The First Scientific American

by Joyce Chaplin

  This polite back-and-forth evinced enough trust for Franklin and Colden to begin a serious correspondence in 1744, when both were putting their thoughts on natural philosophy into print. Franklin did so with his pamphlet on fireplaces, which Colden read and then sent to Johann Friedrich Gronovius, a Dutch naturalist who had the pamphlet translated and printed in Leiden, the Netherlands. This edition was Franklin’s first overseas publication.58

  Colden meanwhile circulated drafts of some essays on “fluxions,” a term (no longer used) that described the rate of change in a mathematical function. He claimed to have discovered the cause of gravitation, not through experiment or observation but by rational and mathematical analysis of some of the major texts in mechanics. Colden realized his work was speculative. “I have open’d to my self a large Prospect either into Nature or into Fairyland,” he confessed to Franklin, and he wished to “lay it step by step before my Friends for their remarks.” He sent Franklin part of his manuscript to share with Logan. Franklin was eager to tell Colden that he had passed the draft to Logan but was less keen to express Logan’s disbelief (“he thought you had not fully hit the Matter”), and he was suspiciously slow to offer Colden his own thoughts.59

  Colden was the anti-Franklin—he made haste hastily. Determined to make his mark, he published An Explication of the First Causes of Action in Matter; and the Cause of Gravitation in New York in 1745. His work explained the cause of gravitation, a problem on which even “Sir Isaac Newton [had] stopt short.” Newton had proposed that aether filled the universe, exerting a force that caused gravitation; Colden said that it was the aether itself, its imponderable particles resisting matter, that created a special force on celestial bodies—it was gravity. On the strength of this claim, the book was translated and published all over Europe. Experts tore into it. Swiss mathematician Leonhard Euler wrote a critique, read at the Royal Society, that described Colden’s explication as “so ill managed, that it is absolutely contrary to the first principles of Hydrostaticks.” It was “an absurdity,” he pronounced, for Colden to claim “that the Ether between Two of the Coelestial Bodies, has not the same Spring [resisting force] as that of the Rest” of matter. The Royal Society declined to read Colden’s rebuttal.60

  Yet Colden’s boldness and reach obviously appealed to Franklin, who had offered to publish the book—no other colonist’s work in natural philosophy had been so widely disseminated abroad. The mathematically challenged Franklin was unable to assess Colden’s work, but he knew quite well that work in physics mattered more than any other attempt in the sciences. And he may have learned another lesson from Colden: do not publish your work in America but have it vetted and printed in Europe. He realized that the circulation of ideas in letters, which were essentially rough drafts, was very important.61

  Colden and Franklin were on common—and safer—ground when they discussed the human body. In 1745, Colden sent Franklin the draft of another work, probably a version of his 1730s treatise entitled “The Animal Oeconomy.” No strategic silence this time—Franklin sent back two letters that together formed a detailed response on the functioning of the body, starting with the question of invisible perspiration. “After I had read Sanctorius,” he explained, “I imagin’d a constant Stream of the perspirable Matter issuing at every pore in the Skin.” Yet the leaky body also managed to absorb fluids. How did the skin accomplish this two-way flow? Franklin and Colden agreed that the skin perspired and respired at the same time, through different “Ducts.” This process had to be possible, Franklin insisted, even if the outward movement of fluids was better known and more powerful than any inward motion. If laid against the skin, for instance, a medicine’s entry into the body “must go against Wind and Tide, (as one may say).”62

  Their letters on this question revealed a crucial difference between Franklin and Colden: experiments. Whereas Colden reasoned his way through problems, Franklin liked demonstration.

