PROCEEDINGS OF THE POLYTECHNIC ASSOCIATION. 717 



from burning coal, or other fuel, was a reproduction of that which 

 had, at one time, been absorbed by vegetable structures from the 

 sun. 



Under the operation of the laws and forces before mentioned, 

 the sun has become, as we see him, a molten mass of incandescent 

 matter, glowing with intense light and heat. 



On examining the sun with a telescope, we discover that his disc 

 is not uniformly bright. There are scattered upon it, small dark 

 spots, which are in a state of continual change, and again there are 

 large black spots, surrounded by penumbra, which are gradually 

 shaded down from the black central part to the white light. They 

 change from day to day, and even from hour to hour. They break 

 up or contract, and finally disappear. They show all the signs of 

 mol^ility, characteristic of masses floating in molten liquid, and of 

 melting and passing away. The spots are confined to a zone 

 extending 30° each side of the equator, and they seldom con- 

 tinue longer than five or six weeks. They appear to occupy deep 

 cavities in an incandescent gaseous, or semi-gaseous envelope, or 

 covering of a molten sea, and their penumbra indicate what we 

 might expect from currents, converging and flowing in from the 

 hot gaseous atmosphere over the dark cavity. 



There are sometimes seen, peculiarly marked lines, brighter 

 than other parts of the surface which are curved, or deviate in 

 branches. These are apparently inmiense waves on the solar sea, 

 and seem to give evidence of disturbing causes there, as well as 

 here producing winds, waves, currents, etc., only on a much 

 larger scale. 



Many ftmciful notions have been broached on this subject. One 

 is that these spots are the dark solid body of the sun itself, laid 

 bare to our view through openings in its luminous atmosphere. 

 Laland suggests that eminences in the nature of mountains are laid 

 bare and project above the luminous ocean: appearing black above 

 it. How he supposed these cold mountains got covered again in 

 the course of five or six weeks we are left to conjecture. 



This hypothesis of a cold sun with a luminous atmosphere is 

 quite in keeping with that other hypothesis, which is based on the 

 assumption of a cold opaque sun, invested with a luminous or phos- 

 phorescent atmosphere, whose rays, in passing through our atmos- 

 phere, become heated by friction. 



All such notions of a cold sun, and of cold sun-beams, bring in 

 to us no other genial heat than what they get by friction in our 



