infested setting; he began to experience ‘a bilious or malarial attack’ once or twice a year. Usually the episodes lasted only a week or two, but one ‘bilio-malarial fever’ that struck in his early thirties persisted for several weeks and left him weak for months. Though the attacks tapered off beginning in the 1870s, they weakened his legs so much that, try as hard as he might, he could no longer walk beyond eight or ten miles.” Albert E. Moyer, A Scientist’s Voice in American Culture: Simon Newcomb and the Rhetoric of Scientific Method (Berkeley: University of California Press, 1992), 67. Newcomb, for example, began a letter to American paleontologist Othniel Charles Marsh on September 25, 1878 with “yours of the 21st reaches me at the end of a weeks sickness which I have employed in working off the September malaria.” Simon Newcomb to Othniel Charles Marsh, Sept. 25, 1878, Box 4, Simon Newcomb Papers, Manuscript Division, Library of Congress, Washington, DC.

[9] Newcomb, The Reminiscences of an Astronomer, 110.

[10] John Rodgers, Reports on the Removal of the United States Naval Observatory (Washington, DC: Government Printing Office, 1877), 3.

[11] Report of the National Academy of Sciences for The Year 1885 (Washington, DC: Government Printing Office, 1886), 43.

[12] “City of Washington: A Spirit of Progress and Improvement Developed,” New York Times, Dec. 12, 1871.

[13] For work on this tumultuous decade of politics and building in Washington, see Alan Lessoff, The Nation and Its City: Politics, Corruption, and Progress in Washington, D.C., 1861-1902 (Baltimore: The Johns Hopkins University Press, 1994) and Howard Gillette Jr., Between Justice & Beauty: Race, Planning, and the Failure of Urban Policy in Washington, D.C. (Philadelphia: University of Pennsylvania Press, 1995). For work on how Black voting and responses to Black voting shaped the city’s development and politics in the 1860s and 1870s, see Kate Masur, An Example for All the Land: Emancipation and the Struggle Over Equality in Washington, D.C. (Chapel Hill: The University of North Carolina Press, 2010) and Chris Myers Asch and George Derek Musgrove, Chocolate City: A History of Race and Democracy in the Nation’s Capital (Chapel Hill: The University of North Carolina Press, 2017).  

[14] Roose’s Companion and Guide to Washington and Vicinity (Washington, DC: Gibson Brothers, Printers, 1876). In 1999, Carl Abbott posed the question, “when and how did the ‘federal city’ become a ‘national city,’ and how have its national roles competed with those of other cities?” A complex web of city politics, bureaucratic growth, city development, and federal science produced this transition. In the 1870s, alongside the changing political regimes of the city, debates over what the “national city” was and ought to be filled the press and the halls of Congress. Carl Abbott, Political Terrain: Washington, D.C., from Tidewater Town to Global Metropolis (Chapel Hill: The University of North Carolina Press, 1999), 5.

[15] Dick, Sky and Ocean Joined, 172.

[16] City of Washington Statistical Maps, Compiled by Lieut. F. V. Greene, No. 1, Valuation of Real Estate Property, Library of Congress, Geography and Map Division, Washington, DC, https://www.loc.gov/resource/g3851fm.gct00015/?sp=2. Rodgers, Reports on the Removal of the United States Naval Observatory, 8.

[17] Dick, Sky and Ocean Joined, 296.

[18] Rodgers, Reports on the Removal of the United States Naval Observatory, 11-12.

[19] Rodgers, Reports on the Removal of the United States Naval Observatory, 8.

[20] “Reclamation of the Potomac Flats,” Evening Star, Apr. 22, 1878.

[21] Report of The Commission On Site For Naval Observatory (Washington, DC: Government Printing Office, 1879), 3-4.

[22] “Washington,” Detroit Free Press, Apr. 14, 1878.

[23] George E. Waring Jr., “The Toner Lectures. Lecture VIII. Suggestions for the Sanitary Drainage of Washington City,” in Smithsonian Miscellaneous Collections, Vol. XXVI (Washington, DC: Smithsonian Institution, 1883), 5.

[24] “Is Malaria a Myth?” Washington Post, Nov. 9, 1881.

[25] Report of the National Academy of Sciences for The Year 1885 (Washington, DC: Government Printing Office, 1886), 42, 44.

[26] Newcomb, The Reminisces of An Astronomer, 356.

[27] “The Potomac Flats,” Evening Star, July 25, 1881 and “The Suffering President,” Evening Star, July 26, 1881.

[28] “District Business Before Congress. The Reclamation of the Potomac Flats,” Evening Star, Nov. 23, 1881.

[29] A Tribute of Respect from The Literary Society of Washington to its Late President James Abram Garfield: Proceedings of a Meeting of the Society Held November 19, 1881 (Washington: 1882), Box 14, Literary Society of Washington Records, Manuscript Division, Library of Congress, Washington, DC.

[30] James Garfield to Simon Newcomb, Apr. 3, 1872, Box 22, Simon Newcomb Papers.

[31] “Improvement of Potomac Flats, Washington,” Scientific American, Sept. 19, 1891, 180. Dick, Sky and Ocean Joined, 299.

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