724 Prof. Harkins and Mr. Wilson on Energy Relations 



elements points to the fact that positive electricity must also 

 have a discrete structure. The mass of a particle of positive 

 electricity, which may be called the positive electron, must 

 be greater than that of a negative electron, but the positive 

 electron is smaller in size. 



Two theories exist concerning the positive electron, one 

 due to Rutherford and one to Nicholson. Rutherford has 

 concluded from his work on the passage of alpha rays 

 through matter that the hydrogen nucleus is the positive 

 electron. On the other hand, Nicholson, from his work on 

 the spectra of the nebulas, has come to the conclusion that 

 they contain elements with simple nuclei of charge le, 2e, 

 3e, &c, and that the atomic weight of the element with 

 nucleus le, which he has called protohydrogen, is about 

 ■0*081. He considers that the nucleus of hydrogen contains 

 a certain number of these positive electrons, and one less 

 negative electrons, so that the resultant charge on the 

 nucleus is le, as experiments show. Hydrogen is con- 

 sidered to be an evolution product of the system le, helium 

 an evolution product of the system 2e, and the other complex 

 elements evolution products of the other simple elements 

 with higher charges on their nuclei. It must be remem- 

 bered that the atomic weights of Nicholson's elements of 

 simple nuclei are dependent on the work of Bourget, 

 Buisson and Fabry, and were obtained using their inter- 

 ference method for the examination of some of the lines of 

 the nebulas. It has been shown by Michelson, and Bourget, 

 Buisson and Fabry, that the widening of certain spectral 

 lines varies as the square of the molecular velocity. For 

 this to hold, however, the line must be of a certain simple 

 type, and it is perfectly possible to obtain widely differing 

 values for the atomic weight by using different lines in the 

 spectrum of the same element. Moreover, the accurate 

 measuring of the faint nebular lines is a difficult matter. 

 The accuracy of the weights as given by Nicholson would 

 seem, then, to be open to question. 



Nicholson's system for the structure of the elements found 

 on the earth fails to account for several very important facts. 

 Calculations show that the probability that the sum of the 

 •deviations of the atomic weights of the elements from whole 

 numbers should accidentally be as small as it is, is only one 

 in fifteen million. Also, there must be some reason for 

 the fact that in radioactive disintegrations only helium is 

 evolved, and not hydrogen. From the standpoint of Nichol- 

 son's theory of the structure of the elements, the regularity 

 found in the atomic weights remains as much of a mystery 



