A Yablochkov candle is a type of electric carbon arc lamp, invented in 1876 by Pavel Yablochkov. A Yablochkov candle consists of a sandwich of two long carbon blocks 6 by 12 millimetres in cross-section, separated by a block of inert material such as plaster of paris or kaolin. There is a small piece of fuse carbon paste linking the two carbon blocks at the top end; the assembly is mounted vertically into a suitable insulated holder. On application of the electric supply, the fuse strikes the arc; the arc continues to burn consuming the carbon electrodes as it does so. The first candles were powered by a Gramme machine. Electrodes last about two hours or until the power is cut. A classic Yablochkov candle cannot be relit, since the fuse wire between the electrodes has been consumed. Versions of the candle, included powdered metal in the inert separator; this would act as a new fuse wire. The advantage of the design over other carbon arc designs is that it removes the need for a mechanical regulator to maintain the appropriate distance between the carbon blocks to sustain the arc.
It was first demonstrated as street and theatre illumination during the Paris Exhibition of 1878, notably on the Avenue de l'Opéra. The candles were enclosed in globes of enamelled glass, with four to twelve candles in each connected in series. List of light sources List of Russian inventions Firecracker welding
Human zoos called ethnological expositions, were 19th-, 20th-, 21st-century public exhibitions of humans in a so-called natural or primitive state. The displays emphasized the cultural differences between Europeans of Western civilization and non-European peoples or with other Europeans who practiced a lifestyle deemed more primitive; some of them placed indigenous populations in a continuum somewhere between the great apes and Europeans. Ethnological expositions are now seen as degrading and racist, depending on the show and individuals involved. In the late 19th century German ethnographic museums were an attempt at empirical study of human culture, they contained artifacts from cultures around the world organized by continent allowing visitors to see the similarities and differences between the groups and form their own ideas. The ethnographic museums of Germany were explicitly designed to steer away from projecting certain principles or instructing its viewers to interpret the material in a particular manner.
They were instead left open for museum guests to form their own opinions. The directors of Germany's ethnographic museums intended to create a unifying history of mankind, to show how humans had progressed to the cosmopolitan creatures that walked the halls of these museums. Imperialism influenced the supporters and collectors of these museums, the displays and political rhetoric. Ethnology studies in Germany took a new approach in the 1870s as human displays were incorporated into zoos; these exhibits were lauded as educational to the general population by the scientific community of the time, because they were informing of the way people lived across the world. The exhibits were used as a way to show that Europeans had evolved into a superior cosmopolitan life; as Ethnogenic expositions were discontinued in Germany around 1931, there were many repercussions for the performers. Many of the people brought from their homelands to work in the exhibits had created families in Germany, there were many children, born in Germany.
Once they no longer worked in the zoos or for performance acts these people were stuck living in Germany where they had no rights and were harshly discriminated against. During the rise of the Nazi party the foreign actors in these stage shows were able to stay out of concentration camps because there were so few of them that the Nazis did not see them as a real threat. Although they were able to avoid concentration camps, they were not able to participate in German life as citizens of ethnically German origin could; the Hitler Youth did not allow children of foreign parents to participate, adults were rejected as German soldiers. Many ended up working in foreign laborer camps. After WWII ended, racism in Germany did not go away. Many people of foreign descent intended to leave after the war, but because of their German nationality, it was difficult for them to emigrate. Carl Hagenbeck was a German exotic animal businessman, who became famous for his conquering of the animal trade market during the mid to late 1800’s.
Due to the costs of acquiring and keeping animals, the financial implications started to worry Hagenbeck, he began looking for other ways to alleviate the company’s monetary strains. Heinrich Leutemann, an old friend of Hagenbeck suggested bringing along the people from the foreign lands to accompany the animals; the idea struck Hagenbeck as brilliant and he had a group of Laplanders accompany his next shipment of Reindeer. They went about their business as usual on the Hagenbeck property; the display was so successful. Although the concept of parading peoples captured from conquered lands goes back to the Romans, Hagenbeck claimed to have the first shows displaying “cultures” from foreign lands. Carl Hagenbeck continued to bring indigenous people along with the animals he was importing from across the globe; the people would come with their hunting equipment and other facets of their daily life. Hagenbeck's displays evolved in complexity. In 1876 Hagenbeck had a group of 6 Sami accompany a herd of reindeer, by 1874 his acts included close to 67 men and children in his Ceylon show performing with 25 elephants.
