Amos Dolbear
Encyclopedia
Amos Emerson Dolbear was an American
physicist
and inventor. His patents interfered with Guglielmo Marconi
's planned activities in the U.S. Dolbear researched electrical spark conversion into sound waves and electrical impulses. He was a professor at University of Kentucky
in Lexington
from 1868 till 1874. In 1874 he became the chair of the physics department at Tufts University
in Medford, Massachusetts
.
, in Delaware, Ohio
. While a student at Ohio Wesleyan, he had made a "talking telegraph" and invented a receiver containing two features of the modern telephone: a permanent magnet and a metallic diaphragm that he made of a tintype
. He invented the first telephone receiver with a permanent magnet in 1865, 11 years before Alexander Graham Bell
patented his model. Later, Dolbear couldn't prove his claim, so Bell kept the patent. Dolbear lost his case before the U. S. Supreme Court, (Dolbear et al. v. American Bell Telephone Company). The June 18, 1881 edition of Scientific American reported:
In 1876, Dolbear patented a magneto electric telephone. He patents a static telephone in 1879.
In 1882 Professor A. E. Dolbear was able to communicate over a distance of a quarter of a mile without wires in the Earth. It is interesting to note that the Tufts Professor was ahead of Hertz and Marconi. He received a U.S. patent for a wireless telegraph in March of that year. His device relied on conduction in the ground, a type of radio transmission. His set-up used phones grounded by metal rods poked into the earth. His transmission range was at least as much as a half a mile and he received a patent for this device, , in 1886. But more importantly the Dolbear patent prevented the Marconi Company from operating in the United States. In the end Marconi had to purchase Dolbear's patent, primarily because it was:
In 1868 Dolbear (while a professor at Bethany College) invented the electrostatic telephone. He also invented the opeidoscope (an instrument for visualizing vibration of sound waves, using a mirror mounted on a membrane) and a system of incandescent lighting. He authored several books, articles, and pamphlets, and was recognized for his contributions to science at both the Paris Exposition in 1881 and the Crystal Palace Exposition in 1882.
In 1897, Dolbear published an article "The Cricket as a Thermometer" that noted the correlation between the ambient temperature and the rate at which cricket
s chirp. The formula expressed in that article became known as Dolbear's Law
.
Journal articles
Patents
General
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
physicist
Physicist
A physicist is a scientist who studies or practices physics. Physicists study a wide range of physical phenomena in many branches of physics spanning all length scales: from sub-atomic particles of which all ordinary matter is made to the behavior of the material Universe as a whole...
and inventor. His patents interfered with Guglielmo Marconi
Guglielmo Marconi
Guglielmo Marconi was an Italian inventor, known as the father of long distance radio transmission and for his development of Marconi's law and a radio telegraph system. Marconi is often credited as the inventor of radio, and indeed he shared the 1909 Nobel Prize in Physics with Karl Ferdinand...
's planned activities in the U.S. Dolbear researched electrical spark conversion into sound waves and electrical impulses. He was a professor at University of Kentucky
University of Kentucky
The University of Kentucky, also known as UK, is a public co-educational university and is one of the state's two land-grant universities, located in Lexington, Kentucky...
in Lexington
Lexington, Kentucky
Lexington is the second-largest city in Kentucky and the 63rd largest in the US. Known as the "Thoroughbred City" and the "Horse Capital of the World", it is located in the heart of Kentucky's Bluegrass region...
from 1868 till 1874. In 1874 he became the chair of the physics department at Tufts University
Tufts University
Tufts University is a private research university located in Medford/Somerville, near Boston, Massachusetts. It is organized into ten schools, including two undergraduate programs and eight graduate divisions, on four campuses in Massachusetts and on the eastern border of France...
in Medford, Massachusetts
Medford, Massachusetts
Medford is a city in Middlesex County, Massachusetts, in the United States, on the Mystic River, five miles northwest of downtown Boston. In the 2010 U.S. Census, Medford's population was 56,173...
.
Biography
Dolbear was a graduate of Ohio Wesleyan UniversityOhio Wesleyan University
Ohio Wesleyan University is a private liberal arts college in Delaware, Ohio, United States. It was founded in 1842 by Methodist leaders and Central Ohio residents as a nonsectarian institution, and is a member of the Ohio Five — a consortium of Ohio liberal arts colleges...
