Who invented Electrocardiograph(EKG)? 

Cotton Gin was invented by Eli Whitney in 1793, which is used to separate cotton seeds from cotton fiber.

Hence, it was an important invention because it dramatically reduced the amount of time it took to separate cotton seeds from cotton fiber.

Robert Brown, Scottish botanist, Discovered The Nucleus of a Cell in 1831, London. When Brown was studying orchids under microscope when he observed an opaque area, which he called the "Areola" or "Nucleus", in the cells of the flower's outer layer.

The nucleus was also described by Franz Bauer in 1804 but in detail Robert Brown made it in 1831.

Michael Faraday invented Electric Generator in 1831.

• The operating principle of electromagnetic generators was discovered in the years of 1831–1832 by Michael Faraday.

• The principle later called Faraday's law, is that an electromotive force is generated in an electrical conductor which encircles a varying magnetic flux.

Alfred Bernhard Nobel was a Swedish chemist, engineer, inventor, businessman, and philanthropist. Known for inventing Dynamite, Nobel also owned Bofors, which he had redirected from its previous role as primarily an iron and steel producer to a major manufacturer of cannon and other armaments.