1HE NORMATIVE AVERAGE DENSITY 



387 



Table I. — Densities anil Specific Volumes of normative Minerals — Continued 



Albite 2.597* 



Anorthite 2 . 757* 



Leucite 2.48 



Nephelite 2.619 



Corundum 4 . 00 



Wollastonite (CaSi0 3 ) 2.906* 



Enstatite (MgSiO s ) 3.183* 



Ferrosilite (FeSi0 3 ) 3.90 



Forsterite (Mg 2 Si0 4 ) 3.216 



Fayalite (Fe 2 Si0 4 ) 4.318 



Magnetite 5 . 17 



Ilnienite 4.7 



Apatite 3.2 



v Remarks 



.3851 Artificial. Day and Allen, Car- 

 negie Publication number 31, 

 1905, page 58. 



.3627 Artificial. Day and Allen, work 

 cited. 



.4032 Natural. Dana, System. 



.3818 Artificial. Bowen, American 

 Journal of Science, volume 43. 

 1917, page 115. 



.250 Natural. Dana, System. 



.3441 Artificial. Allen and White, 

 American Journal of Science, 

 volume 21, 1906, page 92. 



.3142 Artificial. Allen and others, 

 *] American Journal of Science, 

 volume 22, 1906, page 396. 



.2564 Calculated from unpublished an- 

 ! alyses of natural enstatite and 

 hypersthene by Adams and 

 Washington. 



. 3109 Artificial. Bowen, American 

 Journal of Science, volume 37, 

 1914, page 498. 



.2316 Natural from Rockport, Massa- 

 chusetts. Penfield and Forbes. 

 American Journal of Science, 

 volume 1, 1896, page 130. 



.193 Natural. Dana, System. 



.213 Natural. Dana, System. 



.313 Natural. Dana, System. 



RESULTS 



In Table II are given the average chemical compositions of the conti- 

 nents and of the floors of the Atlantic and Pacific oceans. With them 

 are also given the estimated average altitudes of the continents, as esti- 

 mated by Wagner, 12 and the average ocean depths, as estimated by 

 Murray. 13 The average densities, both on a water-free and a water-bear- 

 ing basis (as explained later), are also given. These values for density 

 and elevation differ somewhat from those given in my former paper, 14 

 the former because new values have been adopted for the densities of the 



* Calculated to density by R. B. Sosman. 



12 H. Wagner : Lehrbuch der Geographic, vol. i, 1912, p. 284. 



13 J. Murray : Scot. Geog. Mag., vol. iv, 1888, pp. 30 and 34. 



u H. S. Washington: Jour. Franklin Inst., vol. 190, 1920, p. 801. 



