Meanwhile, in 1859, Edwin drake (1819-1899) struck oil in Pennsylvania. Soon there was a flourishing oil industry in Pennsylvania. The first oil pipeline was built in 1865. In 1874 Levi Strauss began making riveted jeans. An increasing number of Americans lived in cities. By 1900 almost 1/3 of them did. by then there were more than 40 cities with a population of over 100000. (It wasn't until 1920 that the majority of Americans lived in cities). Conditions in the industry cities were often appalling. Many people lived in overcrowded slums. Meanwhile Americans agriculture continued to boom.
It was helped by new technology. Cyrus McCormick invented a mechanical reaper in 1834. John Deere (1804-1886) in vented the steel plow in 1838. In 1854 the first successful self-governing windmill (that changed direction automatically to face the wind) was made. In 1874 barbed wire was patented.