The Spanish-American War in 1898 was right at the edge where merchant steamers might be purchased for service as cruisers. One of the last examples where this occurred was the American cruiser Topeka.
The Topeka had been launched by Howaldt at Kiel in 1881. The ship had been built for Peru as the Diogenes, so perhaps the intent was to be a cruiser from the beginning. Peru did not take delivery and the Thames Iron Works acquired her. She sat idle until the Sino-Japanese War when the Japanese almost bought her. The deal did not go through, so she sat longer until the Americans bouth her for service in the war with Spain. Her original commander, Lieutenant Knapp, described her as a good seaboat. He felt very uncomfortable, though, in the newly purchased ship, as she was unarmed. The sponsons were plated in, probably as a preservation measure when the ship sat, laid up. She looked very much the "tramp steamer", as the New York Times reporter characterized her. She was very sad-looking and needed attention, including a new paint job.
The original American armament consisted of 8-4in/40, 2-57mm (6pdr), 4-47mm (3pdr), and 2-1pdr guns. The dimensions were something like 250ft x 35ft x 17ft-9in, so the ship was very cruiser-like in appearance, size, and armament. The ship was unarmoured, however. The maximum speed was 16 knots, but that was fairly compatible with the older and smaller American cruisers and gunboats. The nominal displacement was 2,372 tons.
The Topeka was only finally sold for scrap in 1930, after being periodically commissioned and decommissioned. Her latter career had been spent mostly as a training ship.