  At Archibald Spencer’s Boston lectures, Franklin had just seen a glass mechanism that showed the circulation of the blood, and he may have bought the “Apparatus” around that time. With this as a possible model, Franklin built his own “little Machine” to show that fluids could, within the same system, move in opposite directions. He joined two pieces of hollow cane so they met at an apex, like a capital A. Water sent through the left-hand, ascending cane would rise and then descend through the right-hand cane. He then inserted two small glass tubes to stand above each cane, as if the A were now wearing horns. Water introduced through the cane on the left now spurted through the left-hand glass tube but not the right-hand one, even if some of the water traveled all the way through both sections of cane. As if they were two pores, one glass tube carried fluid outward, but the other resisted the flow and could (presumably) receive a different fluid if pressure in the system was low enough.63

  Having corrected Sanctorius, Franklin also used his letters to Colden to comment on Harvey. He pointed out that Harvey’s description of the heart’s valves, which variously pumped blood inward and outward, indicated how a two-way circulation might exist in other parts of the body. Franklin then appended speculations on the cause of warmth in the blood. Friction could create heat—as anyone who rubs his or her cold hands together knows. Did it warm the blood? If so, where did the friction occur? Franklin concluded that the heart, moving as it pumped blood, had to “produce a Heat” that was then transferred to the blood, which circulated it through the body. This scenario was likelier than blood creating heat itself; fluids, though particulate, were too smooth to generate the necessary friction, which the heart’s tissue could do.64

  Franklin’s “little Machine” (now lost) was inventive, but most of his arguments in his letters to Colden did little more than embellish Harvey and Sanctorius. He was more original when he posited analogies to the human body, moving outward to the macrocosm and reasoning about heat and fluid circulation as universal properties. Sun, heart, Pennsylvania fireplace—each one heated a fluid (air or blood) within a distinct atmosphere, whether around the earth, in the body, or through a room. In similar fashion, Franklin proposed that “Food in the Stomach” was equivalent to “Fuel in a Chimney”; they kept a body or a room warm. If the body was analogous to a room, an even larger atmosphere could resemble a set of rooms. Franklin would complain of London’s dirty air in 1758, declaring, “The whole Town is one great smoaky House, and every Street a Chimney,” thus making many sooty microcosms within the macrocosm of the metropolis.65

  WAR called Franklin and Colden from their philosophical reveries in the late 1740s. The War of Jenkins’s Ear (1739–1744) was merging into the War of the Austrian Succession (1744–1748), which the colonists called King George’s War. Both conflicts involved land battles, but colonists probably worried at least as much about their naval maneuvers. Jenkins lost his ear to a Spanish coast guard vessel in 1739, provoking one war; New Englanders sent a private flotilla to seize French Louisbourg in the Atlantic Maritimes in 1745, escalating another. Men such as Colden and Franklin were still eager to discuss the natural world, but they now took up topics relevant to public affairs, including navigation, defense, and the value of the colonies within the empire.

  Getting ships across the Atlantic was a paramount wartime concern, which may have been why, in a 1746 letter to Colden, Franklin considered “the much shorter Voyages made by Ships bound hence to England, than by those from England hither,” which he had noticed on his own two Atlantic crossings. He thought the difference must be “in some Degree owing to the Diurnal Motion of the Earth” but also considered that ships’ structure would affect the resistance of the water.66

  Colden likewise attributed the phenomenon to multiple causes. The “more frequent westerly winds” across the Atlantic must play a part, he said; so too did the tides. Probably referring to the work of Edmond Halley, Colden observed that high tides could be mapped in regular patterns over the globe and their effects calculated, showing that a ship crossing westward in thirty days w
ould have the tidal force “lessen’d 1/30 of the time as she approaches” America. Assuming that all ships could be constructed and loaded in the same way, an “equation” to calculate the rates of east and west passages at different times of year should be possible.67

  But after this initial exchange on the topic, Franklin dropped it—for two decades. He may have done so because although the question had “entred” his “Mind,” he was not sure if it ever had “any other’s.” This doubt had accompanied his first analysis of the North Atlantic in 1726, when he feared his perceptions might be his “opinion” alone. If he and Colden were the only two people who found the problem interesting, they might have no audience for their solution. And for the time being, there was no way to address the problem through experimentation and direct observation, both of which mattered to Franklin if not to Colden.68

