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 and group it geographically, approximately representing the different family groups. Others attempt to reconstruct lineages. In most one-name studies, a united lineage will not be discovered, but broad perspectives can be achieved, giving clues to name origins and migrations. Many researchers are motivated to go beyond the one-name-study stage and to compile fully researched, single-family histories of some of the families they discover. Accessibility of the data required for a one-name study varies from country to country. Where civil registration indexes are open to public search, they may not be online or gathered in the national capital, but are scattered