A SCIEXTIFIC CAREER 23 



to crystallize these compounds, we would not have been able to separate 

 hafnium from zirconium. All hafnium commercially available for the 

 next twenty-five years was prepared by crystallizing the double- fluorides. 



V. M. Goldschmidt 



Auer von Welsbach presented me with small samples of octohydro- 

 sulphates of all elements of the rare-earth group. This gift enabled me to 

 measure the density of these compounds and to observe a systematic 

 decrease of the size of the ions of rare-earth elements when proceeding 

 from cerium to lutetium, a contraction which explained the extreme 

 kinship of zirconium and hafnium, which are more closely related chemi- 

 cally than any other elements of the periodic system. (When testing the 

 rare earths for radioactivity, making use of Auer von Welsbach's samples, 

 we discovered that samarium emitted a-rays.) In Oslo, V. M. Gold- 

 schmidt simultaneously observed the contraction of ionic size, proceed- 

 ing from one rare earth to the next one and denoted this rare-earth con- 

 traction as the "lanthanide contraction." Goldschmidt described his and 

 my work in his posthumously published book Geochemistry , a most 

 fascinating reading, like everything that he wrote. V. M. Goldschmidt 

 was one of the most able men I ever met. Endowed with an immense 

 knowledge and a fabulous memory, he was full of fertile ideas. 



A few weeks prior to the occupation of Norway, I spent a few^ days 

 with him at his home on Holmenkollen near Oslo. He predicted the 

 tragic happenings of the coming years, which very few foresaw. He 

 mentioned that his pupil and former assistant Lunde soon would become 

 a "Gauleiter" of Norway. Lunde was later the Minister of propaganda 

 in the Quisling government. Goldschmidt predicted that the Norwegian 

 coast batteries would fail to fire at the invading enemy, which they in 

 fad did with very few exceptions. He was also endowed with much 

 humor. When Quisling came into power, Goldschmidt was imprisoned 

 and all his property seized. Being short of phosphorus fertilizers, the 

 government released him and instructed him to prepare phosphorus from 

 Norwegian minerals. All his property, however, remained confiscated. 

 When German colleagues passed en route to Rjukan, where they had to 

 inspect the heavy- water works, they called on Goldschmidt. He invited 

 them for dinner, encouraging them to eat with the remark : "Please go 

 on eating, gentleman, all you consume is state property." 



Tracers in Biology 



During the work willi hafnium, I continued the tracer work and in 1928 

 applied radium D and thorium B as tracers in the study of the uptake of 

 lead by bean seedlings and also in the removal of labelled lead by non- 