The performances expanded from showing every day activities such as milking reindeer and building huts, to displaying some of the more extravagant parts of the cultures such as magicians and devil dancers. The notion of the human curiosity has a history at least as long as colonialism. For instance, in the Western Hemisphere, one of the earliest-known zoos, that of Moctezuma in Mexico, consisted not only of a vast collection of animals, but exhibited humans, for example, dwarves and hunchbacks. During the Renaissance, the Medici developed a large menagerie in the Vatican. In the 16th century, Cardinal Hippolytus Medici had a collection of people of different races as well as exotic animals, he is reported as speaking over twenty languages. One of the first modern public human exhibitions was P. T. Barnum's exhibition of Joice Heth on February 25, 1835 and, the Siamese twins Chang and Eng Bunker; these exhibitions were common in freak show Another famous example was that of Saartjie Baartman of the Namaqua referred to as the Hottentot Venus, displayed in London and France until her death in 1815.
During the 1850s, Maximo and Bartola, two microcephalic children from El Salvador, were exhibited in the US and Europe under the names Aztec Children and Aztec Lilliputians. However, human
Queensland is the second-largest and third-most populous state in the Commonwealth of Australia. Situated in the north-east of the country, it is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south respectively. To the east, Queensland is bordered by the Coral Pacific Ocean. To its north is the Torres Strait, with Papua New Guinea located less than 200 km across it from the mainland; the state is the world's sixth-largest sub-national entity, with an area of 1,852,642 square kilometres. As of 15 May 2018, Queensland has a population of 5,000,000, concentrated along the coast and in the state's South East; the capital and largest city in the state is Australia's third-largest city. Referred to as the "Sunshine State", Queensland is home to 10 of Australia's 30 largest cities and is the nation's third-largest economy. Tourism in the state, fuelled by its warm tropical climate, is a major industry. Queensland was first inhabited by Torres Strait Islanders.
The first European to land in Queensland was Dutch navigator Willem Janszoon in 1606, who explored the west coast of the Cape York Peninsula near present-day Weipa. In 1770, Lieutenant James Cook claimed the east coast of Australia for the Kingdom of Great Britain; the colony of New South Wales was founded in 1788 by Governor Arthur Phillip at Sydney. Queensland was explored in subsequent decades until the establishment of a penal colony at Brisbane in 1824 by John Oxley. Penal transportation ceased in 1839 and free settlement was allowed from 1842; the state was named in honour of Queen Victoria, who on 6 June 1859 signed Letters Patent separating the colony from New South Wales. Queensland Day is celebrated annually statewide on 6 June. Queensland was one of the six colonies which became the founding states of Australia with federation on 1 January 1901; the history of Queensland spans thousands of years, encompassing both a lengthy indigenous presence, as well as the eventful times of post-European settlement.
The north-eastern Australian region was explored by Dutch and French navigators before being encountered by Lieutenant James Cook in 1770. The state has witnessed frontier warfare between European settlers and Indigenous inhabitants, as well as the exploitation of cheap Kanaka labour sourced from the South Pacific through a form of forced recruitment known at the time as "blackbirding"; the Australian Labor Party has its origin as a formal organisation in Queensland and the town of Barcaldine is the symbolic birthplace of the party. June 2009 marked the 150th anniversary of its creation as a separate colony from New South Wales. A rare record of early settler life in north Queensland can be seen in a set of ten photographic glass plates taken in the 1860s by Richard Daintree, in the collection of the National Museum of Australia; the Aboriginal occupation of Queensland is thought to predate 50,000 BC via boat or land bridge across Torres Strait, became divided into over 90 different language groups.
