3G CAPTAIN E. W. CREAK. 



Disturbances from the Normal. 



In Table I. the disturbances from the normal are given, the force being expressed 

 in tenns of C.G.S. units = 0-00001. 



These results form the elements from which the Charts 1, 2, 3, 4 (p. 34) are compiled. 



Commencing with the disturbances of the declination on Chart 1, it will be 

 observed that principal disturbance occurs at station I, towards the western side 

 of the lagoon amounting to 1Q', the needle being deflected to the westward. 



Again, there is a belt of little or no disturbance more nearh' defined by the black 

 I'idge line extending across the east and west axis of the atoll. 



The wliole field of disturbance of this element in the north and south direction 

 appears to extend from to about 11 miles north of the lidge line and 14 miles to 

 south of it ; to the eastward and westward of the atoll the field is indeterminate for 

 want of observation. 



On the whole, the chart of the declination disturbances may be considered as 

 accurate, the observations over the lagoon having been carefully taken on board the 

 ship, which gave a steady platform. The observations on land were further corrected 

 for the diurnal variation. 



Turning to the vertical force disturbances on Chart 4, the greatest values observed 

 occur at C, D and A, taking them in order of values. 



Taking next the direction of the ariows in the lagoon showing the direction and 

 amount of the horizontal disturbance, it will be seen that they point to the origin 

 of the principal disturbances as being due to at least two centres ot force situated 

 below the ridge line. 



It will be remarked that the principal foci ot disturbance at C, D, A, bear 

 the plus sign, denoting that the north seeking end of the needle is drawn down- 

 wards, and also from the surrounding values of the same sign that the amount of 

 disturbance of that nature is far in excess of that repelling the needle as shown by 

 values bearing the minus sign. 



This is the more remarkable, as heretofore observation has generally shown that 

 in islands situated in regions of minus vertical force the reverse order has been the 

 rule, and minus vertical force disturbances have largely exceeded those with the 

 plus sign. 



Charts 2 and 3 showing lines of equal disturbance of the inclination and horizontal 

 force do not require any special remarks. 



Before concluding this account of the dist\u^bances, it is necessary to point out 

 that although we may accept the observations on land at Funafuti Atoll as trust- 

 worthy, those of the inclination and force at the lagoon stations are much less so, 

 having been taken on a raft in motion and with relative instruments. The general 

 features of the disturbances may, liowever, be accepted as correct. 



The regions of greatest disturbance were duly communicated to Professor David 



