In the mid-18th century, Benjamin Franklin helped elucidate the nature of lightning and endorsed the protective value of lightning rods. And yet, a hundred years later, much of the public remained unconvinced. As a result, lightning continued to strike church steeples, ship masts, and other tall structures, causing severe damage.
Frustrated scientists turned to visual aids to help make their case for the lightning rod. The exploding thunder house is one example. When a small amount of gunpowder was deposited inside the dollhouse-size structure and a charge was applied, the house would either explode or not, depending on whether it was ungrounded or grounded. [For more on thunder houses, see “Tiny Exploding Houses Promoted 18th-Century Lightning Rods,.” IEEE Spectrum, 1 April 2023.]
Another visual aid for promoting lightning rods was an ingenious booklet by the British doctor and electrical researcher William Snow Harris. Published around 1861, Three Experimental Illustrations of a General Law of Electrical Discharge made the case for Harris’s invention: a lightning rod for tall-masted wooden ships. The rod was attached to the mainmast, ran through the hull, and connected to copper sheeting on the underside of the ship, thus dissipating any electricity from a lightning strike into the sea. It was a great idea, and it seemed to work. So why did the British Navy refuse to adopt it? I’ll get to that in a bit.
How to Illustrate the Principles of Lightning
The “experimental illustrations” in Harris’s 16-page pamphlet were intended to be interactive, each one highlighting a specific principle of conductivity. The illustrations were plated with gold leaf to mimic the conducting path of lightning. When the reader applied a charge to one end, the current charred a black course along the page. In the illustration at top, someone has clearly done this on the right hand side.
In the first experimental illustration in Harris’s book, the gold leaf is scattered haphazardly across the page. Linda Hall Library of Science, Engineering & Technology
The gold leaf in Harris’s first experimental illustration is placed haphazardly to show how electricity will follow the path of least resistance. If strong enough, the electricity will jump across small breaks to the closest adjacent metallic piece. Notably, pieces of gold that don’t lie along the path remain unaffected. Harris’s lesson here is that if there were a solid, uninterrupted line of metal that’s sufficiently isolated from other pieces—say, a lightning rod on a wooden ship’s mast—the current would follow that channel while sparing the rest.
The second experiment addresses a problem that was common in the days of tall ships: the rise and fall of the lightning rod as the jibs and rigging were adjusted according to the weather. Whereas a church steeple and its lightning rod remain fixed, a movable mast and the constantly changing rigging altered the configuration of the lightning rod. The experiment demonstrates that Harris’s design wasn’t affected by such changes. A charge wouldn’t dead-end and detonate midship just because a jib had been lowered. It would still follow the conductor that leads to the best exit for dissipation—that is, the ship’s bottom.
The second experiment was intended to show, in a stylized way, the effect of the lightning rod rising and falling as the jibs and rigging were adjusted.Linda Hall Library of Science, Engineering & Technology
The final experiment in the pamphlet, the one shown at top, takes direct aim at the preferred lightning conductor employed by the Royal Navy: a flexible cable or link of chains. The cable or chain was attached to the top of the foremast and then unfurled into the sea. But so deployed, it often got in the way, and most captains opted to store it rolled up somewhere on deck. Whenever a squall was spotted on the horizon, one unlucky sailor had to quickly haul the chain up the mast and attach it.
The experiment illustrates what would happen if the sailor were to accidentally come in contact with two points of a loose conductive cable during a lightning storm. Instead of following the cable, the discharge would course straight through him. As Harris wrote in the description, the poor seaman “would be probably destroyed.” Death was a clear risk for sailors on unprotected ships, just as it was for bell ringers in unprotected churches.
Mr. Thunder-and-Lightning Harris
William Snow Harris published Three Experimental Illustrations when he was about 70, and he died six years later. The booklet was his final salvo in a battle he had waged with the Royal Navy for decades.
Born in the port city of Plymouth, England, in 1791, Harris studied medicine in Edinburgh and then returned home, set up a practice, and was admitted to the Royal College of Physicians. In the 1810s, his fascination with lightning strikes and tall-masted wooden ships took hold. He began working on a shipborne lightning-rod system, perfecting it by 1820.
