to contribute $25,000 as well. Edison did the majority of the research and planting, sending results and sample rubber residues to his West Orange Lab. Edison employed a two-part Acid-base extraction, to derive latex from the plant material after it was dried and crushed to a powder. After testing 17,000 plant samples, he eventually found an adequate source in the Goldenrod plant. Edison decided on Solidago leavenworthii, also known as Leavenworth's Goldenrod. The plant, which normally grows roughly 3–4 feet tall with a 5% latex yield, was adapted by Edison through cross-breeding to produce plants twice the size and with a latex yield of 12%. During the 1911 New York Electrical show, Edison told representatives of the copper industry it was a shame he didn't have a "chunk of it". The representatives decided to give a cubic foot of solid copper weighing 486 pounds with their gratitude inscribed on it in appreciation for his part in the "continuous stimulation in the copper industry". Other inventions and projects Fluoroscopy Edison is credited with designing and producing the first commercially available fluoroscope, a machine that uses X-rays to take radiographs. Until Edison discovered that calcium tungstate fluoroscopy screens produced brighter images than the barium platinocyanide screens originally used by Wilhelm Röntgen, the technology was capable of producing only very faint images. The fundamental design of Edison's fluoroscope is still in use today, although Edison abandoned the project after nearly losing his own eyesight and seriously injuring his assistant, Clarence Dally. Dally made himself an enthusiastic human guinea pig for the fluoroscopy project and was exposed to a poisonous dose of radiation; he later died (at the age of 39) of injuries related to the exposure, mediastinal cancer. In 1903, a shaken Edison said: "Don't talk to me about X-rays, I am afraid of them." Nonetheless, his work was important in the development of a technology still used today. Tasimeter Edison invented a highly sensitive device, that he named the tasimeter, which measured infrared radiation. His impetus for its creation was the desire to measure the heat from the solar corona during the total Solar eclipse of July 29, 1878. The device was not patented since Edison could find no practical mass-market application for it. Telegraph improvements The key to Edison's initial reputation and success was his work in the field of telegraphy. With knowledge gained from years of working as a telegraph