456 On Electricity and its Present Applications. [August, 
with objects at the side of the horizon opposite the luminous 
segment. Such objects, which were previously sharply 
illuminated by the setting sun, and were then shadowed by 
the dark segment, appear at this time once more bathed in 
a faint reddish light. The maximum of this second illu- 
mination occurs in the Alps when the sun is 4 0 or 5° below 
the horizon. The centre of the purple light is at this time 
about 1 8° above the horizon, whilst its upper limit may rise 
to an altitude of 40° to 50°. 
As the purple light vanishes behind the luminous segment 
there appears at the opposite side of the heavens a second 
dark segment. Soon, also, as the first luminous segment 
descends, there appears above it a second, not readily dis- 
tinguishable from it, and if the sky is very clear there is 
sometimes perceived a second purple light , and therewith a 
repeated increase of light, so that objedts on the opposite 
side of the horizon are illuminated for the third time. 
The occurrence of two distindt periods of red (rosy or 
purple) tones, which was dwelt upon by a number of ob- 
servers as something charadteristic of the twilights of last 
winter, is therefore a normal phenomenon, though rarely 
witnessed in such intensity. 
The excitement which the recent sunsets produced were 
especially due to the unusual intensity of this second 
“purple light,” which on some occasions seemed to surpass 
the first one both in extent and splendour. 
III. ON ELECTRICITY AND ITS PRESENT 
APPLICATIONS* 
By W. Fraser, A.M., M.R.C.S. Eng. 
(Concluded from page 409.) 
* ATTER, as it exists in the ether or chaos, is probably 
in its simple or atomic, and not in the molecular 
form, as it for the most part appears in the earth. 
We know that Eledtron alone does not conduce to the union, 
but, on the contrary, to the dispersion or repulsion of the 
* Read at the Aberdeen Philosophical Society, February 5th, 18S4. 