During the last ice age Queensland's landscape became more arid and desolate, making food and other supplies scarce. This led to the world's first seed-grinding technology. Warming again made the land hospitable, which brought high rainfall along the eastern coast, stimulating the growth of the state's tropical rainforests. In February 1606, Dutch navigator Willem Janszoon landed near the site of what is now Weipa, on the western shore of Cape York; this was the first recorded landing of a European in Australia, it marked the first reported contact between European and Aboriginal Australian people. The region was explored by French and Spanish explorers prior to the arrival of Lieutenant James Cook in 1770. Cook claimed the east coast under instruction from King George III of the United Kingdom on 22 August 1770 at Possession Island, naming Eastern Australia, including Queensland,'New South Wales'; the Aboriginal population declined after a smallpox epidemic during the late 18th century. In 1823, John Oxley, a British explorer, sailed north from what is now Sydney to scout possible penal colony sites in Gladstone and Moreton Bay.
At Moreton Bay, he found the Brisbane River. He established a settlement at what is now Redcliffe; the settlement known as Edenglassie, was transferred to the current location of the Brisbane city centre. Edmund Lockyer discovered outcrops of coal along the banks of the upper Brisbane River in 1825. In 1839 transportation of convicts was ceased, culminating in the closure of the Brisbane penal settlement. In 1842 free settlement was permitted. In 1847, the Port of Maryborough was opened as a wool port; the first free immigrant ship to arrive in Moreton Bay was the Artemisia, in 1848. In 1857, Queensland's first lighthouse was built at Cape Moreton. A war, sometimes called a "war of extermination", erupted between Aborigines and settlers in colonial Queensland; the Frontier War was notable for being the most bloody in Australia due to Queensland's larger pre-contact indigenous population when compared to the other Australian colonies. About 1,500 European settlers and their alli
Indigenous peoples known as first peoples, aboriginal peoples or native peoples, are ethnic groups who are the original settlers of a given region, in contrast to groups that have settled, occupied or colonized the area more recently. Groups are described as indigenous when they maintain traditions or other aspects of an early culture, associated with a given region. Not all indigenous peoples share this characteristic, as many have adopted substantial elements of a colonizing culture, such as dress, religion or language. Indigenous peoples may be settled in a given region or exhibit a nomadic lifestyle across a large territory, but they are historically associated with a specific territory on which they depend. Indigenous societies are found in every inhabited climate continent of the world. Since indigenous peoples are faced with threats to their sovereignty, economic well-being and their access to the resources on which their cultures depend, political rights have been set forth in international law by international organizations such as the United Nations, the International Labour Organization and the World Bank.
The United Nations has issued a Declaration on the Rights of Indigenous Peoples to guide member-state national policies to the collective rights of indigenous peoples, such as culture, identity and access to employment, health and natural resources. Estimates put the total population of indigenous peoples from 220 million to 350 million. International Day of the World's Indigenous Peoples is celebrated on 9 August each year; the adjective indigenous was used to describe animals and plant origins. During the late twentieth century, the term Indigenous people began to be used to describe a legal category in indigenous law created in international and national legislations, it is derived from the Latin word indigena, based on the root gen-'to be born' with an archaic form of the prefix in'in'. Notably, the origins of the term indigenous is not related in any way to the origins of the term Indian which until was applied to indigenous peoples of the Americas. Any given people, ethnic group or community may be described as indigenous in reference to some particular region or location that they see as their traditional indigenous land claim.
