Some of the new technological inventions included the use of new basic materials, most importantly iron and steel, new energy sources which included both fuels and motive power, like coal, the steam engine and electricity. The invention of new machines like the cotton gin allowed increased production while at the same time reducing labor. The factory and mill system lead to important developments in transportation and communication, including the steamboat and telegraph. These technological changes made it possible to expand our use of natural resources and lead to the mass production of manufactured goods.