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Hello Central! / photographed and published by B.W. Kilburn, Littleton, N.H.

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Hello Central! / photographed and published by B.W. Kilburn, Littleton, N.H.

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Summary

Girl holding doll and making telephone call.
12968 U.S. Copyright Office.
No. 12857.

Stereographs are devices capable of building a three-dimensional​ image out of two photographs that have about two and a half inches difference between them so that it could imitate the two eyes’ real field of view. Combining these images into a single one with the help of stereoscope, a person can experience the illusion of the image’s depth. Stereoscope uses the same principle as in human binocular vision. Our eyes are separated by about two inches, so we see everything from two different angles. When the brain combined those views in a single picture, we get the spatial depth and dimension. Stereographs were extremely popular between 1850 and 1930 all around the world. Millions of stereographs were made during that time. There was a broad range of themes: landscape, travel, historical moments, nature disasters, architecture and many others. Nowadays, simply launch this collection full screen and put your mobile device in Google Cardboard Viewer.

The invention of the telephone still remains a confusing morass of claims and counterclaims, which were not clarified by the huge mass of lawsuits to resolve the patent claims of commercial competitors. The Bell and Edison patents, however, dominated telephone technology and were upheld by court decisions in the United States. Bell has most often been credited as the inventor of the first practical telephone. Alexander Graham Bell was the first to patent the telephone as an "apparatus for transmitting vocal or other sounds telegraphically". The telephone exchange was an idea of the Hungarian engineer Tivadar Puskás (1844 - 1893) in 1876, while he was working for Thomas Edison on a telegraph exchange. Before the invention of the telephone switchboard, pairs of telephones were connected directly with each other, practically functioned as an intercom. Although telephones devices were in use before the invention of the telephone exchange, their success and economical operation would have been impossible with the schema and structure of the contemporary telegraph systems. A telephone exchange was operated manually by operators, or automatically by machine switching. It interconnects individual phone lines to make calls between them. The first commercial telephone exchange was opened at New Haven, Connecticut, with 21 subscribers on 28 January 1878, in a storefront of the Boardman Building in New Haven, Connecticut. George W. Coy designed and built the world's first switchboard for commercial use. The District Telephone Company of New Haven went into operation with only twenty-one subscribers, who paid $1.50 per month, a one-night price for a room in a city-center hotel. Coy was inspired by Alexander Graham Bell's lecture at the Skiff Opera House in New Haven on 27 April 1877. In Bell's lecture, during which a three-way telephone connection with Hartford and Middletown, Connecticut, was demonstrated, he first discussed the idea of a telephone exchange for the conduct of business and trade.

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Date

01/01/1899
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Contributors

B.W. Kilburn Company.
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Source

Library of Congress
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Copyright info

No known restrictions on publication.

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children using telephones
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