CONTENTS 
Some aS ae of Electrical a ads eras in Locating Oil Structures 
LrEo J. PETERS AND JOHN BARDEEN 
New Instrument for Measuring Very Small Differences in Gravity 
KENNETH HARTLEY 
Charts for Torsion Balance Readings. ....... . M.M.SLOTNICK 
Effects of Heat Treatment on Fine Metallic Suspensions. . . N. N. ZIRBEL 
On the Correlation of eg aaa Surfaces with the Rock Strata . 
; ; ; AEN ye ~C. E. Van OrsTRAND 
Geothermal Gradient Determinations in the Lake ee Copper Mines. 
eae . L.R. INGERSOLL 
aed of Elastic Waves in Granite . 
MUS Why tat ee Don LEET AND W. MAaurRICE Ewinc 
eee | of Sound omer in Stratified Formations 
_ Burton McCotium anv F. A. SNELL 
Calculation of the Motion of the Ground from Seismograms. H. A. WILSON 
72 
84 
14. 
