When Solomon G. Brown joined the Smithsonian staff in 1852, the institution had existed for only six years. The Castle wouldn't be completed until 1855. What would become the Mall was near a sewage canal and in Brown's time would be a railroad bed, as well as a garden.

Brown saw all this growth and change through a unique perspective. He was the first African American employee at the Smithsonian and worked there for 54 years. Though Washington had a sizable number of freed blacks, most of Brown's contemporaries were still slaves in 1852. And few had steady jobs at an institution that already had an international reputation.

Hired in his early twenties, Brown started out as a laborer, building exhibition cases and preparing maps. He became a skilled clerk. He was comfortable around the bustling science work, the principal focus of the Smithsonian of that time, and educated himself about natural history. Eventually Brown was invited to speak to scientific societies in the region and prepared the diagrams for his own talks, as well as for the Smithsonian scientists. The Smithsonian, however, was only one part of his life, and his activism in local politics and church organizations and his enormous output of poetry made him one of the city's best-known black men in the 19th century.

One of the events he witnessed was the groundbreaking for the Natural History Museum on June 15, 1904. Yesterday, leaders and employees of the museum, descendants of Brown and local historians remembered him. They planted a cedar of Lebanon, a species that was removed during the building's construction, in his honor. They dedicated a plaque with a photo of Brown from 1891.

Calling Brown "a remarkable man," Cristian Samper, director of the museum, said the employee was aware of the history of the day but also lamented the destruction of the natural vistas on the Mall. "Mr. Brown was concerned that when construction began, a number of old and majestic trees, including towering cedars, mulberries and flowering cherry trees, would have to be taken down."

When he reached his 50th anniversary at the Smithsonian, Brown wrote a poem, which was read by Gail Lowe, a historian with the Anacostia Museum and Center for African American History and Culture. In it, Brown notes that the precursors to the Weather Bureau and the Fish Commission were started during his tenure at the Smithsonian. So was the National Zoo, which he referred to in his poem. "He also gained that splendid park / a place once dangerous, wet, and dark / is now a splendid country," it reads.

He retired in 1906 and died the same year.

His name has been closely associated with the history of Washington's black community, most visibly in Anacostia. He was born free around 1829, near what is now 14th and U streets NW, one of six children of Isaac and Rachel Brown. Solomon didn't attend school but helped support his family after his father's early death. He worked at the post office and then as an assistant to Samuel F.B. Morse, inventor of the telegraph, and the Smithsonian's Joseph Henry, who worked to establish the first magnetic telegraph system between Washington and Baltimore.

In an account Brown gave of his life, he said he carried the first telegraph message to the White House.

In Anacostia, he petitioned the Freedman's Bureau, the agency overlooking the welfare of blacks after the Civil War, to establish a tract for homesteading for blacks. That became known as Barry's Farm. He joined other leaders in petitioning for the Emancipation Memorial Monument in Lincoln Park. Brown was also a trustee of the 15th Street Presbyterian Church and was elected to the city's House of Delegates for three consecutive one-year terms.

Clara Ellis Payne, a retired university administrator and cousin of Brown from New York, helped turn over the soil around the tree yesterday and was immediately surrounded by people who wanted her autograph. Family lore, she said, describes Brown as a confident and content man. "He was gentle, he was happy he was a free man. He always did everything he could to uplift people."

Solomon G. Brown, shown in an 1891 photo, retired from the Smithsonian in 1906 and died the same year.