3S83.] TAe Constitution oj the Sun • 133 
molten mass, — rifts in the sun’s mantle, through which his 
dark surface is seen ? or, lastly, is the sun a world like our 
own, consisting not only of the same elements, but of land, 
river, and sea ; and are the dark spots which we see but the 
sun’s huge oceans partly laid bare by the rolling back of his 
cloudy covering ? And are our red-flame prominences but 
watery vapour, at one time wafted along by the gentle 
breeze, at another riven and torn by the furious hurricane ? 
And are our pores, granules, and luminous masses but the 
appearances which result when a series of eleCtric discharges 
take place from a mixed conductor, obscured by a semi- 
transparent envelope ? 
In the eleCtric spark we have heat, light, and chemical 
rays nearly — if not exactly — the same as those we receive 
from the sun. While the spark is capable of volatilising 
our most refractory substances, it does not appreciably heat 
the body from which the spark is drawn. But if it meets 
with resistance in its passage from one body to another, 
then heat is generated in proportion to the resistance en- 
countered. 
Now suppose the sun were constituted exactly like our 
own earth, with its green fields, mountains, seas, atmo- 
sphere, and clouds, and all the phenomena pertaining 
thereto ; and, further, that eleCtric sparks were issuing from 
every part of its surface capable of producing a spark. 
How would this supposition compare with what we know 
about the sun ? 
From our knowledge of electricity it is almost certain 
that, owing to varying conduction, the solid parts would 
emit light, varying in quality and intensity according to the 
composition of the matter from which the light emanated, 
and that the liquid parts would emit little or no light. If such 
a conductor were viewed without the intervention of any 
obscuring agent, this unequal luminosity would be distinctly 
seen even at great distances. But if obscured by an atmo- 
sphere more or less saturated with aqueous vapour, then, 
owing to refraction and reflection, the light would be seen 
to be nearly equally dispersed over the whole surface, and no 
inequality would be observed unless when condensation of 
the vapour took place at one part more than another. 
That such local condensation does take place we have 
positive proof, from the faCt that the sun’s atmosphere is 
seen to contain cloud-like masses, which, when examined by 
the spectroscope, give a strong indication of their being 
principally made up of hydrogen gas, an element which in- 
variably results from the decomposition of aqueous vapour 
by the eleCtric current. 