William Snow Harris (1791–1867) trained as a medical doctor but gave up his practice to focus on promoting his lightning rod for wooden ships. Plymouth Athenaeum
For the rest of his career, Harris tried to convince the Royal Navy to adopt it. He abandoned his medical practice and dove deeper into his studies of electricity. He presented papers at the Royal Society and wrote books on the nature of thunderstorms. An 1823 book on the effects of lightning on ships also featured his gold-leafed experimental illustrations, along with a vivid description of a lightning strike on an unprotected ship: “The main-top mast, from head to heel, was shivered into a thousand splinters….” Harris enlisted support for his system from leading scientists, such as Michael Faraday, Charles Wheatstone, and Humphry Davy. He eventually earned the nickname Mr. Thunder-and-Lightning Harris for his zealotry.
Despite his enthusiasm and the support of the Royal Society and other scientists, though, the navy declined to accept Harris’s proposal.
Harris continued to press his case. A well-publicized lightning strike on the U.S. packet ship New York in 1827 helped. Three days into its transatlantic journey, lightning struck at dawn. The “electrical fluid,” as it was then called, ran down the mainmast, bursting three iron hoops and shattering the masthead and cap. It entered a storeroom and demolished the bulkheads and fittings before following a lead pipe into the ladies’ cabin and fragmenting a large mirror. Elsewhere, it overturned a piano, split the dining table into pieces, and magnetized the ship’s chronometer as well as most of the men’s watches.
A lightning conductor wasn’t in place during the strike, but the crew raised the iron chain in the aftermath. Good thing they did. At 2:00 p.m., lightning struck the unfortunate New York again. As the American Journal of Science and Arts reported, the chain was “literally torn to pieces and scattered to the winds,” but it did its job and saved the ship, and no passengers were killed.
Subsequently, the admiralty agreed to conduct a pilot test of Harris’s system. Starting in 1830, the navy fitted the conductor onto 11 vessels, ranging in size from a 10-gun brig to a 120-gun ship of the line. The brig happened to be the HMS Beagle, which was about to set sail for a surveying trip of South America. After it returned five years later, one of its passengers, Charles Darwin, published an account that made the voyage famous. (His 1859 book, On the Origin of Species, was also based on his research aboard the Beagle.)
The HMS Beagle, made famous by Charles Darwin, was one of 11 British navy ships to be outfitted with Harris’s fixed lightning rods. Bettmann/Getty Images
During the expedition, the ship frequently encountered lightning and was struck at least twice. In August 1832, for instance, while the ship was anchored off Monte Video, Uruguay, First Lieutenant Bartholomew Sulivan described a strike that he witnessed while on deck: “The mainmast, for the instant, appeared to be a mass of fire, I felt certain that the lightning had passed down the conductor on that mast.”
Sulivan had previously been aboard the Thetis, whose foremast had been destroyed by lightning, so he was especially attuned to the destruction storms could cause. Yet on the Beagle, he wrote, “not the slightest ill consequence was experienced.” When Captain Robert FitzRoy made his report to the admiralty, he likewise endorsed Harris’s system: “Were I allowed to choose between masts so fitted and the contrary, I should decide in favor of those having Harris’s conductors.”
None of the 11 ships fitted with Harris’s system was damaged by lightning. And yet, the navy soon began removing the demonstration conductors and placing them in the scrap heap.
Numbers Don’t Lie
Not to be defeated, Harris turned to statistics, compiling a list of 235 British naval vessels damaged by lightning, from the Abercromby (26 October 1811, topmast shivered into splinters 14 feet down) to the Zebra (27 March 1838, main-topgallant and topmast shivered; fell on the deck; main-cap split; the jib and sails on mainmast scorched). Additionally, he cataloged the deaths of nearly 100 seamen and serious injury of about 250 others. During one particularly bad period of five or six years, Harris learned, lightning destroyed 40 ships of the line, 20 frigates, and 10 sloops, disabling about one-eighth of the British navy.
In December 1838, lightning struck and damaged a major warship, the 92-gun Rodney. Sensing an opportunity to make a public case for his system, Harris bypassed the admiralty and petitioned the House of Commons to review his claims. A Naval Commission appointed to do that wound up firmly supporting Harris.
