14 Art. l.-T. Terada- 



Next, if a = a + hx, (11) 



c 



then 



h = --^Ji^ + hxy + 46^ 



if bja be small, we liave for large value of a- 



V (11') 



5. The above formula (7) — (10) may most plausibly be 

 applied to the case when long parallel strips of land and water 

 bounded by meridian lines are arranged alternately. For the 

 simplest case when the breadth of the strips are all equal, we may 

 assume provisionally 



a = a + h cos 



2-7:x (12) 



where a and b are constant, / is the breadth of the strip and x 

 denotes the longitude counted positive toward West. Then 



da 1- .. 1-x dv/. / 27r \-, %:x 



= — 6 Sill . = — 6 cos 





dx I I ' dx' \ I ' I ' 



Hence putting v2^ = /'>=2.t, we obtain 



Now suppose for very rougli approximation that the part of 

 Western Europe, the Atlantic Ocean and Northern America can 

 be compared with the ideal arrangement of land and water as 

 above considered, if we take the meridians 0°, 60°W. and 120°VV. 

 as the ideal coast lines, each strip of land or water having a breadth 

 of G0° in longitude. The comparison ma}^ in some measure be 

 justified, if Ave apply the above formula only to the narrow belt 



