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مراقب عام
عدد الرسائل : 65
تاريخ التسجيل : 13/06/2008
 |  موضوع: Alexander Graham Bel -- First invention  الثلاثاء يوليو 01, 2008 2:06 am | |
| First inventionAs a child, young Aleck Bell displayed a
natural curiosity about his world, resulting in gathering botanical specimens
as well as experimenting
even at an early age. His best friend was Ben Herdman, a neighbour whose family
operated a flour mill, the scene of many forays. When their typical child's
play had caused a racket one day, John Herdman admonished the two boys,
"Why don't you do something useful?" Young Aleck asked what needed to
be done at the mill. He was told wheat
had to be dehusked through a laborious process and at the age of 12, Bell built
a homemade device that combined rotating paddles with sets of nail brushes,
creating a simple dehusking machine that was put into operation and used steadily for a
number of years. [12]
In return, John Herdman gave both boys the run of a small workshop to
"invent."[12]EducationAs a young child, Bell, like his brothers, received his early
schooling at home from his father. At an early age, however, he was enrolled at
the Royal High School, Edinburgh, Scotland,
which he left at age 15, completing the first four forms only.[18]
His school record was undistinguished, marked by absenteeism and lacklustre
grades. His main interest remained in the sciences, especially biology, while
he treated other school subjects with indifference, to the dismay of his
demanding father.[19]
Upon leaving school, Bell travelled to London to live with his
grandfather, Alexander Bell. During the year he spent with his grandfather, a
love of learning was born, with long hours spent in serious discussion and
study. The elder Bell
took great efforts to have his young pupil learn to speak clearly and with
conviction, the attributes that his pupil would need to become a teacher
himself.[20]
At age 16, Bell secured a position as a
"pupil-teacher" of elocution and music, in Weston
House Academy,
at Elgin, Moray, Scotland. Although he was enrolled as a student
in Latin and Greek, he instructed classes himself in return for board and £10
per session.[21]
The following year, he attended the University of Edinburgh; joining his older
brother Melville who had enrolled there the previous year.First experiments with soundBell's father encouraged Aleck's interest in
speech and, in 1863, took his sons to see a unique automaton,
developed by Sir Charles Wheatstone based on the earlier work of
Baron Wolfgang von Kempelen.[22]
The rudimentary "mechanical man" simulated a human voice. Aleck was
fascinated by the machine and after he obtained a copy of von Kempelen's book,
published in German, and had laboriously translated it, he and his older
brother Melville built their own automaton head. Their father, highly
interested in their project, offered to pay for any supplies and spurred the
boys on with the enticement of a "big prize" if they were successful.[22]
While his brother constructed the throat
and larynx,
Aleck tackled the more difficult task of recreating a realistic skull. His efforts
resulted in a remarkably lifelike head that could "speak," albeit only a
few words.[22]
The boys would carefully adjust the "lips" and when a bellows
forced air through the windpipe, a very recognizable "Mama"
ensued, to the delight of neighbors who came to see the Bell invention.[23]Intrigued by the results of the automaton, Bell continued to
experiment with a live subject, the family's Skye terrier, "Trouve".[24]
After he taught it to growl continuously, Aleck would reach into its mouth and
manipulate the dog's lips and vocal cords to produce a crude-sounding "Ow ah oo ga ma
ma." With little convincing, visitors believed his dog could articulate
"How are you grandma?" More indicative of his playful nature, his
experiments convinced onlookers that they saw a "talking dog."[25]
However, these initial forays into experimentation with sound led Bell to undertake his
first serious work on the transmission of sound, using tuning forks
to explore resonance.
At the age of 19, he wrote a report on his work and sent it to Alexander Ellis,
a colleague of his father.[25]
Ellis immediately wrote back indicating that the experiments were similar to
existing work in Germany.
Dismayed to find that groundbreaking work had already been undertaken by Hermann von Helmholtz who had conveyed vowel
sounds by means of a similar tuning fork "contraption",
he pored over the German scientist's book, Sensations of Tone. From his
translation of the original German edition, Aleck then made a deduction that
would be the underpinning of all his future work on transmitting sound,
"Without knowing much about the subject, it seemed to me that if vowel sounds could be
produced by electrical means so could consonants,
so could articulate speech."[26]Work with the deafSubsequently, his father was invited by Sarah
Fuller, principal of the Boston School for Deaf Mutes (which continues today as the Horace Mann School
for the Deaf and Hard of Hearing),[40]
in Boston, Massachusetts,
United States,
to introduce the Visible Speech System by providing training for Fuller's
instructors, but he declined the post, in favor of his son. Travelling to Boston in April 1871, Bell provided a successful inservicing of the
school's instructors.[41]
He was subsequently asked to repeat the program at the American Asylum for Deaf-mutes in Hartford
and the Clarke School for the Deaf in Northampton.Returning home to Brantford
after six months abroad, Bell
continued his experiments with his "harmonic telegraph."[42]The
basic concept behind his device was that messages could be sent through a
single wire if each message was transmitted at a different pitch, but work on
both the transmitter and receiver as needed.[43]
Unsure of his future, he first contemplated returning to London
to complete his studies, but decided to return to Boston as a teacher.[44]
His father helped him set up his private practise by contacting Gardiner Greene Hubbard, the president of the Clarke School
for the Deaf for a recommendation. Teaching his father's system, in October
1872, Alexander Bell opened a school in Boston
named the "Vocal Physiology and Mechanics of Speech" which attracted
a large number of deaf pupils.[45]
His first class numbered 30 students.[46]
Working as a private tutor, one of his most famous pupils was Helen Keller,
who came to him as a young child, unable to see, hear or speak. She later was
to say that Bell
dedicated his life to the penetration of that "inhuman silence which
separates and estranges."[47]. | |
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