32 MAGNITUDE, FIGURE, AND 



our planet have already been so far treated of in detail, 

 (Kosmos, Bd. i; S. 176178 and 424, Anm. 6 ; Engl. p. 159 

 160 and 404), that it will be sufficient to subjoin here the 

 result of the fresh experiments by Reich in 1847 and 1850, 

 published in a later memoir by that indefatigable investi- 

 gator^ 27 ) According to the present state of our knowledge, 

 the results of the three methods are the following; the 

 density of water being taken as unity. 



The Schehallien experiments ; mean of Playfair's 



maximum 4*867, and his minimum 4*559 .... 4*713 

 Pendulum observations at Mont Cenis, by Car- 



lini, with Giulio's correction 4*950 



Torsion Balance; Cavendish, according to 



Baily's calculation 5*448 



Reich, 1838 5*440 



Baily, 1842 5*660 



Reich, 18471850 5*577 



The mean of the two last results gives the density of the 

 earth 5 '62; much exceeding, therefore, that of the densest 

 and finest-grained basalts (according to Leonhard's nume- 

 rous experiments, from 2*95 to 3*67) ; exceeding that of 

 magnetic iron ore (4'9 5'2) ; and but little inferior 

 to the native arsenic of Marienberg or Joachimsthal. 

 I have already remarked (Kosmos, Bd. i. S. 177; Eng- 

 lish edition, p. 160), that, viewing the great proportion of 

 the visible strata of our continents which are secondary, 

 tertiary, or alluvial, (the collective extent of volcanic or 

 basaltic islands is exceedingly small,) the average density of 



