EARLY HISTORY OF GEOPHYSICS 3 
had been standardized by Dr. Pekar of the Edtvis Institute and to 
be instructed in their operation. The instruments were received in 
New York on September 5, 1922, and were in Houston in early No- 
vember. The first survey, one of the Spindletop salt dome, was made 
in early December, 1922. This was the first or one of the first surveys 
of an oil pool made by geophysical methods in the United States and 
appeared to be a brilliant success though it now seems, in the light 
of our more extensive knowledge of gravity variations, to have been 
in the nature of a lucky accident, since it was a very definite gravity 
maximum, one of the very few in the entire coastal regions. 
The method was apparently taken up by the petroleum companies 
in the early 1920s, first by the Anglo-Persian arid the Dutch-Shell 
groups. The Mexican Financier for January 1, 1922, contained an 
advertisement of the Eétvés balance and within the early months of 
the year the Dutch-Shell group was making a survey of the Hurgada 
field in Egypt, using Bamberg instruments. By the latter part of the 
year they were possibly being experimented with in California and a 
Dutch-Shell instrument was sent to the Gulf Coast about the time 
that the Amerada-Mexican Eagle instruments arrived and to Mexico 
within a very short time thereafter. 
With the apparently brilliant success of the initial survey in indi- 
cating Spindletop as a definite gravity maximum, surveys were ex- 
tended to other known domes, for the most part with vague and 
indifferent results. These experimental surveys generally covered only 
‘small areas’and were entirely inadequate to test the value of the 
instrument or of the method. Various prospects were surveyed with 
results none too definite and several of them were drilled and failed. 
«’ Just as we were about to abandon the instruments and method, a 
survey of the Nash area in southern Fort Bend County, Texas, gave 
a gravity maximum as brilliant and definite as that for Spindletop. 
A well was drilled in November, 1924, and encountered cap rock at 
648 feet and salt at 943 feet. This was the first successful geophysical 
prospect to be proved in the United States. Oil was discovered on the 
flank of this dome January 3, 1926, and this was probably the first 
oil pool to be discovered by geophysical methods in the entire world. 
During 1922, as consulting geologist to the Mexican Eagle Oil 
Company, I had recommended that the company make an attempt 
to locate the extensions of the buried Tomasopo ridge by the use of 
refraction seismic surveys. A German crew was engaged from Dr. L. 
Mintrop of the Seismos Company and it worked without very satis- 
247 