Other terms used to refer to indigenous populations are aboriginal, original, or first. The use of the term peoples in association with the indigenous is derived from the 19th century anthropological and ethnographic disciplines that Merriam-Webster Dictionary defines as "a body of persons that are united by a common culture, tradition, or sense of kinship, which have common language and beliefs, constitute a politically organized group". James Anaya, former Special Rapporteur on the Rights of Indigenous Peoples, has defined indigenous peoples as "living descendants of pre-invasion inhabitants of lands now dominated by others, they are culturally distinct groups that find themselves engulfed by other settler societies born of forces of empire and conquest". They form at present non-dominant sectors of society and are determined to preserve and transmit to future generations their ancestral territories, their ethnic identity, as the basis of their continued existence as peoples, in accordance with their own cultural patterns, social institutions and legal system.
The International Day of the World's Indigenous People falls on 9 August as this was the date of the first meeting in 1982 of the United Nations Working Group of Indigenous Populations of the Subcommission on Prevention of Discrimination and Protection of Minorities of the Commission on Human Rights. Throughout history, different states designate the groups within their boundaries that are recognized as indigenous peoples according to international or national legislation by different terms. Indigenous people include people indigenous based on their descent from populations that inhabited the country when non-indigenous religions and cultures arrived—or at the establishment of present state boundaries—who retain some or all of their own social, economic and political institutions, but who may have been displaced from their traditional domains or who may have resettled outside their ancestral domains; the status of the indigenous groups in the subjugated relationship can be characterized in most instances as an marginalized, isolated or minimally participative one, in comparison to majority groups or the nation-state as a whole.
Their ability to influence and participate in the external policies that may exercise jurisdiction over their traditional lands and practices is frequently limited. This situation can persist in the case where the indigenous population outnumbers that of the other inhabitants of the region or state. In a ground-breaking 1997 decision involving the Ainu people of Japan, the Japanese courts recognised their claim in law, stating that "If one minority group lived in an area prior to being ruled over by a majority group and preserved its distinct ethnic culture after being ruled over by the majority group, while another came to live in an area ruled over by a majority after consenting to the majority rule, it must be recognised that it is only natural that the distinct ethnic culture of the former group requires greater consideration."In Russia, definition of "indigenous peoples" is contested referring to a number of population (less
Thomas Alva Edison was an American inventor and businessman, described as America's greatest inventor. He is credited with developing many devices in fields such as electric power generation, mass communication, sound recording, motion pictures; these inventions, which include the phonograph, the motion picture camera, the long-lasting, practical electric light bulb, had a widespread impact on the modern industrialized world. He was one of the first inventors to apply the principles of mass production and teamwork to the process of invention, working with many researchers and employees, he is credited with establishing the first industrial research laboratory. Edison was raised in the American Midwest and early in his career he worked as a telegraph operator, which inspired some of his earliest inventions. In 1876, he established his first laboratory facility in Menlo Park, New Jersey, where many of his early inventions would be developed, he would establish a botanic laboratory in Fort Myers, Florida in collaboration with businessmen Henry Ford and Harvey Firestone, a laboratory in West Orange, New Jersey that featured the world's first film studio, the Black Maria.
He was a prolific inventor, holding 1,093 US patents in his name, as well as patents in other countries. Edison fathered six children, he died in 1931 of complications of diabetes. Thomas Edison was born, in 1847, in Milan and grew up in Port Huron, Michigan, he was the last child of Samuel Ogden Edison Jr. and Nancy Matthews Elliott. His father, the son of a Loyalist refugee, had moved as a boy with the family from Nova Scotia, settling in southwestern Ontario, in a village known as Shrewsbury Vienna, by 1811. Samuel Jr. fled Ontario, because he took part in the unsuccessful Mackenzie Rebellion of 1837. His father, Samuel Sr. had earlier fought in the War of 1812 as captain of the First Middlesex Regiment. By contrast, Samuel Jr.'s struggle found him on the losing side, he crossed into the United States at Sarnia-Port Huron. Once across the border, he found his way to Ohio, his patrilineal family line was Dutch by way of New Jersey. Much of his education came from reading R. G. Parker's The Cooper Union for the Advancement of Science and Art.
