A few nice model cars images I found:
Car horn
Image by . SantiMB .
Sitges, Garraf, Barcelona (Spain).
49 International Barcelona-Sitges Vintage Car Rally - Third and last part of the series.
Car horns date back to the earliest of horseless carriages. In the early 1800's, steam carriages were becoming popular in Britain. For the safety of pedestrians and animals, a law was passed stating that "…self-propelled vehicles on public roads must be preceded by a man on foot waving a red flag and blowing a horn.". Of course, it did not take long to realize that a horn in the automobile itself, operated by the driver, was much more efficient.
In the late 1800's motorists actually had their choice of several signaling devices including bulb horns, whistles, and bells. In America, most chose bells. Despite the noise made by these devices, they were considered a quieter alternative to the clatter of horses' hooves and the bouncing of metal carriage wheels on cobblestone. In the early 1900's the bulb horn, first introduced in France, became popular in America. Its sound was considered more novel and penetrating than the bell. By 1910 some people were calling for a more effective warning device, one that could be heard at least an eighth of a mile ahead. Manufacturers responded with a variety of whistles, chimes, sirens, and horns, some of which ran off exhaust gases. The Sireno, named after Greek mythological creatures who lured mariners to destruction with the irresistible charm of their song, was advertised as a "one-mile signal". Another device, called the Godin, was publicized with the slogan "You press as you steer and your pathway is clear.".
Source: www.cogapa.com/history.htm
This model of car horn is named "boa constrictor".