Even then, the navy didn’t totally buy into Harris’s system. Instead, it allowed commanders to install it—if they petitioned the admiralty. Given how openly hostile the admiralty was toward Harris, I’m guessing many captains didn’t do that.
A Lightning Rod for Every British Warship
Finally, in June 1842, the admiralty ordered the use of Harris’s lightning rods on all Royal Navy vessels. According to Theodore Bernstein and Terry S. Reynolds, who chronicled Harris’s battle in their 1978 article “Protecting the Royal Navy from Lightning: William Snow Harris and His Struggle with the British Admiralty for Fixed Lightning Conductors” in IEEE Transactions on Education, the navy’s change of heart wasn’t due to better data or more appeals by Harris and his backers. It mostly came down to politics.
Bernstein and Reynolds offer three possible explanations as to why it took the admiralty more than two decades to adopt Harris’s demonstrably superior system. The first was ignorance. Although the scientific community was convinced early on by Harris, some people still believed that conductors attracted lightning, and they worried that lightning could ignite the stores of gunpowder on board.
A second argument was financial. Harris’s system was significantly more expensive than a simple cable or chain. In one 1831 estimate, the cost of Harris’s system ranged from £102 for a 10-gun brig to £365 for a 120-gun brig, compared to less than £5 for the simple cable. Sure, Harris’s system was effective, but was it more than 20 times as effective? Of course, the simple cable offered no protection at all if it was never deployed, as many captains admitted to.
John Barrow (1764–1848), second secretary to the Royal Navy Admiralty, was singularly effective at blocking the adoption of Harris’s lightning rod. National Portrait Gallery
But the ultimate reason for the navy’s resistance, argued Bernstein and Reynolds, was political. In 1830, when Harris seemed on the verge of success, the Whigs gained control of Parliament. In the course of a few months, many of Harris’s government supporters found themselves powerless or outright fired. It wasn’t until late 1841, when the Tories regained power, that Harris’s fortunes reversed.
Bernstein and Reynolds identified John Barrow, second secretary to the admiralty, as the key person standing in Harris’s way. Political appointees came and went, but Barrow held his office for over 40 years, from 1804 to 1845. Barrow managed the navy’s budget, and he apparently considered Harris a charlatan who was trying to sell the navy an expensive and useless technology. He used his position to continually block it. One navy supporter of Harris’s system called Barrow “the most obstinate man living.”
In Barrow’s defense, as Bernstein and Reynolds noted in their article, Harris’s system was brand new, and the navy already had an inexpensive and somewhat effective way to deal with lightning. Harris thus had to prove the value of his invention, and politicians had to learn to trust the results. That tension between scientists and politicians persists to this day.
Harris eventually proved victorious. By 1850, every vessel in the Royal Navy was equipped with his lightning rod. But the victory was fleeting. By the start of the next decade, the first British ironclad ship had appeared, and by the end of the century, all new naval ships were made of metal. Metal ships naturally conduct lightning to the surrounding water. There was no longer a need for a lightning rod.
Part of a continuing series looking at historical artifacts that embrace the boundless potential of technology.
An abridged version of this article appears in the March 2025 print issue as “The Path of Most Resistance.”
References
Finch Collins, assistant curator of rare books at the Linda Hall Library, in Kansas City, Mo., introduced me to the books of William Snow Harris. You should have seen his face when I asked if we could apply a battery to one of the lightning experiments in the book. You can see the books in person by visiting the library. Or you can enjoy fully scanned copies of Observations on the Effects of Lightning on Floating Bodies and Three Experimental Illustrations from your computer.
Theodore Bernstein of the University of Wisconsin–Madison and Terry S. Reynolds of Michigan Technological University wrote “Protecting the Royal Navy from Lightning—William Snow Harris and His Struggle with the British Admiralty for Fixed Lightning Conductors” for the February 1978 issue of IEEE Transactions on Education.
Many thanks to my colleague Cary Mock, a climatologist at the University of South Carolina who has an interest in extreme weather events throughout history. He has done amazing work re-creating paths of hurricanes based on navy logbooks. Cary patiently answered my questions about lightning and wooden ships and pointed me to additional resources, such as this fabulous “Index of 19th Century Naval Vessels.”
No comments:
Post a Comment