| 1930 |
The first jet engine is invented. |
| 1930 |
The first public television broadcast takes place in the United States. |
| 1930 |
The Oklahoma City Field produces 36.4 million barrels of oil, 4th largest of American fields. |
| 1930 |
Cities Service buys a bulk lubricants plant and warehouse in Chicago. |
| 1931 |
The Art Deco style Empire State Building is constructed in New York. |
| 1931 |
Cities Service becomes a billion dollar corporation with 25,000 employees. |
| 1932 |
Franklin D Roosevelt elected President of the United States. |
| 1933 |
Adolf Hitler named Chancellor of Germany. |
| 1934 |
Gunman and bandit John Dillinger shot and killed by federal agents outside a movie theatre. |
| 1935 |
Congress enacts the National Labor Relations Act (NLRA), which provided even stronger government support for organized labor. |
| 1935 |
W. Alton Jones, as Senior Vice President of Cities Service testifies against the Wheeler-Rayburn Bill (Public Utilities Act of 1935 which would break up the utility companies). |
| 1936 |
Jesse Owens, an African-American athlete competing for the United States, wins four gold medals in the track and field competition at the Berlin Olympics. |
| 1936 |
Cities Service marketing moves from Chicago to Tulsa. |
| 1936 |
At the close of the year Cities Service was comprised of 24 petroleum companies, 45 electric companies and 15 natural gas companies. |
| 1937 |
Henry L. Dougherty recognized with the Anthony Lucas Medal for "Distinguished Achievement for Improving the Technique of Finding and Producing Oil." |
| 1937 |
More than 50 feet long and 8 feet high, the first programmable calculator is built, the predecessor to the modern computer. |
| 1938 |
Chester Carlson develops an electronic dry copying process called xerography-the predecessor to today's copy machines. |
| 1939 |
Germany invades Poland, starting World War II. |
| 1939 |
RCA exhibits television to the public at the World's Fair in New York City. |
