He's increased his powers of scientific observation. His observation is empirical evidence. Empiricism relies on observation and experimentation.
Judaism, Christianity, and Islam
The factors that caused the Great Depression to spread around the world are:
Americans stopped buying from overseas nations
Many countries raised tariffs on imported goods
Americans demanded repayment of European loans
The Great Depression was the worst economic downturn in the history of the industrialized world, protracting from 1929 to 1939. It began following the crash of the stock market of October 1929, which sent Wall Street into a panic and wiped out millions of investors.
Prior the Great Depression, the Federal Reserve had caused banks to decrease their willingness to loan money to the people. the stock market also declined at the time before
The main idea of the quote is that the Soviets are tightening their contol over Cnetral and Eastern Europe. The other sentences complete that idea by letting us know what they are doing with Central and Eastern Europe.
