In their attempt to ensure white supremacy decades after emancipation, in the early 20th century, most southern states created laws based on the one-drop rule, defining as black, persons with any known African ancestry. This was a stricter interpretation than what had prevailed in the 19th century; it ignored the many mixed families in the state and went against commonly accepted social rules of judging a person by appearance and association. Some courts called it "the traceable amount rule." Anthropologists called it an example of a hypodescent rule, meaning that racially mixed persons were assigned the status of the socially subordinate group.
What was the rule in the 1800s called?
the traceable amount rule

Philosophy has become an increasingly academic discipline. More of its practitioners lament this situation than occurs with the sciences; nonetheless most new philosophical work appears in academic journals. Major philosophers through history—Plato, Aristotle, Socrates, Augustine, Descartes, Kierkegaard, Nietzsche—have become as canonical as any writers. Some recent philosophy works are argued to merit the title "literature", but much of it does not, and some areas, such as logic, have become extremely technical to a degree similar to that of mathematics.
What classic area of study is now mostly reserved for academic consideration?
Philosophy

In the US, one kilowatt-hour (3.6 MJ) of electricity currently causes an average 1.34 pounds (610 g) of CO
2 emission. Assuming the average light bulb is on for 10 hours a day, a 40-watt bulb will cause 196 pounds (89 kg) of CO
2 emission per year. The 6-watt LED equivalent will only cause 30 pounds (14 kg) of CO
2 over the same time span. A building’s carbon footprint from lighting can therefore be reduced by 85% by exchanging all incandescent bulbs for new LEDs if a building previously used only incandescent bulbs.
A 6-watt LED left on for 10 hours a day will emit how much CO 2?
30 pounds