Holmium atomic weight

Cleve s fame rests chiefly, however, on his discoveries among the rare earths. After obtaining some erbia from which all the ytterbia and scandia had been removed, and after noticing that the atomic weight of the erbium was not constant, he succeeded in resolving the earth into three constituents erbia, holmia, and thulia (21). The absorption bands of holmium had already been noticed by the Swiss chemists M. Delafontaine... 

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