Benjamin Franklin, an American Life

Walter Isaacson

Simon and Schuster, 2003. 590 pages

Available from for $20.40
($11.87 paperback), plus shipping.

I learned in school that the first American physicist was Joseph Henry (1798-1878), who discovered the phenomenon of self-inductance.1 In fact the SI unit of inductance is the Henry. However after reading (donít miss it!) this biography of Ben Franklin I realized how misled I had been: Franklin was the first American physicist.

We usually think of Ben Franklin (1706-1790) as a tinker who flew kites in thunderstorms and perhaps invented one or two useful gadgets like bifocal spectacles and lightning rods. And if course we know about Poor Richardís Almanac (which he began publishing in Philadelphia in 1732) and its many famous aphorisms such as "Early to bed and early to rise make a man healthy and wealthy and wise." Beyond that for some reason we are pretty ignorant of this 18th Century luminary, one of the great thinkers of the Enlightenment.

First, his credentials as a physicist. He discovered that electric charge came in two flavors which he named positive and negative. He discovered, experimentally the law of conservation of charge; the late distinguished historian of science I. Bernard Cohen stated, "Franklinís law of conservation of charge must be considered to be of the same fundamental importance to physical science as Newtonís law of conservation of momentum." He also discovered that electricity preferred to move through pointed objects rather than rounded, and thus was led to invent the lightning rod (after his kite experiment demonstrated that lightning was nothing more than an electrical discharge).

He also was the first person to measure the size of a molecule. Of course, the existence of molecules only became to be generally accepted in the 1800ís due to the work of John Dalton, but nonetheless Franklinís data were then available on their size. His experiment was to pour a teaspoonful of oil onto a still pond and measure the area to which the oil spread. By dividing the volume of the teaspoon by the area, he came up with 10-7 for the thickness of the film. This gives an upper limit for the size of an oil molecule, and is certainly within the correct order of magnitude. (This experiment was reported in the Philosophical Transactions of the Royal Society of which Franklin was the first American fellow.)

Dr. Franklin2 also studied the causes of colds (concluding that they were spread by contagion rather than cold air). While this is not physics, it did lead him to consider the effect of exercise on what we now all the immune system (since he had observed that people who exercised caught fewer colds). He related the amount of exercise to the rise in body temperature, thereby anticipating the first law of thermodynamics by about 100 years.

He also discovered lead poisoning, from his observation as a printer that handling of lead type often lead to paralysis and other trauma. This observation was extended to people who drank rum from stills with lead coils. He suggested ways for tradesmen to avoid lead poisoning, and suggested that the coils of stills be made of tin rather that lead.

Lead poisoning has an interesting connection with another of his inventions, the "glass harmonica." This musical instrument consists of a number of glass bowls of varying diameter mounted concentrically on a spindle, which can be rotated by means of a foot treadle. The musician evokes an ethereal type of music by wetting his fingers and touching the rims of the bowls as they rotate (rather like running your wet fingers around the rim of a crystal goblet). This instrument was very popular at one time; the author points out that glass harmonica compositions were written, inter alia,  by Mozart and Beethoven.

Because of the unearthly sound of its music, the glass harmonica was associated with insanity. In fact in his opera Lucia di Lammermoor Gaetano Donizetti scored the famous Mad Scene for glass harmonica obbligato. Today the glass harmonica is replaced by a flute or two, but in a memorable performance of Lucia at the Metropolitan Opera about 10 years ago the glass harmonica was used.3 This instrument eventually went out of fashion because so many of the musicians who performed on it went mad, like Lucia, and it was assumed that the eerie music had driven them insane. Today we know that they were suffering from lead poisoning, induced by their licking their fingers after they had been in contact with the lead-based glass of the instrument. (Mental disturbance is another symptom of lead poisoning it turns out.)

Other inventions of Dr. Franklinís included the copperplate press, a copy machine, daylight savings time, the storage battery, the Franklin stove, street lamps and who knows what else.

Up to this point I have concentrated on Franklinís scientific work because of the nature of this journal. But even if there been no scientific achievements Ben Franklin would have still had a remarkable careeróin politics. He crossed the Atlantic eight times,4 visiting England twice and France twice. During his two trips to England he tried to avert the coming Revolutionary War by attempting to wring concessions from the British government. When this failed, he returned to Philadelphia were he helped Thomas Jefferson write the Declaration of Independence and was among the signers. He then set out for France where he was successful in persuading the French to enter the war on the side of America and later, after Yorktown, negotiated the treaty of peace with Britain. He remained in France from 1776-1785 and even at the advanced age of 70 managed to learn passable French.

In Europe he was accepted by the intellectual community, hobnobbing with such luminaries as Adam Smith, David Hume, Voltaire, Boswell, Beaumarchais5 and others. Then upon his return to what by then could be called the United States he became one of the principal architects of the U.S. Constitution. Usually one thinks of James Madison in this role, but without Franklinís prestige as an elder statesman and his spirit of compromise the Constitution would never have come into being. In between all his other activities he found time to found the University of Pennsylvania and the first lending library in America, an idea which 150 years later attracted the attention of Andrew Carnegie and led to his establishing libraries all over the United States.

It is hard to believe that Franklin did all this with only two years of formal schooling but that is indeed the case.

There is a great deal more in this biography than I have been able to discuss, for example Franklinís strange domestic life. He never married, but lived in a common-law relationship with Deborah Read from 1730 until her death in 1774. Although this marriage was never regularized, Deborah is usually referred to as Franklinís wife, and their two children, Franky (who died at age 4) and Sally were considered legitimate. Franklin also had an illegitimate son, William, by an unknown mother. William, who went on to become governor of New Jersey (and who opposed the revolution) also had an illegitimate son, Temple, who in turn had illegitimate children.6 Franklinís relationships with his children and wife were strange. In brief, he basically ignored them and devoted much of his emotional energy to (apparently asexual) relationships with other women. He did however establish quasi relationships with his grandson Temple and another grandson Sallyís son Benny Bache.

Franklinís life as been summed up eloquently by Anne-Robert-Jacques Turgot, the French statesman:

Erepuit caelo fulmen sceptrumque tyrannis.7

Please read this book. Youíll be glad you did.

1. He also discovered mutual inductance independently of Michael Faraday.

 2.Franklin was awarded honorary doctorates by the University of St. Andrews in Scotland (1759) and Oxford University (1762). He also was invited to lecture at Cambridge University. After he received the degree from St. Andrews he always referred to himself as "Dr. Franklin."

 3. I taped the Mad Scene from the radio broadcast. Anyone interested in hearing what it sounds like should contact me:
 4. Remember that each trip, in a sailing boat, took a month.

 5. Isaacson discusses Beaumarchais briefly. However he fails to mention that this meeting took place between the 18th centuryís greatest intellects, something certainly worth pointing out (like the meeting of Sts. Augustine and Ambrose in the fifth century). To read my own notes on Beaumarchais go to

 6. Among the many useful inventions of Ben Franklin one does not find the condom.

 7. "He snatched lightning from the sky and the scepter from tyrants." Immanuel Kant seconded the motion when he called Franklin "the new Prometheus."