es re ee ea eee 
SECTIONAL TRANSACTIONS.—A. 359 
5. Dr. R. J. Prrrsou.—Pulling Electrons from Metals by Intense 
Electric Fields. 
The tube contains electrodes made from molybdenum plates pressed into 
hemispherical shells, welded to tungsten rods which are sealed into a hard glass 
tube. The discharge gap is 0.023 cm. A charcoal bulb is attached which is 
kept at 386° C. The electrodes are heated to 1,400° C. by induction furnace, 
the tube is baked at 500° C., the vacuation covering forty-eight hours. The 
connected tube and bulb is sealed off. The bulb is placed in liquid air and the 
discharge tube is heated at 500° C. for two hours. Then the tube is slowly 
sealed off from the charcoal bulb. The critical gradient is 5,400 Kv/cm. This 
minimum potential is sharply defined, showing that proper outgassing com- 
pletely eliminates field currents, thereby giving a definite gradient of cold 
electronic discharge. 
6. Dr. Ann C. Davres.—-The Metastability of the Fundamental 
Coplanar Condition of the Heliwm Atom. 
Further experimental evidence bearing on the conclusions of Horton and 
Davies that an emission of radiation results from the displacement of an electron 
within a helium atom from the normal orbit (the fundamental orbit of the crossed 
system) to the first outer orbit (the fundamental orbit of the coplanar system), 
and that this radiation can be absorbed by normal helium atoms, these con- 
clusions being at variance with the conception of the fundamental coplanar 
condition of the helium atom as a metastable state. 
7. Prof. H. N. Russevu.—The Spectrum of Titaniwm. 
8. Prof. Frank Autey.—Visual Sensory Reflexes. 
In endeavouring to discover the fundamental processes of colour vision, 
experiments were conducted by fatiguing the left eye with a series of mono- 
chromatic spectral colours and making measurements of the effects produced 
on the right eye. ‘The method used was the measurement of the critical fre- 
quency of flicker. In these experiments the dark room was discarded and the 
eye was maintained in ordinary daylight adaptation. The results showed the 
existence of visual sensory reflexes, the chief effect of which is to enhance the 
sensitiveness of the receptors of all three fundamental colour sensations in 
the right eye. 
In a similar manner the right eye was fatigued, and it was found that 
both direct and reflex effects were simultaneously produced. The simple 
colours—red, green and violet—affect one sensation directly and two reflexly. 
The compound colours—orange, yellow and blue—affect two sensations directly 
and one reflexly. No doubt all colours affect all three sensations both directly 
and reflexly, but the experiments give the net final results. 
Similar experiments were tried by confining fatigue to one side of a retina 
and measuring the reflex effects produced on the other side. They were pre- 
cisely the same as in the binocular experiments. 
The reflex principle seems to give an adequate explanation of a monocular 
and binocular contrast, positive and negative after-images, and the general 
phenomena of colour vision. 
The results strongly confirm the three-components theory of Thomas Young. 
9, Mr. F. J. W. Wurepits.—An Experiment Illustrating the Theory 
of the Green Flash. 
When the sun sets under favourable conditions the last glimpse appears a 
brilliant green. f 
The theory that the phenomenon is due to the simultaneous action of disper- 
sion and absorption is now generally accepted. The experiment is designed to 
illustrate this theory. 
