In the early 19th century after the expiration of Watt's patent , the steam engine underwent great increases in power due to the use of higher pressure steam which Watt had always avoided because of the danger of exploding boilers, which were in a very primitive state of development.
Due to the ever-increasing power demands of the 1800s, especially in manufacturing, innovations were made to existing steam engines and a number of entirely new steam engines were developed.