242 Wisconsin Academy of Sciences, Arts and Letters. 



TABLE I, 



The numbers in column 1, table 1, represent the polar radii of similar el- 

 liptic layers or shells composing an oblate ellipsoid. The numbers in col- 

 umn 2 are the differences between the cubes of 31 anl 30, 30 and 28, 2S and 

 26, etc. As the volu-nes of similar oblate ellipsoids vary as the cubes of 

 their polar radii, the numbers in column 2 are proportional to the volumes 

 of the component layers. The mean density of the earth as attained by 

 experiments is, at least very neerly, |f^ tim s that at surface. Toe whole 

 mass of the earth, then, may be represented by 31 cubed multiplied by ff , 

 or 56745, or by 56745 divided by 56745. The first number in column 3 is so 

 assumed as to give the requisite mass in the earth under the law that the 

 increasv3 in compression or density varies as pi'essure. The other numbers 

 in this column are computed and show the increments in density from 

 layer to layer. The numbers in column 4 are the computed densities of 

 the layers, and those in column 5 divided by 56745, the masses. The pres- 

 sure of the outside layer compare 1 with that of any other, varies as the 

 attraction of the ellipsoid on the masses of these layers. The increment 

 of denity for the pressure of any interior layer is found by multiplying 

 the assumed increment .12675 by the pressure of the interior layer divided 

 by the pressure of the outside layer. 



