x THE STARRY HEAVENS 387 
sium, ete., in all 36 of our terrestrial ele- 
ments, while as regards some others the 
evidence is not conclusive. We cannot as 
yet say that any of our elements are absent, 
nor though there are various lines which can- 
not as yet be certainly referred to any known 
substance, have we clear proof that the Sun 
contains any element which does not exist on 
our earth. On the whole, then, the chemical 
composition of the Sun appears closely to 
resemble that of our earth. 
THE PLANETS 
The Syrian shepherds watching their flocks 
by night long ago noticed —and they were 
probably not the first —that there were five 
stars which did not follow the regular course 
of the rest, but, apparently at least, moved 
about irregularly. These they appropriately 
named Planets, or wanderers. 
Further observations have shown that this ir- 
regularity of their path is only apparent, and 
that, like our own Earth, they really revolve 
round the Sun. To the five first observed — 
