Strange but true story: Scientists used leeches to predict the weather?

In the 1800s, scientists used leeches placed in a glass jar to predict the weather for the day.

In the old days, people had many different ways to forecast the weather of the day based on the characteristics of nature, including plants, animals, insects, etc. Because these are quite sensitive to the weather. The weather should be able to predict the upcoming events in advance. For example, when frogs cry loudly or birds fly in flocks to the nest, it is a sign of an upcoming thunderstorm.

Strange but true story: Scientists used leeches to predict the weather?
Leeches were used to forecast the weather in 1800 by doctor George Merryweather.

Even in the 1800s, people even used leeches to forecast the weather of the day. It was Dr. George Merryweather, a 19th century English doctor who discovered this interesting way of forecasting.

As a doctor, Merryweather has many opportunities to interact with creatures, including leeches. And after a while observing leeches, Merryweather realized that leeches also change their “lifestyle” based on the weather.

Specifically, when the weather is normal, such as a sunny day, the leeches will just stay at the bottom of a glass jar. But just a few hours before a thunderstorm hit, the leeches immediately emerged from the water and began to get agitated. They even curled up into balls and so on after feeling the storm pass. After going through a rough time, the discs will stretch out and relax again.

It was the computer leeches’ quick reflexes that gave Merryweather the ideas. He built a device called “Atmospheric Electromagnetic Telegraph practiced by Animal Instinct” , roughly translated as an animal-based weather forecasting device . It has the ability to predict storms and many other weather phenomena early.

This weather forecaster is made up of 12 glass bottles, each with a live leech inside and poured water about 4cm high. At the neck of the bottle is attached a baleen whale horn. The horn plate is attached to a small hammer that knocks the metal bell to warn.

Strange but true story: Scientists used leeches to predict the weather?
Weather-based experiment with leeches.

When a thunderstorm is detected early, the leeches will move out of the water and climb up to the mouth of the bottle. However, they will be blocked at the neck of the bottle. Even so, when the leeches struggle to get out of the bottle, they can push the horns off and make a ringing sound. Merryweather can rely on the number of consecutive bells ringing to predict the storm.

The British doctor took about a year to perfect the device and sent a letter to the Philosophical Society to introduce the weather forecaster using leeches. He even lobbied the authorities to use the device on sea voyages.

Unfortunately, the UK used an invention called “storm glass “, a special liquid-based meteorological instrument introduced in 1750, instead of a weather forecaster. Merryweather’s leeches.

Strange but true story: Scientists used leeches to predict the weather?
A leech weather forecast device on display at a museum in the UK.

Since then, Merryweather’s work has passed into the past. There is still a replica of the leech weather forecaster on display at the Whitby Town Museum in the UK.