Although Fajans and Göhring had been the first to discover the element, custom required that an element was represented by its longest-lived and most abundant isotope, and brevium did not seem appropriate. Fajans agreed to Meitner naming the element "protoactinium" (subsequently shortened to protactinium), and assigning it the chemical symbol Pa. In June 1918, Soddy and John Cranston announced that they had independently extracted a sample of the isotope, but unlike Meitner they were unable to describe its characteristics. They acknowledged Meitner's priority, and agreed to the name. The connection to uranium remained a mystery, as neither of the two known isotopes of uranium (uranium-234 and uranium-238) decayed into protactinium. It remained unsolved until uranium-235 was discovered by Arthur Jeffrey Dempster in 1935.