SOLAR ECLIPSE EXPEDITIONS— MITCHELL lg5 



The table takes account of all the Fe lines in well-defined mul- 

 tiplets. Altogether a total of 48 miiitiplets involving 309 lines were 

 discussed, the material being divided into 3 series, strong, medium, 

 and weak multiplets. In each case are given the number of lines 

 involved, the height in kilometers from the flash spectrum and AX 

 (in units of 0.001 angstroms), which is the equivalent to the difference 

 sun minus vacuum arc from which has been subtracted in each case 

 the relativity shift. 



From the abundant material that went into the table, it is evident 

 that in addition to the relativity shift to the red, corresponding in 

 the table to AX=0, there are other effects present. For the strong 

 lines, those of small excitation potentials and greater heights, the 

 value of AX is positive while for the weak lines, those of higher excita- 

 tion potentials and lesser heights, the values of AX are essentially 

 negative. The systematic differences between strong and weak lines 

 is most readily explained as a Doppler shift caused by a circulation 

 of vapors in the sun's atmosphere. On account of the higher tem- 

 peratures and higher pressures near the photosphere, the solar activity 

 causes the Fe atoms to ascend through the medium of thousands of 

 weak lines of high excitation potential, the maximum velocity of 

 ascent found for Fe being 0.2 km per second. The heights to which 

 these atoms are ejected are much greater than can be measured by 

 the lines in the flash spectrum. In the upper reaches of the chromo- 

 sphere, especially where the pressures are minute, some of the atoms 

 lose an external electron and become ionized. 



From the law of nature that "whatever goes up must come down," 

 the Fe atoms descend from the maximum heights. In their descent 

 some of the ionized atoms gain an external electron and again become 

 neutral. According to this interpretation, in a direct photograph of 

 the sun showing its mottled surface the atoms ascending from the 

 sun exhibit themselves over the small bright granules and the descend- 

 ing atoms over the large dark interspaces, the observed effect being 

 an integrated one. 



As an illustration of the correlations found to exist between different 

 solar values, there are given in tabular form the quantities involved 

 in the dozen lines of a composite multiplet of Fe. More than 100 

 times as many atoms aie active in producing the strongest line at 

 3820 A as go to form the weakest one at 3940 A. The relativity shift 

 amounts to 0.0082 A. Hence, wdthin a single multiplet the heights 

 found directly from the flash spectrum, or indirectly from the Evershed 

 effect in sunspots, are not constant but are the greatest in size for 

 those lines which involve the largest number of atoms. 



