426 THE BEAUTIES OF NATURE CHAP, 
such a nebula as that in Andromeda, which 
with our most powerful instruments appears 
only as a mere cloud, is really a vast cluster 
of stellar points. 
This, however, by no means applies to all 
the nebule. The spectrum of a star is a 
bright band of colour crossed by dark lines; 
that of a gaseous nebula consists of bright 
lines. This test has been made use of, and 
indicates that some of the nebule are really 
Immense masses of incandescent and very 
attenuated gas; very possibly, however, in a 
condition of which we have no experience, and 
arranged in discs, bands, rings, chains, wisps, 
knots, rays, curves, ovals, spirals, loops, 
wreaths, fans, brushes, sprays, lace, waves, 
and clouds. Huggins has shown that many 
of them are really stupendous masses of 
glowing gas, especially of hydrogen, and 
perhaps of nitrogen, while the spectrum also 
shows other lines which perhaps may indicate 
some of the elements which, so far as our 
Karth. is concerned, appear to be missing 
between hydrogen and lithium. Many of 
the nebule are exquisitely beautiful, and 
their colour very varied. 
