Physics. 265 
heat. The effect produced by the rays of the sun on ne surface of the 
earth in one minute is thonctory 5°5 cubic miles of h 
20,589,000 poner * miles; the surface of this sphere would be equal 
to 5326 billions of squa miles. ‘The. surface seared by the intersec- 
tion of this hollow io and our globe, or the base of the cone of solar 
light which reaches our earth, stands to the whole pa of this hollow 
sphere as ae : 326 billions, or as 1 to 2300 millions. This is the 
ratio of the ag received by our globe to the whole amount of heat sent 
forth from the sun, hoes eas! in one minute amounts to 12,650 mil- 
lions of cubic miles 
to affect uniformly its hats mass, the tem mperature of the sun ought to 
decrease 1°-8 C. yearly, and for the historic time of 5000 years this Joss 
would Sinscouatle amount to 9000° C. 
uniform cooling of the whole of the sun’s huge mass cannot, how- 
ever, take place ; ; on the ponent | if the radiation were to occur at the 
expense of a Bree store of heat or radiant power, the sun would becom 
covered inas space of time wit a cold oa whereby radiation 
sun through countless centuries, We tay assume with mathematical 
certainty the OR of some compensating influence to jeu good its 
enormous los 
Is this restoring ; agency a chemical process ? 
If cg he case, the most favorable camepnen, would be to 
okie mass of the sun to be one lump o , the combus- 
tion of por kilogram of which produces 6000 units ta of ati Then the 
sun would only be able ‘o sustain for forty-six centuries its present e expend- 
iture of light and heat, not to mention the oxygen necessary to keep up 
such an immense combustion, and ate unfavorable circu ces. 
The revolution of the sun on his axis has been suggested as the cause 
oa radiating energy. closer RES proves this hypothesis 
able. 
Rapid roars i sk friction or resistance, cannot in itself alone be 
as a cause of light and heat, especially as the sun is in no way 
to be disGngaishad’ oes the other bodies of our system by velocity of 
axial ro ane The sun turns on his axis in about twenty- ee days, 
ter is nearly 112 times as ace as t , from 
which i it t follows that a point on the ar equator Gives but a little 
more than four times as quickly as a ‘aoe on the earth’ 's equator. 
largest planet of the dre system, whose diameter is about yyth that of 
the sun, turns on its axis in less than tem hours; a ‘pores on its equator 
resolves about six pres yuicker than one on "the solar equator. The 
outer ring of Saturn ex the sun’s equator more than ten times in 
No. 107. 
sa Scr.—Seconp Serres, Vou. XXXVI, 
34 
