A worksheet function that is called by Excel can call back into Excel using the C API. An XLL command that is called by Excel can call the C API. DLL and XLL functions and commands that are called by VBA when VBA has itself been called by Excel can call the C API.
Cell Theory. The discovery of the cell was made possible by the invention of the microscope, which was made possible by improved lens-grinding techniques.Antoni van Leeuwenhoek (1632-1723), a Dutch tradesman, learned to grind lenses and assemble them into simple microscopes.nspired by Hooke's work, Leeuwenhoek began making microscopic examinations of his own. In 1678, he reported to the Royal Society that he had discovered little animals -- bacteria and protozoa -- in various samples. The society asked Hooke to confirm Leeuwenhoek's findings, and he did.
Thomas Edison was born in 1847 in Milan, Ohio. Like Ben Franklin, he was both a scientist and an inventor. In fact, Edison patented 1,093 inventions in his lifetime including the kinetoscope, the phonograph, and his most famous - the incandescent light bulb. The Menlo Laboratory in Newark, New Jersey, was to become the first research and development lab in the world. Edison called this lab his invention factory.. In 1879, after 1,200 experiments, Edison made a light bulb using carbonized filaments from cotton that burned for two days.