Leason Adams

Geophysical work

His most enduring work began in 1919, when he was working at the Carnegie Institution for Science to develop new methods for high-pressure measurement. In the late 19th century the prevailing view of the Earth was that it was made up of a thin crust floating on a molten interior. By Adams' day, this view was being challenged, especially by the findings of some seismologists who had found the wave velocities of the Earth at different depths. Wave velocities depend upon the elastic constants of the materials through which they pass, in particular the bulk modulus and stiffness.

It should be possible to combine the experimentally-determined wave velocities of the various parts of the Earth's interior and the elasticity data from various rocks in order to find out about the Earth's interior. However, by the early 20th century no one had been able to determine the elastic constants of common rocks, because almost all rocks are slightly porous, complicating conventional elasticity measurement methods.

Adams was able to solve this problem by fashioning rocks into cylinders, putting thin hermetically sealed metal jackets around them, and subjecting them to high pressures while inside a mobile liquid in a pressure vessel. By recording the piston displacement required in order to achieve a given pressure, Adams could find the volume change of the rocks and their bulk modulus.