Edison developed hearing problems at an early age. The cause of his deafness has been attributed to a bout of scarlet fever during childhood and recurring untreated middle-ear infections. Around the middle of his career, Edison attributed the hearing impairment to being struck on the ears by a train conductor when his chemical laboratory in a boxcar caught fire and he was thrown off the train in Smiths Creek, along with his apparatus and chemicals. In his years, he modified the story to say the injury occurred when the conductor, in helping him onto a moving train, lifted him by the ears. Edison's family moved to Port Huron, Michigan after the canal owners kept the railroad out of Milan Ohio in 1854 and business declined. Edison sold candy and newspapers on trains running from Port Huron to Detroit, sold vegetables, he became a telegraph operator after he saved three-year-old Jimmie MacKenzie from being struck by a runaway train. Jimmie's father, station agent J. U. MacKenzie of Mount Clemens, was so grateful that he trained Edison as a telegraph operator.
Edison's first telegraphy job away from Port Huron was at Stratford Junction, Ontario, on the Grand Trunk Railway. He was held responsible for a near collision, he studied qualitative analysis and conducted chemical experiments on the train until he left the job. Edison obtained the exclusive right to sell newspapers on the road, with the aid of four assistants, he set in type and printed the Grand Trunk Herald, which he sold with his other papers; this began Edison's long streak of entrepreneurial ventures, as he discovered his talents as a businessman. These talents led him to found 14 companies, including General Electric, still one of the largest publicly traded companies in the world. In 1866, at the age of 19, Edison moved to Louisville, where, as an employee of Western Union, he worked the Associated Press bureau news wire. Edison requested the night shift, which allowed him plenty of time to spend at his two favorite pastimes—reading and experimenting; the latter pre-occupation cost him his job.
One night in 1867, he was working with a lead–acid battery when he spilled sulfuric acid onto the floor. It ran onto his boss's desk below; the next morning Edison was fired. His first patent was for the electric vote recorder, U. S. Patent 90,646, granted on June 1, 1869. Finding little demand for the machine, Edison moved to New York City shortly thereafter. One of his mentors during those early years was a fellow telegrapher and inventor named Franklin Leonard Pope, who allowed the impoverished youth to live and work in the basement of his Elizabeth, New Jersey, while Edison worked for Samuel Laws at the Gold Indicator Company. Pope and Edison founded their own company in October 1869, working as electrical engineers and inventors. Edison began developing a multiplex telegraphic system, which could send two messages in 1874. Edison's major innovation was the establishment of an industrial research lab in 1876, it was built in Menlo Park, a part of Raritan Township in Middlesex County, New Jersey, with the funds from the sale of Edison's qua
16th arrondissement of Paris
The 16th arrondissement of Paris is one of the 20 arrondissements of the capital city of France. In spoken French, this arrondissement is referred to as seizième; the arrondissement includes part of the Arc de Triomphe, a concentration of museums between the Place du Trocadéro and the Place d'Iéna, complemented in 2014 by the Fondation Louis Vuitton. With its ornate 19th-century buildings, large avenues, prestigious schools and various parks, the arrondissement has long been known as one of French high society's favourite places of residence to such an extent that the phrase le 16e has been associated with great wealth in French popular culture. Indeed, the 16th arrondissement of Paris is France's third richest district for average household income, following the 7th, Neuilly-sur-Seine, both adjacent; the 16th arrondissement hosts several large sporting venues, including: the Parc des Princes, the stadium where Paris Saint-Germain football club plays its home matches. The Bois de Boulogne, the second-largest public park in Paris, is located in this arrondissement.
The land area of this arrondissement is 16.305 km2 more than half of which consists of the Bois de Boulogne park. Excluding the Bois de Boulogne, its land area is 7.846 km2. It is the largest arrondissement in Paris in terms of land area; the 16th arrondissement population peaked in 1962. At the last census, the population was 169,372; the 16th arrondissement contains a great deal of business activity. The 16th arrondissement is thought to be one of the richest parts of Paris, features some of the most expensive real estate in France including the famous Auteuil "villas", heirs to 19th century high society country houses, they are exclusive gated communities with huge houses surrounded by gardens, rare in Paris, it is the only arrondissement in Paris to be divided into two separate postal codes. The southern part of the arrondissement carries a postal code of 75016, while the northern part has the code of 75116. Four Fortune Global 500 have their head offices in this arrondissement: PSA Peugeot Citroën, Kering and Veolia.
