Continental drift plate tectonics theory. In particular, the English geologist Arthur Holmes proposed in 1920 that plate junctions might lie beneath the sea, and in 1928 that convection currents within the mantle might be the driving force. Holmes' views were particularly influential: in his bestselling textbook, "Principles of Physical Geology," he included a chapter on continental drift, proposing that Earth's mantle contained convection cells which dissipated radioactive heat and moved the crust at the surface. Holmes' proposal resolved the phase disequilibrium objection (the underlying fluid was kept from solidifying by radioactive heating from the core). However, scientific communication in the '30 and
One-name study the etymology, meaning and geographic origin of names, also draw on the macro perspective provided by a one-name study. Many people conducting family history, genealogical or onomastic research may conduct a one-name study of a surname in a given period or locality quite informally. A full one-name study can be daunting, particularly if the surname is very common. Conversely, a rare surname can be difficult to trace. Since such studies are usually conducted by individuals as a pastime, they are generally feasible only when a surname is not used by more than a couple of thousand contemporary people, so that