on of electrons, that would make a new element. Trials by Fermi and his co-workers with various elements led to unmistakeable evidence of the expulsion of electrons (beta activity) with at least four different rates of decay (half-lives). Claims were advanced for the creation of elements 93 and 94 and possibly further (the transuranium elements, Table I). Much difficulty was experienced, however, in proving that the activity really was due to the formation of elements 93 and 94. As more people became interested and extended the scope of the experiments, the picture became more confused rather than clarified. Careful studies soon showed that the activities did not decay logarithmically--which means that they were caused by mixtures, not individual pure substances--and the original four activities reported by Fermi grew to at least nine.
As a matter of fact, the way out of the difficulty had been indicated soon after Fermi's original announcement. Dr. Ida Noddack pointed out that no one