Nr. 6] KVAHTÆH-STIIDIKH I rMONDII.IKMSI-ELTK T 47:'> 



led for life til gjensland for en leniinelii^ iilførlig behaiidliiii* 

 og kom til del resullal, al whatever mav have heen Ihe hue 

 hislory of oiir almosphere, il seems cerlain Ihal if sunlighl was 

 ready. Ihe earlh was ready, bolh for vegelable aiid animal life, 

 if nol wilhin a cenlury, al all evenis wilhin a few hundred 

 eenluries afler the rocky consolidalion of ils surface. Hul was 

 Ihe sun ready? The well founded dynamical Iheory of the sun s 

 heat. carefully worked out and discussed by Hi:LMHOi,rz, Xkw 

 COMB, and myseif, says \() if Ihe consolidalion of Ihe earlh 

 look place as long ago as lifly million years; the solid earlh 

 must in Ihal case have waited Iwenly or thirly million years 

 for Ihe sun lo be anylhing nearly as warm as he is al present 

 If the consolidalion of Ihe earlh was linished Iwenty or twenty 

 live million years ago Ihe sun was probably ready Ihough 



probably not then (|uite so warm as al present, yel warm enough 

 lo support some kind of vegelable and animal life on the earlh 

 (Smilhsonian Rej)orl for 1S1)7, pag. o56 — ooT . Men herlil be 

 merker (æambkki.in: >lhe dealing out of this aniounl of heal 

 mav hypolhelically have occu|)ied a |)erio(l many limes Ihe 

 Iwenty or Iwenly live million years |)ostulaled Smilhsonian 

 Heporl for ISUll, pag. 240 — 241); og videre forlsjetler han: 1 

 again beg lo incjuiie whelher Ihere is al present a solid basis for 

 any »sure assumplion wilh reference to the earlh's early Ihermal 

 condilions, eilher inlernal or external, of such a delerminate 

 nature as lo place any slrict limitations upon Ihe duration ol" 

 life« (L. c. pag. 245). Og ganske nylig har I5i:(:ki:h behandlet 

 spørsmaalet ul fra el helt andel synspunkt og sier: If il is 

 granted thai the compensation level is an euleclic level, and 

 Ihis seems Ihe only inlelligible Iheory. the age of an earlh healcd 

 holh by compression and by radioaclivily can be computed 

 (leodesists assert thai the compensalion level is between lin 

 and 14(1 kilometers from the surface. The smaller deplh woidd 

 correspond lo an age so small as lo be u uacceptable lo geologists 

 For a deplh of 121 kilometers the age would be <)S ]()''yeais 

 and one sevenlh of Ihe heat emilled would be due lo radioat- 

 livity. For a de|)lh of 1 4(i kilometers the age would be Kto ](i" 

 years and 2() per cenl ol the heal lost woidd be ascribable to 

 radioaclivily. (irealer depths ol Ihe compensation level seem 

 incompalibie with slight slrain benealh Ihal level Hkckkh 

 >Isoslasy and Madioactivily Hull (leol. Soc America, \'oi 



2<), nnT), pag. 20:'.l Og i fuld overensslemmelse hermed ullaler 

 saa liKCKKU videre: Il has olien been asserli'd thai Ihe discoveiy 

 of radioaclivily inileliuilely |)rolongs Ihe probable age of Ihe 

 earlh. To me il seems thai the delerminalion of Ihe level of 

 compensalion linnls bolh llic age ot Ihe earlh and Ihe amounl 



