For those who would like to know more about Marcet's life and work, Evelyn L. Forget offers a useful overview in "Jane Marcet as Knowledge Broker" (History of Economics Review, 2016, vol. 65, pp. 15-26). Forget writes:
Jane Marcet was a popularizer of political economy whose textbook entitled Conversations on Political Economy was first published in 1816, went through at least 14 legal editions and was translated into French, Dutch, German, Spanish and Japanese. It was received with great acclaim not only by the public but also by economists such as Jean-Baptiste Say, David Ricardo and Thomas Robert Malthus. ... Marcet was engaged in the work of the knowledge broker--creating and maintaining networks between and among economists, scientists and the larger public. Knowledge sharing was based upon the personal and social connections she facilitated by bringing together bankers, scientists, and professional economists such as Malthus, Ricardo, James Mill, and others at her home.
Forget quotes a letter from Jean-Baptiste Say to Marcet:
"You have worked much more efficiently than I to popularize and to spread extremely useful ideas; and you will succeed Madame, since you have built on the strength of science... It is not possible to stay closer to the truth with more charm; to clothe such indisputable principles with a more elegant style. I am an old soldier who asks only to die in your light.
Indeed, Say requested permission from Marcet to translate "sizeable passages from your excellent book," which often consisted of sections where Marcet was explaining Say's own work. Forget also quotes a comment from a letter from Thomas Malthus to Marcet:
"I own I had felt some anxiety about the success of your undertaking, both on account of its difficulty, and its utility; and I am very happy to be able to say that I think you have overcome the first and consequently insured completely the second.... I am much obliged to you for your explanations on rents, and think you have managed some other difficult subjects remarkably well, particularly the subject of exchanges and bill merchants ..."
Marcet's books were typically in the form of conversations between Mrs. B and Caroline, and sometimes also with Caroline's sister Emily. The dialogue rarely sparkles, but as a work of pedagogy, the format allows Marcet to express doubts, uncertainties and mistakes--and then to address them.
To offer a taste of the style, here is an excerpt from "Conversation I" between Mrs. B. and Caroline at the start of her book on political economy, which is subtitled "Errors arising from total ignorance of political economy.—advantages resulting from the knowledge of its principles. — difficulties to be surmounted in this study." The passage does contains a couple of my favorite comments: the opening speech by Caroline on how political economy is "the most uninteresting of all subjects" and the later admonition from Mrs. B. that "when you plead in favour of ignorance, there is a strong presumption that you are in the wrong." I quote here from the edition of the book available via the Online Library of Liberty.
CAROLINE: I confess that I have a sort of antipathy to political economy.
MRS. B.: Are you sure that you understand what is meant by political economy?
CAROLINE: I believe so, as it is very often the subject of conversation at home; but it appears to me the most uninteresting of all subjects. It is about custom-houses, and trade, and taxes, and bounties, and smuggling, and paper-money, and the bullion-committee, &c. which I cannot hear named without yawning. Then there is a perpetual reference to the works of Adam Smith, whose name is never uttered without such veneration, that I was induced one day to look into his work on Political Economy to gain some information on the subject of corn, but what with forestalling, regrating, duties, draw-backs, and limiting prices, I was so overwhelmed by a jargon of unintelligible terms, that after running over a few pages I threw the book away in despair, and resolved to eat my bread in humble ignorance. So if our argument respecting town and country relates to political economy, I believe that I must be contented to yield the point in dispute without understanding it.
MRS. B.: Well, then, if you can remain satisfied with your ignorance of political economy you should at least make up your mind to forbear from talking on the subject, since you cannot do it to any purpose.
CAROLINE: I assure you that requires very little effort; I only wish that I was as certain of never hearing the subject mentioned as I am of never talking upon it myself.
MRS. B.: Do you recollect how heartily you laughed at poor Mr. Jourdain in the Bourgeois Gentilhomme, when he discovered that he had been speaking in prose all his life without knowing it? — Well, my dear, you frequently talk of political economy without knowing it. But a few days since I heard you deciding on the very question of the scarcity of corn; and it must be confessed that your verdict was in perfect unison with your present profession of ignorance.