In addition Lagardère and Technip have their headquarters in this arrondissement. At one time Aérospatiale had its head office in the arrondissement. In one of the opening scenes of the 1965 James Bond film Thunderball, character Emilio Largo is seen arriving at the headquarters of The International Brotherhood for the Assistance of Stateless Persons; this scene was shot on Avenue d'Eylau in the 16th arrondissement. The controversial 1972 film Last Tango in Paris, starring Marlon Brando and Maria Schneider, was filmed at various locations in the 16th arrondissement, with the apartment the characters stayed in being located in Passy. A notorious serial murder case, which generated an international media circus, centered in the 16th arrondissement during the Nazi occupation of France during World War II; the focal point of the case was French doctor Marcel Petiot, who in 1941 bought a house at 21 Rue le Sueur in "the heart of Paris's fashionable 16th arrondissement". On 11 March 1944, Petiot's neighbors complained to police of a foul stench in the area and of large amounts of smoke billowing from a chimney of the house.
Fearing a chimney fire, the police summoned firemen, who entered the house and found a roaring fire in a coal stove in the basement. In the fire, scattered in the basement, were human remains. Following an investigation, during which time Petiot attempted to evade capture, "the monster of rue Le Sueur" was arrested and went on trial on 19 March 1946, facing 135 criminal charges, he was sentenced to death. On 25 May, Petiot was beheaded, after a stay of several days due to a problem in the release mechanism of the guillotine. Here is a list of domestic French sixth-form colleges/high schools in the arrondissement Lycée Saint-Jean de Passy Lycée Saint-Louis-de-Gonzague Lycée Janson de Sailly Lycée Claude Bernard Lycée Jean-Baptiste-Say Lycée Gerson Lycée Molière Lycée La Fontaine Lycée Octave-Feuillet Lycée Notre-Dame des Oiseaux École Pascale Institut de l'Assomption Institut de La Tour Lycée René-Cassin École normale israélite orientale Établissement Gerson Cours privé Beauséjour École d'esthétique Yves Rocher Ipécom Paris Lycée Moria-Diane Benvenuti Lycée Notre-Dame des Oiseaux Lycée Passy-Saint-Honoré Lycée Sainte-ThérèseInternational schools: Russian Embassy School of Paris, on the grounds of the Russian Embassy in Paris.
Colegio Español Fecerico García Lorca, a Spanish international primary school owned by the Spanish government The Spanish secondary school, Liceo Español Luis Buñuel, is located in Neuilly sur Seine. The two campuses of the International School of Paris Kingsworth International School The Université Paris-Dauphine is in the arrondissement, as well as Paris Institute of Technology, part of Paris Descartes University, one of Paris biggest public universities; the renowned "classes préparatoires" establishment Intégrale: Institut d'enseignement supérieur privé have one of their campuses in the arrondissement. The École de langue japonaise de Paris, a supplementary Japanese education programme, is held at the École Maternelle et Primaire Saint Francois d'Eylau in the 16th arrondissement; the school has its offices at the Associatio
A megaphone, speaking-trumpet, blowhorn, or loudhailer is a portable or hand-held, cone-shaped acoustic horn used to amplify a person’s voice or other sounds and direct it in a given direction. The sound is introduced into the narrow end of the megaphone, by holding it up to the face and speaking into it, the sound waves radiate out the wide end. A megaphone increases the volume of sound by increasing the acoustic impedance seen by the vocal cords, matching the impedance of the vocal cords to the air, so that more sound power is radiated, it serves to direct the sound waves in the direction the horn is pointing. It somewhat distorts the sound of the voice because the frequency response of the megaphone is greater at higher sound frequencies. Since the 1960s the voice-powered acoustic megaphone described above has been replaced by the electric megaphone, which uses electric power and a folded horn to amplify the voice; the initial inventor of the speaking trumpet is a subject of historical controversy.
