PROTIUM — DEUTERIUM TRITIUM TAYLOR 



127 



tooling votf^' 



I I I I I I I I I I I 

 Scale " cm. 



aofiny iMiter. 



lb arculafing 

 pump 



of mass 1 and zero charge. Both of these changes have now been 

 decisively demonstrated not only by the methods of Rutherford 

 involving measurements of the tracks of particles; they have been 

 employed to produce these rare isotopes " in quantity." Samples of 

 deuterium after subjection 

 to such atomic bombard- 

 ment in apparatus shown 

 in figure 2 and plate 3 have 

 been found by the Prince- 

 ton physicists to contain 

 concentrations of tritium 40 

 times greater than that of 

 the deuterium initially. 

 Similarly, the production 

 of helium isotope of mass 3 

 has also been shown. In 

 each case the method of 

 analysis involves the sensi- 

 tive mass spectrograph al- 

 ready discussed. Deutons 

 also are being used as the 

 projectiles for the produc- 

 tion of artificially radio- 

 active light atoms, the new 

 field of physics developed 

 only this last year by M. 

 Joliot and his wife, Mme. 

 Curie Joliot, first with al- 

 pha particles, next with 

 protons and neutrons, and 

 now also with deutons. 



That the pace of this 

 scientific development is 

 prodigious all must realize 

 when they remember that 

 only a year ago the deu- 

 terium isotope was not yet 

 isolated. Today it has a 



still rarer brother, tritium ; it has itself given rise to this and to other 

 new isotopes, some radioactive, some not ; it has made possible a new 

 branch of chemistry, the chemistry of isotopes, which already has 

 markedly enriched our knowledge of general and physical chemistry ; 

 it is a potent weapon of attack also on physiological and biological 

 problems. 



FiGDRE 2. — Diagrammatic sketch of transmuta' 

 tion tube. Deuterium in the upper half ia 

 ionized and the deutons are led through the 

 slit or canal, between the shaded areas, to the 

 lower half of the tube in which they collide, 

 under high potential, with deuterium atoms 

 and molecules to give the observed transmuta- 

 tions to tritium and to helium 3. The gas is 

 constantly circulated between the upper and 

 l-ower halves of the canal ray tube. 



