Bell Telephone Laboratories - Jacques Bernoulli
February 1960 Radio-Electronics

February 1960 Radio-Electronics [Table of Contents] Wax nostalgic about and learn from the history of early electronics. See articles from Radio-Electronics, published 1930-1988. All copyrights hereby acknowledged.

Being one of the world's premier communications technology companies, Bell Telephone Laboratories (aka Bell Labs) engineers and scientists relied heavily on mathematics for its accomplishment. It comes as no surprise, then, that one of their full-page promotions in a 1960 issue of Radio-Electronics magazine celebrated the accomplishments of mathematician Jacques Bernoulli. Bernoulli made significant contributions to a variety of mathematical fields, including calculus, number theory, probability theory, and physics. He is best known for his work on the calculus of variations, a branch of mathematics that deals with finding the optimal solution to a problem. In particular, he is famous for the "brachistochrone problem," which involves finding the path taken by a particle that travels between two points in the shortest time possible under the influence of gravity.

Bell Telephone Laboratories Ad -Jacques Bernoulli

Jacques Bernoulli - The Wizard of Odds

He solved a telephone traffic problem two centuries ago.

Jacques Bernoulli, the great Swiss mathematician, pondered a question early in the 18th century. Can you mathematically predict what will happen when events of chance take place, as in throwing dice?

His answer was the classical Bernoulli binomial distribution -a basic formula in the mathematics of probability (published in 1713). The laws of probability say, for instance, that if you roll 150 icosahedrons (the 20-faced solid shown above), 15 or more of them will come to rest with side "A" on top only about once in a hundred times.

Identical laws of probability govern the calls coming into your local Bell Telephone exchange. Suppose you are one of a group of 150 telephone subscribers, each of whom makes a three-minute call during the busiest hour of the day. Since three minutes is one-twentieth of an hour, the probability that you or any other subscriber will be busy is 1 in 20, the same as the probability that side "A" of an icosahedron will be on top. The odds against 15 or more of you talking at once are again about 100 to 1. Thus it would be extravagant to supply your group with 150 trunk circuits when 15 are sufficient for good service.

Telephone engineers discovered at the turn of the century that telephone users obey Bernoulli's formula. At Bell Telephone Laboratories, mathematicians have developed the mathematics of probability into a tool of tremendous economic value. All over the Bell System, the mathematical approach helps provide the world's finest telephone service using the least possible equipment. The achievements of these mathematicians again illustrate how Bell Laboratories works to improve your telephone service.

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