Changes in Population

Radio Record, Volume III, Issue 33, 28 February 1930, Page 8

Changes in Population

Shown by Electricity AN interesting calculating machine is now in use at Census Headquarters of the United States, providing a constant and reliable estimate of the everechanging population, It is electrically-operated, a tiny light flashing each 13 seconds to indicate a birth, another every 23 seconds shows a death, and other flashes indicate the arrival of an immigrant, or the departure of an emigrant. A counter at the top of the chart gives an estimate of the total population of the nation at

any time.