There he found the image pasted above. It’s of a funeral parade for Rear Admiral Winifred Scott Schley, taken on October 5, 1911. (Definitely follow the link to see a larger picture of the photo. It’s got incredible detail).
Schley was born in 1839 in Maryland. After serving in the Civil War he had a long career in various American Imperialist conflicts of the late 19th century, including the Spanish American War. After that war, he came to dispute a history of the war that described him as a “caitiff, poltroon and coward.” (GM had no idea what those first two words meant, but it turns out they are just fancier ways to say the word coward).
A committee of inquiry was formed yo determine the truth of the accusation. It did not find in his favor:
The majority report of the court found that Commodore Schley failed to proceed to Santiago with due despatch, that the squadron should not have been delayed by the yacht U.S.S. Eagle, that he should not have turned westward, that he should have obeyed the Navy Department’s order of May 25, 1898, that he did not do his utmost to capture the Colon, that the turn of the Brooklyn caused the Texas to stop, for carelessness in endangering Texas, for blanketing the fire of other American vessels, that he did injustice to Lieutenant Commander Hodgson (Navigation officer of the Brooklyn at the time of the incident), that his conduct in the Santiago campaign was characterized by vacillation, dilatoriness, and “lack of enterprise,” and that his coal reports were inaccurate and misleading. Admiral George Dewey, however, presented a minority report, in which he praised Schley for promptness and efficient service, and gave him the credit for the destruction of Cervera’s fleet.
Despite this poor character report, Schlay received full honors for his funeral. The Washington Evening Star reported that he was a “great sea fighter” and over a thousand members of naval organizations accompanied his casket from his home at 1826 I St., to St. John’s Church (the one on Lafayette Square), and onward to Arlington cemetery for burial. In accordance with his wishes, he received the “impressive masonic commitment rites at the grave”.
The shot capture by the postcard shows the procession as it makes its way down M St., presumably to cross the Aqueduct Bridge to Arlington. It would probably have made more sense to go across the Memorial Bridge, but it wasn’t built for another 21 years.