ABSTRACTS 



325 



The diagram in Fig. 3 brings out the well-known fact that for 

 the heavier elements both the longest L waves and the shortest ones 

 as well follow closely the Moseley Law, i.e., that VF is proportional 

 to At. No. The diagram also shows that for the lighter elements 

 from lithium to chlorine the square roots of the critical voltages 

 cited follow a similar law, but the proportionality factor between 

 \/V and At. No., however, is not the same for the lighter elements as 

 for the heavier ones. It is evident that according to the representa- 

 tion a break occurs at or near chlorine or argon. 



The paper also points out that in a series of brilliant experiments 

 Millikan^ and his associates recently succeeded in photographing ex- 

 treme ultra-violet spectra of light elements as far down as X 136.6 A 

 and that from the results determinations were made by him of the 

 quantum voltages of the limiting frequencies of the L series of the 

 elements from Lithium to Magnesium. The photographic results 

 also enabled him to estimate quantum voltages corresponding to 

 the first members of the L series for these elements. These are given 

 in Table V and along with them are given critical voltages found by 

 Horton and Davies for Neon and a critical voltage found directly by 

 Holweck for Aluminium. 



TABLE V 



iMillikan. Proc. Nat. Acad. Sci. 7, p. 289, 1921. 



^From direct determinations. Horton and Davies. Proc. Roy. Soc, No. 98, 

 p. 121, 1920. 



'From direct determinations. Holweck. Ann. de Physique, Jan., Feb., 1922. 