, in Delaware, Ohio
Delaware, Ohio
The City of Delaware is a city in and the county seat of Delaware County in the United States state of Ohio. Delaware was founded in 1808 and was incorporated in 1816. It is located near the center of Ohio, is about north of Columbus, and is part of the Columbus, Ohio Metropolitan Area...
. While a student at Ohio Wesleyan, he had made a "talking telegraph" and invented a receiver containing two features of the modern telephone: a permanent magnet and a metallic diaphragm that he made of a tintype
Tintype
Tintype, also melainotype and ferrotype, is a photograph made by creating a direct positive on a sheet of iron metal that is blackened by painting, lacquering or enamelling and is used as a support for a collodion photographic emulsion....
. He invented the first telephone receiver with a permanent magnet in 1865, 11 years before Alexander Graham Bell
Alexander Graham Bell
Alexander Graham Bell was an eminent scientist, inventor, engineer and innovator who is credited with inventing the first practical telephone....
patented his model. Later, Dolbear couldn't prove his claim, so Bell kept the patent. Dolbear lost his case before the U. S. Supreme Court, (Dolbear et al. v. American Bell Telephone Company). The June 18, 1881 edition of Scientific American reported:
- "had [Dolbear] been observant of patent office formalities, it is possible that the speaking telephone, now so widely credited to Mr. Bell would be garnered among his own laurels."
In 1876, Dolbear patented a magneto electric telephone. He patents a static telephone in 1879.
In 1882 Professor A. E. Dolbear was able to communicate over a distance of a quarter of a mile without wires in the Earth. It is interesting to note that the Tufts Professor was ahead of Hertz and Marconi. He received a U.S. patent for a wireless telegraph in March of that year. His device relied on conduction in the ground, a type of radio transmission. His set-up used phones grounded by metal rods poked into the earth. His transmission range was at least as much as a half a mile and he received a patent for this device, , in 1886. But more importantly the Dolbear patent prevented the Marconi Company from operating in the United States. In the end Marconi had to purchase Dolbear's patent, primarily because it was:
- Similar to the 1896 model of Guglielmo MarconiGuglielmo MarconiGuglielmo Marconi was an Italian inventor, known as the father of long distance radio transmission and for his development of Marconi's law and a radio telegraph system. Marconi is often credited as the inventor of radio, and indeed he shared the 1909 Nobel Prize in Physics with Karl Ferdinand...
. - Tractable in specific applications (such as transmission in the earth).
In 1868 Dolbear (while a professor at Bethany College) invented the electrostatic telephone. He also invented the opeidoscope (an instrument for visualizing vibration of sound waves, using a mirror mounted on a membrane) and a system of incandescent lighting. He authored several books, articles, and pamphlets, and was recognized for his contributions to science at both the Paris Exposition in 1881 and the Crystal Palace Exposition in 1882.
In 1897, Dolbear published an article "The Cricket as a Thermometer" that noted the correlation between the ambient temperature and the rate at which cricket
Cricket (insect)
Crickets, family Gryllidae , are insects somewhat related to grasshoppers, and more closely related to katydids or bush crickets . They have somewhat flattened bodies and long antennae. There are about 900 species of crickets...
s chirp. The formula expressed in that article became known as Dolbear's Law
Dolbear's Law
Dolbear's law states the relationship between the air temperature and the rate at which snowy tree crickets chirp...
.
Publications
Books- "The Art of Projecting", Boston, 1876
- "The Speaking Telephone" 1877
- "Sound and its Phenomena" 1885.
- "First Principles of Natural Philosophy", Boston, 1897.
- "Modes of Motion", Boston, 1897.
- "Matter, Ether, Motion,"
Journal articles
- "The Cricket as a Thermometer". The American Naturalist, Vol. 31, No. 371 (Nov., 1897), pp. 970-971. Published by The University of Chicago Press for The American Society of Naturalists
Patents
- "Apparatus for transmitting sound by electricity" Apr 5, 1881.
External articles
CitationsGeneral
