The taser has proved a popular modern way to subdue a suspect, but in 1930s New York the men in blue were a little more shockingly hands-on in their approach.
In simpler times the mere presence of a home-built police scanner was lauded as a home course in law enforcement. But has Twitter killed the police radio star?
In an age when horses might still be found on Madison Avenue, electric and gas-powered cars battled for supremacy on the ad pages of the elite publications of the day.