CAROLINE: Indeed I only repeated what I had heard from very sensible people, that the farmers had a great deal of corn; that if they were compelled to bring it to market there would be no scarcity, and that they kept it back with a view to their own interest, in order to raise the price. Surely it does not require a knowledge of political economy to speak on so common, so interesting a subject as this first necessary of life.
MRS. B.: The very circumstance of its general interest renders it one of the most important branches of political economy. Unfortunately for your resolution, this science spreads into so many ramifications that you will seldom hear a conversation amongst liberal-minded people without some reference to it. It was but yesterday that you accused the Birmingham manufacturers of cruelty and injustice towards their workmen, and asserted that the rate of wages should be proportioned by law to that of provisions; in order that the poor might not be sufferers by a rise in the price of bread. I dare say you thought that you had made a very rational speech when you so decided?
MRS. B: I do not know; but I have no doubt that I shall convince you of your incapacity to enter on most subjects of general conversation, whilst you remain in total ignorance of it; and that however guarded you may be, that ignorance will be betrayed, and may frequently expose you to ridicule. During the riots of Nottingham I recollect hearing you condemn the invention of machines, which, by abridging labour, throw a number of workmen out of employment. Your opinion was founded upon mistaken principles of benevolence. In short, my dear, so many things are more or less connected with the science of political economy, that if you persevere in your resolution, you might almost as well condemn yourself to perpetual silence.
CAROLINE: I should at least be privileged to talk about dress, amusements, and such lady-like topics.
MRS. B.: I have heard no trifling degree of ignorance of political economy betrayed in a conversation on dress. “What a pity,” said one lady, “that French lace should be so dear; for my part I make no scruple of smuggling it; there is really a great satisfaction in cheating the custom-house.” Another wondered she could so easily reconcile smuggling to her conscience; that she thought French laces and silks, and all French goods, should be totally prohibited; that she was determined never to wear any thing from foreign countries, let it be ever so beautiful; and that it was shameful to encourage foreign manufactures whilst our own poor were starving.
MRS. B.: I have heard no trifling degree of ignorance of political economy betrayed in a conversation on dress. “What a pity,” said one lady, “that French lace should be so dear; for my part I make no scruple of smuggling it; there is really a great satisfaction in cheating the custom-house.” Another wondered she could so easily reconcile smuggling to her conscience; that she thought French laces and silks, and all French goods, should be totally prohibited; that she was determined never to wear any thing from foreign countries, let it be ever so beautiful; and that it was shameful to encourage foreign manufactures whilst our own poor were starving.
CAROLINE: What fault can you find with the latter opinion? It appears to me to be replete with humanity and patriotism.
MRS. B.: The benevolence of the lady I do not question; but without knowledge to guide and sense to regulate the feelings, the best intentions will be frustrated. The science of political economy is intimately connected with the daily occurrences of life, and in this respect differs materially from that of chemistry, astronomy, or any of the natural sciences; the mistakes we may fall into in the latter sciences can have little sensible effect upon our conduct, whilst our ignorance of the former may lead us into serious practical errors. ...
CAROLINE: Well, after all, Mrs. B., ignorance of political economy is a very excusable deficiency in women. It is the business of Government to reform the prejudices and errors which prevail respecting it; and as we are never likely to become legislators, is it not just as well that we should remain in happy ignorance of evils which we have no power to remedy?
MRS. B.: When you plead in favour of ignorance, there is a strong presumption that you are in the wrong.
MRS. B.: The benevolence of the lady I do not question; but without knowledge to guide and sense to regulate the feelings, the best intentions will be frustrated. The science of political economy is intimately connected with the daily occurrences of life, and in this respect differs materially from that of chemistry, astronomy, or any of the natural sciences; the mistakes we may fall into in the latter sciences can have little sensible effect upon our conduct, whilst our ignorance of the former may lead us into serious practical errors. ...
CAROLINE: Well, after all, Mrs. B., ignorance of political economy is a very excusable deficiency in women. It is the business of Government to reform the prejudices and errors which prevail respecting it; and as we are never likely to become legislators, is it not just as well that we should remain in happy ignorance of evils which we have no power to remedy?
MRS. B.: When you plead in favour of ignorance, there is a strong presumption that you are in the wrong.