FOREWORD 
The Society of Exploration Geophysicists was organized early 
in 1930 but Vol. I, No. 1, of its present journal, GEOPHYSICS, is 
dated January, 1936. In the period between these dates, many 
geophysical papers were presented at the regular annual meet- 
ings held jointly with the meetings of the American Association 
of Petroleum Geologists and at occasional other meetings. These 
papers were published in various journals, including special geo- 
physical numbers of the Bulletin of the American Association of 
Petroleum Geologists, Physics, as “Special Papers” published in 
mimeograph form by the Society and in an earlier publication 
of the Society (before a change to its present name) which was 
called Journal of the Society of Petroleum Geophysicists. 
Since the appearance of the first number of GEOPHYSICS, 
the membership of the Society has increased approximately five- 
fold, which means that these earlier scattered publications have 
not been readily available to a large proportion of the present 
membership. These papers contain much of the early history and 
technical fundamentals of the present geophysical exploration 
industry. Therefore, the Executive Committee of the Society, at 
its last regular meeting, authorized the republication of these old 
papers into a single volume. It is hoped that they will be found 
of interest and value to the present members of the Society and 
other geophysicists throughout the world, and particularly to the 
younger members of the profession to whom this early work is 
largely unknown. 
Acknowledgment is made of permission granted by the Ameri- 
can Association of Petroleum Geologists and by the American 
Institute of Physics to reprint papers originally published in their 
journals. 
L. L. NETTLETON, Editor 
Geophysics (1945-1947) 