There have been references to speakers in Ancient Greece wearing masks with cones protruding from the mouth in order to amplify their voices in theatres. Hellenic architects may have consciously utilized acoustic physics in their design of theatre amphitheaters. A drawing by Louis Nicolas on page 14 of the Codex canadensis, circa 1675 to 1682, shows a Native American chief named Iscouakité using a megaphone made of birch bark; the text of the illustration says. Both Samuel Morland and Athanasius Kircher have been credited with inventing megaphones around the same time in the 17th century. Morland, in a work published in 1655, wrote about his experimentation with different horns, his largest megaphone consisted of over 20 feet of copper tube and could project a person's voice a mile and a half. Twenty years earlier, Kircher described a device that could be used as both a megaphone and for "overhearing" people speaking outside a house, his coiled horn would be mounted into the side of a building, with a narrow end inside that could be either spoken into or listened to, the wide mouth projecting through the outside wall.
Morland favored a tube-shaped speaking device. Kircher’s horn, on the other hand, utilized a “cochleate” design, where the horn was twisted and coiled to make it more compact. A papier-mache trumpet of special design was the Sengerphone. Additionally, in ruins of Tiwanaku are stones around the central place with holes shaped in megaphone's profile, their purpose is today unknown, but as local guards can show, it is possible to amplify human voice as it is loud enough to hear it across large area. The term ‘megaphone’ was first associated with Thomas Edison’s instrument 200 years later. In 1878, Edison developed a device similar to the speaking trumpet in hopes of benefiting the deaf and hard of hearing, his variation included three separate funnels lined up in a row. The two outer funnels, which were six feet and eight inches long, were made of paper and connected to a tube inserted in each ear; the middle funnel was similar to Morland’s speaking trumpet, but had a larger slot to insert a user’s mouth.
With Edison’s megaphone, a low whisper could be heard a thousand feet away, while a normal tone of voice could be heard two miles away. On the listening end, the receiver could hear a low whisper at a thousand feet away; however the apparatus was much too large to be portable. George Prescott wrote: “The principal drawback at present is the large size of the apparatus.” Since the 1960s acoustic megaphones have been replaced by electric versions, although the cheap, rugged acoustic megaphone is still used in a few venues, like cheering at sporting events and cheerleading, by lifeguards at pools and beaches where the moisture could damage the electronics of electric megaphones. An electric megaphone is a handheld public address system, an electronic device that amplifies the human voice like an acoustic megaphone, using electric power, it consists of a microphone to convert sound waves into an electrical audio signal, an amplifier powered by a battery to increase the power of the audio signal, a loudspeaker to convert the audio signal to sound waves again.
Although heavier than acoustic megaphones, electric megaphones can amplify the voice to a higher level, to over 90 dB. They have replaced acoustic megaphones in most applications, are used to address congregations of people wherever stationary public address systems are not available. Although electronic public address systems have existed since vacuum tube amplifiers were developed in the early 1920s, vacuum tube versions were too heavy to be portable. Practical portable electric megaphones had to await the development of microelectronics which followed the invention of the transistor in 1947. In 1954, TOA Corporation developed the world's first transistorized megaphone. Handheld versions are shaped like the old acoustic megaphone, with a microphone at one end and a horn speaker at the other, a pistol grip on the side, with a trigger switch to turn it on. In use, the device is held up to the mouth, the trigger is pressed to turn it on while speaking. Other larger versions hang from the shoulder on a strap, have a separate handheld microphone on a cord to speak into, so users can address a crowd without the instrument obscuring their faces.
A vast array of modern electric megaphones are available to purchase, characteristics like power, weight and the presence of alarms and shoulder straps all contribute to a consumer’s choice. The shape of the megaphone