How Do They Dye the Chicago River Green for St. Patrick's Day?

iStock.com/stevegeer
iStock.com/stevegeer

It wouldn’t be a St. Patrick’s Day celebration in the Windy City without 400,000 spectators crowding the banks of the Chicago River to “ooh” and “aah” at its (temporarily) emerald green tinge. But how do officials turn the water green?

First, a bit of history: The dyeing tradition became an annual thing nearly 60 years ago, in 1962, but its real origins go back even further. In the early days of his administration as Mayor of Chicago, Richard J. Daley was a man on a mission to develop the city’s riverfront area. There was just one problem: The river itself was a sewage-filled eyesore. In order to get to the bottom of the city’s pollution problem and pinpoint the exact places where waste was being discarded into the waterway (and by whom), Daley authorized the pouring of a special green dye into the river that would allow them to see exactly where dumping was occurring.

Fast-forward to late 1961 when Stephen Bailey—part of the Chicago Journeymen Plumbers Local, the city’s St. Patrick’s Day Parade chairman, and a childhood friend of Daley’s—witnessed a colleague’s green-soaked coveralls following a day of pouring Daley’s dye into the Chicago River. That gave Bailey an idea: If they could streak the Chicago River green, why not turn it all green?

Three months later, revelers got their first look at an Ecto Cooler-colored river when the city poured 100 pounds of the chemical into the water. They got a really good look, too, as the river remained green for an entire week.

Over the next several years, the same practice was repeated, and again it was carried out by the Plumbers Local. The only difference was that the amount of dye used was cut in half over the next two years until they finally arrived at the magic number: 25 pounds of dye = one day of green water.

Unfortunately, the dye that was intended to help spot pollution was an oil-based fluorescein that many environmentalists warned was actually damaging the river even more. After fierce lobbying, eco-minded heads prevailed, and in 1966 the parade organizers began using a powdered, vegetable-based dye.

While the exact formula for the orange powder (yes, it's orange until it's mixed with water) is kept top-secret—in 2003 one of the parade organizers told a reporter that revealing the formula would be akin to “telling where the leprechaun hides its gold”—there are plenty of details that the committee lets even non-leprechauns in on.

The dyeing process will begin at 9 a.m. on the morning of the parade—which this year is Saturday, March 16 (it's always held on a Saturday) when six members of the local Plumbers Union hop aboard two boats, four of them on the larger vessel, the remaining two on a smaller boat.

The larger boat heads out onto the water first, with three members of the crew using flour sifters to spread the dye into the river. The smaller boat follows closely behind in order to help disperse the substance. (The best place to catch a glimpse is from the east side of Michigan Avenue, or on Upper and Lower Wacker Drive between Michigan Avenue and Columbus Drive.)

Approximately 45 minutes later, voila, the Chicago River is green—but don’t expect it to stay that way. These days, the color only sticks around for about five hours. Which is roughly the same amount of time it takes to get a perfectly poured pint of Guinness if you venture out to an Irish pub on St. Patrick’s Day.

A version of this article first ran in 2017.

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Why Are Barns Often Painted Red?

iStock/Ron and Patty Thomas
iStock/Ron and Patty Thomas

Beginning with the earliest American settlements and continuing into the 18th century, most barns weren't painted at all. Early American barn builders took sun exposure, temperature, moisture, wind, and water drainage patterns into account when placing and building barns, and they seasoned the wood (that is, they reduced the moisture content) accordingly. The right type of wood in the right environment held up fine without any paint.

Toward the end of the 1700s, these old-school methods of barn planning and building fell by the wayside. People sought a quicker, easier fix for preserving their barns—a way to coat and seal the wood to protect it from sunlight and moisture damage. Farmers began making their own coating from a mix of linseed oil (a tawny oil derived from the flax seeds), milk, and lime. It dried quickly and lasted a long time, but it didn't really protect the wood from mold and wasn't quite like the "barn red"we know today—it was more of a burnt orange, really.

Turning Red

The problem with mold is that it decays wood and, in large quantities, can pose health risks to people and animals. Rust, it turns out, kills mold and other types of fungi, so farmers began adding ferrous oxide (rusted iron) to the linseed oil mix. A little bit of rust went a long way in protecting the wood, and it gave the barn a nice red hue.

By the late 19th century, mass-produced paints made with chemical pigments became available to most people. Red was the least expensive color, so it remained the most popular for use on barns, except for a brief period when whitewash became cheaper and white barns started popping up. (White barns were also common on dairy farms in some parts of Pennsylvania, central Maryland, and the Shenandoah Valley, possibly because of the color's association with cleanliness and purity.)

Throughout Appalachia (a historically poorer region), many barns went unpainted for lack of money. In the tobacco regions of Kentucky and North Carolina, black and brown barns were the norm, since the dark colors helped heat the barn and cure tobacco.

Today, many barns are still painted the color traditionally used in a given region, with red still dominating the Northeast and Midwest.

Have you got a Big Question you'd like us to answer? If so, send it to bigquestions@mentalfloss.com.

This story was updated in 2019.

Is There An International Standard Governing Scientific Naming Conventions?

iStock/Grafissimo
iStock/Grafissimo

Jelle Zijlstra:

There are lots of different systems of scientific names with different conventions or rules governing them: chemicals, genes, stars, archeological cultures, and so on. But the one I'm familiar with is the naming system for animals.

The modern naming system for animals derives from the works of the 18th-century Swedish naturalist Carl von Linné (Latinized to Carolus Linnaeus). Linnaeus introduced the system of binominal nomenclature, where animals have names composed of two parts, like Homo sapiens. Linnaeus wrote in Latin and most his names were of Latin origin, although a few were derived from Greek, like Rhinoceros for rhinos, or from other languages, like Sus babyrussa for the babirusa (from Malay).

Other people also started using Linnaeus's system, and a system of rules was developed and eventually codified into what is now called the International Code of Zoological Nomenclature (ICZN). In this case, therefore, there is indeed an international standard governing naming conventions. However, it does not put very strict requirements on the derivation of names: they are merely required to be in the Latin alphabet.

In practice a lot of well-known scientific names are derived from Greek. This is especially true for genus names: Tyrannosaurus, Macropus (kangaroos), Drosophila (fruit flies), Caenorhabditis (nematode worms), Peromyscus (deermice), and so on. Species names are more likely to be derived from Latin (e.g., T. rex, C. elegans, P. maniculatus, but Drosophila melanogaster is Greek again).

One interesting pattern I've noticed in mammals is that even when Linnaeus named the first genus in a group by a Latin name, usually most later names for related genera use Greek roots instead. For example, Linnaeus gave the name Mus to mice, and that is still the genus name for the house mouse, but most related genera use compounds of the Greek-derived root -mys (from μῦς), which also means "mouse." Similarly, bats for Linnaeus were Vespertilio, but there are many more compounds of the Greek root -nycteris (νυκτερίς); pigs are Sus, but compounds usually use Greek -choerus (χοῖρος) or -hys/-hyus (ὗς); weasels are Mustela but compounds usually use -gale or -galea (γαλέη); horses are Equus but compounds use -hippus (ἵππος).

This post originally appeared on Quora. Click here to view.

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