Erwin W. Mueller was the first man to see an atom, thanks to the specialized microscope he developed. He invented the field ion microscope in 1955 after a year of tinkering with the design.rnrn“It was a sticky day in August that I became the first person to see an atom,” he said of his research. “On that day, the regular array of atoms and a crystal lattice became clearly visible through the field ion microscope which I had developed.”rnrnYears earlier in 1950, he developed a field electron microscope which allowed him to produce images of extremely small molecules — some as small 1-25,000,000th of an inch in diameter.rnrnHe also invented another device — an atom probe — which could zero in on a single atom and allowed him to identify elements by atomic weight.rnrnBy Christine Ayala