---
title: "Benjamin Franklin"
chunk: 12/18
source: "https://en.wikipedia.org/wiki/Benjamin_Franklin"
category: "reference"
tags: "science, encyclopedia"
date_saved: "2026-05-05T04:06:16.447701+00:00"
instance: "kb-cron"
---

An aging Franklin accumulated all his oceanographic findings in Maritime Observations, published by the Philosophical Society's transactions in 1786. It contained ideas for sea anchors, catamaran hulls, watertight compartments, shipboard lightning rods and a soup bowl designed to stay stable in stormy weather.
While traveling on a ship, Franklin had observed that the wake of a ship was diminished when the cooks scuttled their greasy water. He studied the effects on a large pond in Clapham Common, London. "I fetched out a cruet of oil and dropt a little of it on the water ... though not more than a teaspoon full, produced an instant calm over a space of several yards square." He later used the trick to "calm the waters" by carrying "a little oil in the hollow joint of [his] cane."

=== Meteorology ===

On October 21, 1743, according to the popular myth, a storm moving from the southwest denied Franklin the opportunity of witnessing a lunar eclipse. He was said to have noted that the prevailing winds were actually from the northeast, contrary to what he had expected. In correspondence with his brother, he learned that the same storm had not reached Boston until after the eclipse, despite the fact that Boston is to the northeast of Philadelphia. He deduced that storms do not always travel in the direction of the prevailing wind, a concept that greatly influenced meteorology. After the Icelandic volcanic eruption of Laki in 1783, and the subsequent harsh European winter of 1784, Franklin made observations on the causal nature of these two seemingly separate events. He wrote about them in a lecture series.

=== Population studies ===
Franklin had a major influence on the emerging science of demography or population studies. In the 1730s and 1740s, he began taking notes on population growth, finding that the American population had the fastest growth rate on Earth. Emphasizing that population growth depended on food supplies, he emphasized the abundance of food and available farmland in America. He calculated that America's population was doubling every 20 years and would surpass that of England in a century. In 1751, he drafted Observations concerning the Increase of Mankind, Peopling of Countries, etc. Four years later, it was anonymously printed in Boston and was quickly reproduced in Britain, where it influenced the economist Adam Smith and later the demographer Thomas Malthus, who credited Franklin for discovering a rule of population growth. Franklin's predictions on how British mercantilism was unsustainable alarmed British leaders who did not want to be surpassed by the colonies, so they became more willing to impose restrictions on the colonial economy.
Kammen (1990) and Drake (2011) say Franklin's Observations concerning the Increase of Mankind (1755) stands alongside Ezra Stiles's "Discourse on Christian Union" (1760) as the leading works of 18th-century Anglo-American demography; Drake credits Franklin's "wide readership and prophetic insight." Franklin was also a pioneer in the study of slave demography, as shown in his 1755 essay. In his capacity as a farmer, he wrote at least one critique about the negative consequences of price controls, trade restrictions, and subsidy of the poor. This is succinctly preserved in his letter to the London Chronicle published November 29, 1766, titled "On the Price of Corn, and Management of the poor."

=== Decision-making ===
In a 1772 letter to Joseph Priestley, Franklin laid out the earliest known description of the pro & con list, a common decision-making technique, now sometimes called a decisional balance sheet:

... my Way is, to divide half a Sheet of Paper by a Line into two Columns, writing over the one Pro, and over the other Con. Then during three or four Days Consideration I put down under the different Heads short Hints of the different Motives that at different Times occur to me for or against the Measure. When I have thus got them all together in one View, I endeavour to estimate their respective Weights; and where I find two, one on each side, that seem equal, I strike them both out: If I find a Reason pro equal to some two Reasons con, I strike out the three. If I judge some two Reasons con equal to some three Reasons pro, I strike out the five; and thus proceeding I find at length where the Ballance lies; and if after a Day or two of farther Consideration nothing new that is of Importance occurs on either side, I come to a Determination accordingly.

== Views on religion, morality, and slavery ==