Tasimeter

The tasimeter, or microtasimeter, or measurer of infinitesimal pressure, is a device designed by Thomas Edison to measure infrared radiation. In 1878, Samuel Langley, Henry Draper, and other American scientists needed a highly sensitive instrument that could be used to measure minute temperature changes in heat emitted from the Sun's corona during the July 29 solar eclipse, due to occur along the Rocky Mountains. To satisfy those needs Edison devised a microtasimeter employing a carbon button.^[1]