  Above all, the war-torn Atlantic world reminded Franklin that he was still on the edge of nowhere, as far as Europeans were concerned. In 1745, he assured his London book-buyer, William Strahan, that the colonial market for books remained steady—literate colonists fell over themselves to read whatever had been printed abroad. “Your authors know but little of the Fame they have on this Side the Ocean,” Franklin explained; “we are a kind of Posterity in respect to them. We read their Works with perfect Impartiality, being at too great a Distance to be byassed by the Fashions, Parties and Prejudices that prevail among you.” Only in far-off Philadelphia, Franklin implied, could one both read and appreciate European texts.69

  But the distance—and difference—between the Eastern and Western Hemispheres was narrowing. As their populations grew, colonies were less dependent on Europe for immigrant labor and basic supplies. Instead, colonists imported more finished goods, including the piles of printed material that indicated their growing intellectual sophistication. Not that metropolitan authorities took note of this. The war made it apparent to Franklin that imperial officials would not even guarantee defense for the colonies, including Pennsylvania. In 1747, he published two essays that addressed, in remarkably different ways, the relationship between Britain and the American colonies.70

  Plain Truth was Franklin’s first overtly political statement. In it, he indicted the colony’s leaders for abdicating their duty to defend Pennsylvania and recommended a voluntary military association to fill the void. Spanish privateers along the North American coast had raised fears of an attack on the mid-Atlantic colonies. Pennsylvania’s elite (especially the Quakers) were nevertheless reluctant to invest in military defense. “Common Sense and Goodness” required greater vigilance, Franklin urged. Even if the war spared Philadelphia itself, privateering would hurt its trade, which was “in Danger of being ruin’d in another Year.” To rely on the Royal Navy for defense was a foolish and short-term solution. If Pennsylvania paid for its own naval defense, the money given to its own shipwrights and sailors “remains in the Country, and circulates among us.” Military investment was, therefore, an investment in both the economy and public safety: “Publick Money, raised from All, belongs to All.”71

  Franklin was not subtle. He signed his pamphlet as “A TRADESMAN of Philadelphia” and thereby made clear that he stood apart—socially and morally—from Pennsylvania’s genteel elite. He also illustrated the piece with a cartoon that showed a man praying for divine assistance to get his cart out of the mud. A Latin tag to the cartoon (“Non Votis, &c.”) roughly translates as “God helps those who help themselves.”72

  The pamphlet “had a sudden and surprizing Effect,” much more than Franklin had expected and more than anything he had written before. If it was an experiment in promoting himself, it worked. When Franklin presented his scheme to “a Meeting of the Citizens,” he “harangu’d them a little,” read his essay, and then distributed copies of a plan for association. He garnered over 500 signatures on the spot, and that number doubled within a week. He also persuaded some powerful supporters, including Logan. By the fall of 1747, the colonial militia was formed. Franklin declined to serve as colonel of the Philadelphia regiment, but he had clearly become a figurehead in colonial politics. He won his first elected position the next year, 1748, when he became a member of the Philadelphia Common Council. The military force he had helped create served two functions. It defended the colonies from external attack, and it deflected British critics who claimed the colonists were too weak to help themselves.73

  Even as Franklin defended the colonies within the masculine world of politics and war, he adopted a female pseudonym to admit the colonies’ backwardness. He wrote the “Speech of Miss Polly Baker” in 1746 and published it anonymously in a London newspaper the next year. In this piece, Miss Baker makes her speech from a Connecticut courtroom. Charged with fornication (the evidence was an illegitimate baby, her fifth), Baker protests that she had merely followed the “Command of Nature, and of Nature’s God, Encrease and Multiply,” her “steady Performance of which” was a benefit “in a new Country that really wants People.” This inventive defense, among others, inspires the court to drop all charges against Baker and one of her judges “to marry her the next day.”74

  Prodigal daughter of Silence Dogood and errant cousin of Bridget Saunders, Baker shares her paper kinswomen’s lively tone but transcends their bloodlessness. Baker exists because of her scandalous body, and she is suitably vivid in detailing its ability to work and to produce children. The smitten judge stands for us; we are meant to appraise Baker and then fall for her.

