GRAVITY DETERMINATIONS ON THE CARNEGIE 



77 



Table 3. Principal facts at Carnegie gravity stations 

 Values are based on Potsdam System 



Element 



Station 



At sea 



Penrhyn 



Pago Pago 



Latitude (<t>) 



Longitude (X) 



Depth, fathoms 



Observed gravity (g), cm/sec^ 



Corrections, cm/sec^ 

 Elevation 

 Topography and compensation 



Computed values, cm/sec^ 



HelmertL^J, theoretical Vq = Vo" f^J 



computed gravity (gc) 

 Bowie I'^J, theoretical Yq = yo" >■''] 



computed gravity (gc) 



Anomalies, cm/see^ 



Free air (g - yo")> Helmerti^] 



Bowie I '^ J 

 Isostatic (g - gc), Helmertl^] 



Bowie l^J 



27° 44'.8 N 



135° 22;i W 



2465 



979.197 



8° 59^7 S 

 158° 03'.8 W 

 130 

 978.453 



0.000 

 + 0.004 



0.000 

 + 0.248 



14° 16:6 S 



170° 41'.0 W 



10 



978.668 



0.000 

 + 0.205 



[a] Using Helmert formula of 1901, y^ = 978.030 (1 + 0.005302 sin2 - 0.000007 sin2 2<t>). W Sta- 

 tions being at sea level with no correction for elevation. [c] Using Bowie formula of 1917, Vg = 978.039 

 (1 + 0.005294 sin2 ((, - 0.000007 sin2 2(t>). 



investigation of the gravity field in the region of the 

 Tonga Deep doubtless would prove of great interest, 

 especially since there is a great deal of volcanic activ- 

 ity in this area. 



Thus the contribution in number of new gravity sta- 

 tions determined on board the Carnegie during the last 

 few months of her cruise is not great. It has been the 

 aim of this report of the first attempt to make accurate 

 determinations of gravity on board a sailing ship at sea, 

 to show that in spite of the difficulties inevitably encoun- 

 tered in any first attempt, and in spite of the writer's 

 lack of any previous experience with the apparatus, to- 

 gether with the fact that because of numerous other 

 duties he could devote only a small amount of his time 

 to this research, a few successful observations were 

 obtained. 



It is hoped that this report may succeed first in 

 stimulating further researches in gravity determinations 

 at sea, either aboard surface ships or aboard submarines, 

 and second in being of some assistance in their success. 



Acknowledgments 



Grateful appreciation is expressed to Dr. F. A. Ven- 

 ing Meinesz, whose personal interest and assistance 

 have made it possible to complete the Carnegie gravity 

 reductions, and to Captain R. S. Patton, Director of the 

 U. S. Coast and Geodetic Survey, through whose interest 

 and cooperation the isostatic reductions for the three 

 new Carnegie gravity stations were made by that bureau. 



