524 
2. When the lines are classified according to intensity, then, 
within each intensity class, the amounts of displacement are ‘still 
widely different from line to line; but if for each intensity class 
the mean displacement is taken, those mean values appear to depend 
on intensity according to a peculiar law, predicted on the basis of 
the dispersion theory (these Proc. XIII, 10 (1910); Arch. néerl. III A, 
tome IV, p. 59, 1917). 
3. The amount of displacement of a Fraunhofer line depends on 
the presence of closely neighbouring lines. A companion on the red 
side reduces, a companion on the violet side augments the displace- 
ment of a line towards the red, as if the components of close pairs 
of lines repel each other. 
The way in which these three characteristic properties of the 
displacements of Fraunhofer lines may be deduced from the theory 
of dispersion lines, has been indicated by one of us in some of the 
above-mentioned publications (The Observatory 87, 252; Astroph. 
Journ. 40, 1; 48, 43; Arch. néerl. III A, tome V, 116). 
Recently we have once more rigorously inquired into the third 
point, because it supplies what is probably the most convincing test 
as to the correctness or otherwise of our interpretation of the solar 
spectrum. 
Fresh evidence in favour of the view that the distribution of the 
light in Fraunhofer lines is governed by anomalous dispersion. 
The assertion that neighbouring Fraunhofer lines might, by ano- 
malous dispersion, influence each other to an appreciable degree has 
been strongly opposed by EversHep, Larmor, and Sr. Jorn. The 
latter says a.o. “While anomalous refraction may produce sporadic 
effects under occasionally favourable density gradients in the solar 
atmosphere, the conclusion from investigations and observations at 
this observatory is that, within the present limit of precision of 
measurement, the positions of the Fraunhofer lines in the spectrum 
of the solar disk are not systematically affected by anomalous 
dispersion.” *) 
We ‘are able to prove, on the contrary, that from certain obser- 
vations made on Mount Wilson with excellent apparatus, much 
experience, great care, and perfect impartiality, the existence of the 
mutual influence in question may be derived with a probability of 
about 500 to 1. 
1) Cu. E. Sr. Jorn, Astroph. Journ. 46, 250 (1917); Mt. Wilson Contrib 
N°, 138, p. 2. 
