210 ANNUAL REPOKT SMITHSONIAN INSTITUTION, 1935 



total negative component would have an upper limit of one-quarter 

 of the total charged component. At sea level the excellent measure- 

 ments of Millikan and Neher conspire toward a more conclusive 

 analysis. At the equator the asymmetry shows that 10.4 percent of 

 the sea-level intensity is from unbalanced positives. In Panama the 

 figure is 12 percent. The difference, 1.6 percent, is the amount of 

 latitude effect which can be accounted for by the unbalanced positives. 

 This agrees with the average of Millikan and Neher's measurements 

 of the total latitude effect, and it is concluded that negatives in the 

 corresponding range of rigidity make no appreciable contribution to 

 the sea-level intensity. This estimate is based upon the asymmetry 

 measurements in Panama. If those at the Equator had been used 

 instead, a larger latitude effect than that found would have been 

 expected. Theory indicates no important differences between the 

 asymmetries at the Equator and in Panama, and the latter measure- 

 ments appear to be the more reliable on the basis of the probable 

 errors. 



For the analysis of rays of lower rigidity the measurements in 

 higher latitudes are ready and awaiting the completion of the accu- 

 rate theoretical calculations of cut-off angles. Higher rigidities, on 

 the other hand, can never be analyzed by this method, as the earth's 

 field is too weak. 



Lower limits for the intensity in high latitudes of the entire 

 charged component, positives and negatives combined, can be given 

 without further delay. For this purpose it is only necessary to add 

 the unbalanced positive component at the Equator to the measured 

 values of the latitude effect. Expressed in terms of the total inten- 

 sity at the Equator, at least 16 percent of the sea-level intensity and 

 30 percent of the intensity at 4,300 meters in latitudes above 50° is 

 due to charged primaries. These figures represent lower limits from 

 two points of view. In the first place the correction for possible 

 negatives at the equator has not been taken into account, though it 

 has been shown this is not necessary at sea level. The more im- 

 portant point is that much of the unanalyzed intensity at the Equa- 

 tor may also be due to charged rays of higher rigidities. It might 

 well be argued from similarities in the absorption that the unre- 

 solved equatorial radiation is of the same character as the radiation 

 known to be charged, but this type of reasoning is obviously less 

 reliable than that used in the above analysis. 



Now comes the question of what these unbalanced positive rays 

 are: Table 1 suggests three possibilities. The first is the positive 

 electron, a particle of very nearly zero mass and unit positive charge. 

 Rays of this type are often produced when high energy gamma rays 

 collide with atomic nuclei, and they are also generated in certain 



