Measurements of the Differences of Gravity between the Coast and Geodetic Survey (C & GS), the National Bureau of Standards (NBS), Washington, D.C., and the Geographical Survey Institute (GSI), Chiba, Japan.

Abstract

Acting on Resolution VII adopted at the meeting of the International Gravimetric Commission at Paris in 1953, measurements of the differences of gravity between C&GS, NBS and GSI were carried out by members of the Geographical Survey Institute. The differences of the accelerations due to gravity were:
gc&GS-gGSI=+329.8±0.3 (m.e.) mgal
gNBS-gGSI=+310.4±0.3 (m.e.) mgal
The result leads to a conclusion; the difference between the present value of gc&GS-gGSI=+328.2 mgal and the above-mentioned is + 1.6 mgal, while that between the present value of gNBs-gust=+310.2 mgal and the above-mentioned is+0.2 mgal.
In the former case the difference is somewhat too large. According to the personal information from Mr. Rice of the Coast and Geodetic Survey, however, the results of recent relative measurements between C&GS and NBS, obtained by member of the Coast and Geodetic Survey using a Worden gravimeter, showed that the new value of gravity at Commerce Base relative to gNBs (980.100) was almost one milligal high. If this value is used for our relative measurements instead of gc&Gs (980.118), the difference gc&GS-gGSI will be much more closely coincided.
In the latter case, the difference is far smaller than might have been anticipated from the accuracy of the procedure used by E. Borrass for his first determination of the present value gTOKYO (979.801), to which the adopted value gGSI is refered.