Turning Point Inventions: Telephone

Turning Point Inventions: Telephone

Hardcover

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Product Details

ISBN-13: 9780689828157
Publisher: Atheneum Books for Young Readers
Publication date: 09/01/1999
Series: Turning Point Inventions Series
Pages: 80
Product dimensions: 9.26(w) x 9.26(h) x 0.50(d)
Age Range: 10 - 14 Years

Read an Excerpt

From Chapter 4: A New World<

This confusion was partly because you couldn't see the person who was talking and partly because no one had yet talked back. All the earliest calls were one-way because the first receivers could only receive, not transmit. It wasn't until October 6, 1876, that Bell and Watson had their first conversation on the telephone in the rooms at Exeter Place, using two of the membrane transmitters, which they had discovered could also act as receivers. On October 9, they talked "long distance" over a two-mile telegraph line from Boston to Cambridge. Following the success of these two experiments, Bell announced that he had arrived at the "completion of Telephony," although he did note that he realized "much doubtless yet remains to be done in perfecting the details of apparatus."

He and Watson spent the rest of the year doing just that. By using a metal sheet, or diaphragm, instead of the original membrane, and a permanent magnet -- already magnetized, without the need for an electric current -- instead of an electromagnet in the transmitter/receiver, they got better results.

Using a permanent magnet meant that the telephone could operate without a battery. It also meant that Bell and Watson gave up the "liquid transmitter" -- which, with its dish of water, wasn't really practical for commercial use -- and returned to a telephone that operated by induction. in January 1877, Bell applied for and was granted a patent on the improvements. The two patents he now held -- good for seventeen years each -- were the basis for what became the largest and most successful business in American history.

Copyright © 1999 by CommonPlace Publishing LLC

Table of Contents

1Before the Telephone6
2The Inventor's Life16
3Inventing the Telephone26
4A New World42
5The Future of Long-Distance Communication72
Further Reading78
Index79
Acknowledgments80

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