The First Industrial Revolution, which began in the 18th century, merged into the Second Industrial Revolution around 1850, when technological and economic progress gained momentum with the development of steam-powered ships, railways, and later in the 19th century with the internal combustion engine and electrical power generation. The period of time covered by the Industrial Revolution varies with different historians. Eric Hobsbawm held that it 'broke out' in Britain in the 1780s and was not fully felt until the 1830s or 1840s, while T. S. Ashton held that it occurred roughly between 1760 and 1830. Some twentieth century historians such as John Clapham and Nicholas Crafts have argued that the process of economic and social change took place gradually and the term revolution is not a true description of what took place. This is still a subject of debate amongst historians. GDP per capita was broadly stable before the Industrial Revolution and the emergence of the modern capitalist economy. The Industrial Revolution began an era of per-capita economic growth in capitalist economies. Historians agree that the Industrial Revolution was one of the most important events in history. The most significant inventions had their origins in the Western world, primarily Europe and the United States.