OCTOBEE 25, 1907] 



SCIENCE 



537 



with the harmonic of this type. The com- 

 bined effect of all the harmonics of the 

 third degree is shown in Fig. 13. It repre- 

 sents the sphere deformed into a sort of 



I 



irregular pear-shaped surface. The stalk 

 of the pear is in the southern part of Au- 

 stralia and contains Australasia and the 

 Antarctic continent. This is surrounded 

 on all sides but one (towards South Amer- 

 ica) by a zone of depression, the waist of 

 the pear. This, again, is surrounded on all 

 sides but one (towards Japan) by a zone of 

 elevation, the protuberant part of the pear ; 

 and finally we find the nose of the pear in 

 the central Atlantic between the Madeiras 

 and the Bermudas. I do not, however, 

 wish to emphasize the resemblance of the 

 surface to a pear or any other fruit, but 

 prefer to describe it as an harmonic 

 spheroid of the third degree. Another way 

 of regarding it would be as a surface with 

 ridges and furrows. From a place in the 

 South Atlantic there run three ridges : one 

 northwestwards across America, a second 

 northeastwards across Africa and Asia, and 

 the third southwards over the Antarctic 

 continent, continuing northwards across 

 Australia nearly to Japan. From the Sea 

 of Okhotsk there run three furrows: one 

 southwestwards across Japan, the Malay 

 Peninsula, and the Indian Ocean ; a second 

 southeastwards across the Pacific; and the 

 third northwards over the Arctic Ocean, 

 continuing southwards by way of the At- 

 lantic. Harmonies of the first and third 



degrees have in common the character of 

 giving depression at the antipodes of eleva- 

 tion; the harmonies of the second degree 

 give depression at the antipodes of depres- 

 sion and elevation at the antipodes of eleva- 

 tion. The maxima of the harmonics of the 

 first and third degrees are found to be 

 rather greater than the maximum of the 

 hannonic of the second degree. Of three 

 quantities to be added together the two 

 larger ones agree in giving depression at 

 the antipodes of elevation; a result which 

 is in accordance with the fact that most 

 continents have oceanic antipodes. 



When we superpose the effects i-epre- 

 sented by all the various harmonics of the 

 first, second and third degrees, so as to 

 make, as it were, a composite photograph 

 of all the various elevations and depres- 

 sions represented by them severally, each 

 in its appropriate amount as determined 

 by the harmonic analysis, we find the curve 



Fig. 14. 



shown in Fig. 14 as the theoretical curve of 

 separation between regions of elevation 

 and depression which are approximately 

 equal in area. I showed before a smoothed 

 curve (Fig. 3) which I proposed to take as 

 representing the facts to be accounted for. 

 The resemblance of the two curves seems to 

 be striking. Incidentally it has been 

 noticed how the prominent features of the 

 distribution of continent and ocean are 

 associated with the presence of various 

 harmonics. As regards the contour of the 

 great ocean basins, we seem to be justified 



