Oven gas stove included the AGA cooker invented in 1922 by Gustaf Dalén. The first electric ovens were invented in the very late 19th century, however, like many electrical inventions destined for commercial use, mass ownership of electrical ovens could not be a reality until better and more efficient use of electricity was available. More recently, ovens have become slightly more high-tech in terms of cooking strategy. The microwave as a cooking tool was discovered by Percy Spencer in 1946, and with the help from engineers, the microwave oven was patented. The microwave oven uses microwave radiation to excite the molecules
Herbert Spencer this period were expressed in what has become his most famous work, "The Man Versus the State". The exception to Spencer's growing conservativism was that he remained throughout his life an ardent opponent of imperialism and militarism. His critique of the Boer War was especially scathing, and it contributed to his declining popularity in Britain. Spencer also invented a precursor to the modern paper clip, though it looked more like a modern cotter pin. This "binding-pin" was distributed by Ackermann & Company. Spencer shows drawings of the pin in Appendix I (following Appendix H) of his autobiography along with published