  Through Baker, Franklin acknowledged his provinciality—he lived “in a new Country that really wants People.” The colonies still depended on imports of all kinds, from finished goods to people, especially the young people who could work and reproduce. Baker argued that she did both, supporting her progeny without charity. (Poor Richard had already compared the two ways that the colonies acquired what they “wanted” when he declared in 1735 that “A Ship under sail and a big-bellied Woman, / Are the handsomest two things that can be seen common.”) But the tide was turning. Franklin was, by the mid-1740s, beginning to see that natural reproduction would make the colonists powerful. With enough of the diligence that Baker exhibited, colonials would outnumber Britons. “God helps those who help themselves” indeed.75

  In Plain Truth and the “Speech of Miss Polly Baker,” Franklin was, for the first time, summoning nature to make a political argument. By the middle of the eighteenth century, languages of science and law had intriguing areas of overlap. Natural philosophers drew on the idea of law to argue for nature’s uniformity and regularity; legal theorists called on the sciences to argue for law’s inevitability. (The claims of political arithmetic, based on probability, were similar, if less certain.) Now, the concept of a fact—a hard, durable truth—became a political tool. People could not resist arguing that facts simply existed and spoke for themselves. The fruitful convergence of law and science was rhetorically seductive. Newton may have warned that even the idea of gravity (stones falling) needed to be tested; meanwhile, many a second-rate lawyer and would-be politician insisted that facts, truth, nature, and law all confirmed whatever point he was trying to make.76

  Franklin had stuck to probability when he examined political arithmetic, but actual politics made him bolder. The two words in the title of his call to arms, plain and truth, made a rhetorical bid for the self-evident nature of his argument. Meanwhile, Baker, like her anonymous creator, leans hard on the argument from design. Note that she does not cite scripture; she credits nature, not the book of Genesis, even though her words “Encrease and Multiply” come from the King James Bible. Indeed, nature matters more than its Creator, if the order in which Baker/Franklin listed them is any indication. It was a rather scandalous package, had anyone bothered to catalog its contents.

  FRANKLIN had produced Plain Truth and “Polly Baker” almost as asides—natural philosophy was, finally, demanding every moment of his time as the war wound down in 1747. His experiments consumed him. “I have, during some months past, had little leisur
e for any thing else,” he confessed. Franklin had fallen under electricity’s spell.77

  He was not alone. His contemporaries were fascinated by electricity, even though no one knew quite what it was. People had long known about static electricity, associating it with substances (amber, glass, kittens) that, with a little friction, generated a weak charge. In the seventeenth century, philosophers had remarked on electricity’s resemblance to magnetism and had begun to explain it in similar terms, as an elastic fluid or imponderable. In this way, investigators made electricity into a substance they could visualize, as if it were an oddly fine, dry, and crackling form of water. But how could they explain it? Answering the question might define electricity and, even better, shed light on the universal construction of matter. Was electricity akin to Newton’s aether, the subtle fluid that pervaded the universe and helped explain physical things? Or might electrical matter show new things about all of matter, challenging natural philosophers to redefine their theories?78

  By the 1740s, electrical investigations had become a kind of craze. Demonstrators’ equipment and vocabulary had grown fairly complicated. To experiment with electricity, natural philosophers (and popular demonstrators such as Archibald Spencer) produced it by revolving a large and smooth piece of rounded glass against their hands or a padded surface. An experimenter could then put the electrostatic charge through something—sometimes a metal rod, sometimes a light person (a child, for instance) suspended in silk cords. By 1739, an Englishman had coined the terms conductor and insulator to indicate which substances did or did not carry a charge.79