"He has enlightened our globe from one generation to another without any apparent diminution of strength, and we have formed the instinctive belief that no limit in the past or any in the future can be assigned to his functions. No proof of progress or decay has been detected ; and it has been thought that nothing but the fiat of the Almighty can quench his rays. Principles have now been recognized, however, which enable us to assign limits, and to show that he has not shone from a past eternity, and that he has a limited existence as an incandescent body. This limit assigned to the solar system forces us to recognize the hand of a Creator."
"The meteoric stones that sometimes fall to our earth may be regarded as balls, but moving with much greater velocity. They strike against our atmosphere with so much force that the force is converted into heat, so intense that they glow or become incandescent. .... Assuming that the heat of the sun has been kept up by meteoric bodies falling into it, and proof has been given of such fall, it is possible from the mass of the solar system to determine approximately the period during which the sun has shone as a luminary"
"Limits can be set to the fuel of the solar system, and therefore limits can also be assigned to the existence of the sun as our luminary. The limits lie between 100 millions and 400 millions of years. These are enormous periods, but still they are definite. The mass is so great,and the cooling is so slow, that, even on the supposition that no fuel was added, it might be five or six thousand years before the sun cooled down a single degree."