Final answer:
The success of a song in the late 1800s was measured by sheet music sales, as this was pre-radio and streaming technology. Patriotic themes were common during this era, influenced by events like the Spanish-American War, and the expanding middle class also affected the music industry.
Step-by-step explanation:
During the late 1800s, the success of a song was determined by sheet music sales. Before the advent of modern music technology like streaming services and radio, people would purchase sheet music to play at home, often on pianos. Looking at the popular songs from 1898, one can observe trends such as patriotism and the influence of events like the Spanish-American War. Additionally, the rise of the middle class influenced music trends by expanding the audience size, leading to a shift from the patronage system for classical composers to public concerts and festivals that catered to broader, paying audiences.