Show & Tell: The Lamp That Saved Coal Miners' Lives

Paul Wilkinson

Coal, as the chemist Sir Humphry Davy observed in his 1818 book describing the development of this Davy Safety Lamp, was at the heart of much of early 19th-century England’s industrial progress. “Essential in affording warmth and preparing food, it yields a sort of artificial sunshine, and in some measure compensates for the disadvantages of our climate,” he wrote. “By means of it, metallurgical processes are carried on, and the most important materials of civilized life furnished … Not only manufactories and private houses, but even whole streets are lighted by its application.”

Yet this wonderful material needed to be mined by men (and boys) who were taking great risks with their lives. Ironically enough, given coal’s light-giving properties, one of their major problems as workers was illumination. Miners carrying lamps could run into pockets of methane gas, then often called firedamp, which would explode when it came into contact with the flame. (An 1883 glossary of mining terms tells us that miners called cavities in coal seams “bags of foulness,” an epithet that gives some sense of their dread of such spots.)

In his book On the Safety Lamp for Coal Miners, Davy describes—in a deliberately dry fashion intended to forestall morbid curiosity—the effects of such explosions:

The phenomena are always of the same kind. The miners are either immediately destroyed by the explosion, and thrown with the horses and machinery through the shaft into the air, the mine becoming as it were an enormous piece of artillery, from which they are projected; or they are gradually suffocated, and undergo a more painful death from the carbonic acid and azote remaining in the mine after the inflammation of the fire damp; or what, though it appears the mildest, is perhaps the most severe fate, they are burnt or maimed, and often rendered incapable of labor and of healthy enjoyment for life.

In 1812 a firedamp explosion in the Felling mine, in northeast England near Newcastle, killed 92 workers. In the aftermath, a concerned clergyman asked Davy, who was employed by the Royal Institution as a chemist, experimenter, and public educator, and who had by that point in his career gained both fame and a knighthood, to find a safer way to illuminate the mines.

Davy experimented on the lamp in his London laboratory throughout the fall of 1815. Given the contemporary level of understanding of the action of flame, his experiments were quite dangerous. He eventually arrived at a design that seems, in retrospect, obvious: a flame surrounded by iron wire gauze, which would allow light out, but absorb the heat that caused the explosions.

Image credit: Paul Wilkinson

Davy’s lamp was widely adopted after successful tests in January 1816. Although he was urged to patent the invention, he decided not to profit off of the design. Even though he didn’t claim intellectual priority, he found himself drawn into a fight with engineer George Stephenson, who had invented a different, less effective kind of safety lamp at the same time, and needed to prove that he had come up with the idea first. Davy eventually won that battle, but Stephenson was to go on to make a different kind of mark on the industrial landscape by inventing and perfecting the first steam-powered locomotive.  

Biographer Richard Holmes writes that despite his refusal to patent the lamp, Davy was nonetheless “hugely proud of his achievement, and was never modest about it.” The chemist received a medal from the Royal Society and was made a baronet; he even “designed his own coat of arms, showing the safety lamp encircled with a Latin motto which announced: ‘I Built The Light Which Brings Safety.’”

Afternoon Map
The Most Searched Shows on Netflix in 2017, By State

Orange is the New Black is the new black, at least as far as Netflix viewers are concerned. The women-in-prison dramedy may have premiered in 2013, but it’s still got viewers hooked. Just as they did in 2017, took a deep dive into Netflix analytics using Google Trends to find out which shows people in each state were searching Netflix for throughout the year. While there was a little bit of crossover between 2016 and 2017, new series like American Vandal and Mindhunter gave viewers a host of new content. But that didn’t stop Orange is the New Black from dominating the map; it was the most searched show in 15 states.

Coming in at a faraway second place was American Vandal, a new true crime satire that captured the attention of five states (Illinois, Kansas, Massachusetts, Minnesota, and Wisconsin). Even more impressive is the fact that the series premiered in mid-September, meaning that it found a large and rabid audience in a very short amount of time.

Folks in Alaska, Colorado, and Oregon were all destined to be disappointed; Star Trek: Discovery was the most searched-for series in each of these states, but it’s not yet available on Netflix in America (you’ve got to get CBS All Access for that, folks). Fourteen states broke the mold a bit with shows that were unique to their state only; this included Big Mouth in Delaware, The Keepers in Maryland, The OA in Pennsylvania, GLOW in Rhode Island, and Black Mirror in Hawaii.

Check out the map above to see if your favorite Netflix binge-watch matches up with your neighbors'. For more detailed findings, visit

Afternoon Map
Monthly Internet Costs in Every Country

Thanks to the internet, people around the world can conduct global research, trade tips, and find faraway friends without ever leaving their couch. Not everyone pays the same price for these digital privileges, though, according to new data visualizations spotted by Thrillist.

To compare internet user prices in each country, cost information site created a series of maps. The data comes courtesy of English market research consultancy BDRC and, which teamed up to analyze 3351 broadband packages in 196 nations between August 18, 2017 and October 12, 2017.

In the U.S., for example, the average cost for internet service is $66 per month. That’s substantially more than what browsers pay in neighboring Mexico ($27) and Canada ($55). Still, we don’t have it bad compared to either Namibia or Burkina Faso, where users shell out a staggering $464 and $924, respectively, for monthly broadband access. In fact, internet in the U.S. is far cheaper than what residents in 113 countries pay, including those in Saudi Arabia ($84), Indonesia ($72), and Greenland ($84).

On average, internet costs in Asia and Russia tend to be among the lowest, while access is prohibitively expensive in sub-Saharan Africa and in certain parts of Oceania. As for the world’s cheapest internet, you’ll find it in Ukraine and Iran.

Check out the maps below for more broadband insights, or view’s full findings here.

Map of Internet costs in each country created by information site

Map of Internet costs in each country created by information site

Map of Internet costs in each country created by information site

Map of Internet costs in each country created by information site

Map of Internet costs in each country created by information site

[h/t Thrillist]


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