l88 3 -3 
The Constitution of the Sun . 
*35 
neck of the funnel towards the opening, the general surface 
of the paper appears more or less illuminated according to 
its transparency, while the borders of the aperture are more 
brightly illuminated and are surrounded on the inner side 
by what at first sight appears to be a halo terminating in a 
dark central portion, but which, on further examination, is 
found to be a reduced image of the opening reflected from 
the water to the eye. In fadt, with a small tuft of cotton- 
wool over the aperture, and a pan with irregular bottom 
underneath, it is possible to produce all the appearance 
peculiar to sun-spots. 
From these appearances alone we might be able to find 
an explanation for spot phenomena, but fortunately in this 
case we do not require to depend altogether on appearances, 
as from the indefatigable labours of our spedtroscopists we 
learn that spot spedtra are not the same as spedtra from any 
other parts of the sun’s surface, but show signs of increased 
absorption, the point of greatest absorption being at the 
centre, and decreasing therefrom towards the edges. 
Now, if our supposition that spots are openings in the 
sun’s clouds over water be corredt, it follows that all rays of 
light travelling from the shores of the oceans, or from the 
waters of the oceans, over which we suppose visible spots 
are formed, will require to cross each other before they can 
pass through these openings, and that the points of maximum 
crossing will be at or near the centres, and that the points 
of minimum crossing will be at the edges of the openings. 
Let us compare this optical fact with what we know about 
spot spedtra. The point, in our hypothetical spot, where 
the greatest number of rays cross is at the centre, exadtly 
corresponding to the part where we find the greatest absorp- 
tion in sun-spots. The point of least crossing is at the 
edges, where we find little or no increased absorption in sun- 
spots. Again, the lines that show by far the greatest ab- 
sorption in sun-spots are those belonging to sodium and 
hydrogen. What does this fadt point to ? Is it to the 
emanation of an excess of the feeble monochromatic light of 
sodium and hydrogen from the oceans beneath ? and are we 
to infer therefrom that direbtly beneath the spots there is 
not only water, but sea-water, the same as which is laving 
our own shores ? 
This latter question contains much more than it would at 
first appear to indicate. It is not a question merely as to 
the presence of an excess of sodium or hydrogen light, but 
also, first, as to whether or not the presence of metallic 
vapours in the sun’s atmosphere is necessary in order to 
