Engines of Our Ingenuity

No. 744:

by John H. Lienhard

Click here for audio of Episode 744.

Today, Mrs. B gives me a lesson in good teaching. The University of Houston's College of Engineering presents this series about the machines that make our civilization run, and the people whose ingenuity created them.

Jane Haldimand was born in 1769, the daughter of a wealthy London merchant. We know little of her early life. She married a Swiss doctor, Alexander Marcet, when she was thirty. He was a fairly distinguished professor of medicine -- on his way to becoming quite wealthy. But Jane Haldimand, now Jane Marcet, was not one for a gilded cage. Soon after her marriage, she began writing instructive books for young people.

The title of her first book was Conversations on Chemistry, intended more especially for the female sex. It came out in 1806. The style is arresting. It's a running conversation between a Mrs. B and two young ladies, Caroline and Emily.

Listen as they talk about heat radiation. Mrs. B says,

Before I conclude the subject ... I must observe ...
that different surfaces [radiate heat] in different degrees.

Emily asks, "These surfaces [are all] the same temperature?" Mrs. B answers, "Undoubtedly. I will show you [an] ingenious apparatus." She produces a cubical tin. One side is sanded, one rusted, one covered with soot, one polished.

She fills the tin with hot water. Then she uses a focusing mirror to reflect the heat from each side onto a thermometer. She gets four different readings. I'm going to recommend that experiment for our thermal lab at the university.

Within a gentle parlor propriety, Mrs. Marcet and her alter ego, Mrs. B, boldly take on any subject. They talk about Watt's new steam engine -- its valving and power takeoff mechanism.

Of course, the appeal of that kind of material wasn't limited to young women. My American edition belonged to someone named Charles Smith, who lived in Baltimore in 1835. He's made marginal notes about lime water and about the solubility of tree gums.

After this book, Marcet wrote on political economy, geology, and much more. Her book on political economy was very popular. It sold over 160,000 copies in America alone.

A crinoline wall separated women and men intellectually in 1800. Jane Marcet lived behind that wall. Yet her books marched out into the middle of the 19th century and helped transform it.

The year she wrote her book on chemistry, a 15-year-old boy worked in a London bookbindery. He was Michael Faraday. When Marcet's book passed through, he read it. It transformed him. Faraday went on to create our modern concepts of electricity.

The crowning irony is on page 105 in the 1833 edition of her chemistry book. On page 105 the editor has added a version of the experiment in which Faraday anticipated the electric motor. Already the book bears the fruit of her first edition. And Mrs. Marcet has given me -- a new role model for my teaching.

I'm John Lienhard, at the University of Houston, where we're interested in the way inventive minds work.

(Theme music)

My biographical sources were the Dictionary of National Biography articles on Jane and Alexander Marcet and her uncle, Frederick Haldimand. He was a hero of our French and Indian War.

Jones, T.P., New Conversations on Chemistry... Philadelphia: John Grigg, 1833. (This is an updating of Marcet's original book, which was published in 1806. I couldn't lay my hands on a copy of the original.)

Marcet, J. Conversations on Political Economy ... , 5th ed. London: Longman etc., 1824.

Marcet, J., The History of Africa ... London: H. Colburn and R. Bentley, 1830.

Williams, L.P., Faraday, Michael. Dictionary of Scientific Biography (C.C. Gilespie, ed.). Charles Scribner's Sons, 1970-1980.

In modern terms, Mrs. B's radiation experiment showed how the the radiant emittance of each side of the tin is different. As that property varies, so does the heat emitted from each side. The sooty side emits about 95 percent of a theoretical maximum. The polished side probably emits less than 5 percent. (See e.g., Lienhard, J.H., A Heat Transfer Textbook, Englewood Cliffs, NJ: Prentice-Hall, Inc., 1981 and 1987, Table 11.1, Chapter 11.)

Jane Marcet died in 1858 at the age of 89. By then, she'd strongly influenced her good friend, the famous English author Harriet Martineau. Martineau began by writing her own version of Marcet's Political Economy. She went on to become a powerful advocate of religious liberalism and the abolition of slavery.

For more on Marcet, see Episodes 741, 745, 828, 900, and 950.

The Engines of Our Ingenuity is Copyright © 1988-1997 by John H. Lienhard.

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