Vol.. 8, 1922 
PHYSICS: A. S. KING 
123 
The records in figures 9 and 10 contain an almost complete example of 
a free nodal region sustaining itself = 24 cm. above the table, and 
figure 8 gives the acoustic pressures within it. These are largest near 
the pipe, though not quite symmetric and it is possible that the direct ray 
may here influence the resonator. In general, however, i.e., at greater 
distances, the direct ray is relatively ineffective and it is to the occurrence 
of nodal regions alone that the resonator then responds, even when the 
direct ray would seem to have the advantage of nearness. Thus in figure 
10, the curve for f = 0, when tested at the second antinodal plane 
(^R = 36 cm.), although the pipe is now but 12 cm. away, nevertheless 
retains the features of a pronounced minimum. 
* Advance note from a Report of the Carnegie Inst., of Washington, D. C. 
IONIZATION AND ABSORPTION EFFECTS IN THE ELECTRIC 
FURNACE 
By Arthur S. King 
Mount Wilson Observatory, Carnegie Institution of Washington 
Communicated April S, 1922 
In 1914, the publication by P'owler of the series formulae for enhanced 
lines showed that the Rydberg constant "N," occurring in the formulae for 
arc lines, is changed to 4N for enhanced lines. This established the view 
based on a very general difference of behavior in both laboratory and ce- 
lestial sources, that the enhanced lines and the arc lines arise from differ- 
ently constituted emitting centers. The condition pictured by Bohr's 
theory is that the enhanced lines are produced by atoms which have lost 
one electron, while the normal atom emits the arc lines. 
Recent work by Saha applies the relations recognized in physical chem- 
istry to the case when the normal atom is changed into an ionized atom 
with an electron set free. A definite equilibrium is considered as estab- 
lished, represented in the case of calcium by Cal^Z^Ca+ -|- e. 
It follows from this that if we add a large supply of electrons from some 
substance which becomes ionized more readily than calcium, fewer electrons 
from the calcium can exist in the free state, and the proportion of Ca+ 
atoms becomes less, with a corresponding weakening of the enhanced 
lines relative to the lines of the normal atom. 
In the electric furnace, the enhanced lines of some substances can be 
produced faintly, and the effect of a mixture with an easily ionized sub- 
stance may be tested, under the same conditions of temperature and pres- 
sure for the mixture as for the pure substance. Experiments have been 
