Celestial Bodies 143 
news that such a planet had been observed in transit across 
the sun's disk (a planet in crossing the surface of the sun ap- 
pears as a dark spot—transits are quite rare) by a French 
amateur astronomer, and a name was proposed for the new 
planet, Vulcan. The “discoverer” even received the decora- 
tion of the Legion of Honor from the French Government. 
However, subsequent observations of Vulcan have never 
been made, or have been disproved, so that today we no 
longer accept Vulcan into the solar family. But the anomalous 
motion of Mercury still persists, and in fact this deviation 
from classical theory has become one of the strong arguments 
for the Theory of Relativity as developed by Einstein, a 
theory which has an explanation for Mercury’s erratic be- 
havior. 
VENUS, THE VEILED GODDESS 
The planet Venus, named after the Roman goddess of 
beauty and love, is about the size of the earth, but so en- 
shrouded with mists and veiled in clouds that no one has 
ever seen her surface. Scientists, in their rude attempts to 
probe her mysteries, have applied the spectroscope to her, 
but have learned little about her except some notion about 
the chemical constitution of her outer atmosphere. As Venus 
takes different positions with respect to the earth in space, 
she sends us different amounts of light. At her brightest she 
is visible to the naked eye in full daylight, if you know where 
to look for her. 
Twice, in little over a century, Venus crosses the disk of 
the sun. The event is called a Transit of Venus. It is so rare 
that Captain Cook, the old navigator and discoverer of 
Pacific islands, brought an expedition all the way from Eng- 
