[2] Purchased by the Navy from the Brazilian Government on 11 July 1898, she was renamed Buffalo, commissioned in ordinary a week later, fitted out as an auxiliary cruiser at New York Navy Yard; and placed in full commission on 22 September 1898, with Lieutenant Commander Joseph Newton Hemphill in command.

In 1916, she again served in Mexican waters, and between May and August 1917, Buffalo transported the Special Diplomatic Mission of the United States to Russia.

Conversion was completed in June 1918, and after loading torpedo equipment at Newport, Rhode Island, she departed for Brest, France, via Bermuda.

From February until September 1919 she had similar duty with the Azores Detachment at Ponta Delgada and then returned to New York.

On 31 December 1919, Buffalo arrived at San Diego, California to commence her duties as repair ship and tender to Destroyer Squadrons 5 and 11, Pacific Fleet.