Telling the time by smell - a unique invention of the ancients.

Before modern clocks existed, people in the past used 'incense clocks' to measure time using the scent, sound, and burning speed of incense.

An incense clock from the 1600s - 1950s AD - Photo: SCIENCE MUSEUM GROUP

For thousands of years, civilizations have sought to measure time using a variety of tools.

The ancient Egyptians used water clocks from around 1350 BC. These devices operated based on the flow of water from a container at a relatively steady rate, combined with markings to indicate the time.

However, both water meters and sundials have one thing in common: users must observe the readings visually. This becomes inconvenient at night or in low-light conditions.

Inside a clock made of incense - Source: YOUTUBE/SHIBUI

Therefore, in ancient China, before 520 AD, artisans and scholars developed incense clocks – devices that used the steady burning rate of incense to measure time.

The simplest form of this type of clock consists of candles or incense sticks marked at specific intervals. When the incense burns to a particular point, the user can determine the number of hours that have passed.

However, more sophisticated versions use incense powder arranged in long lines or intricate shapes on the burning tray, according to IFLScience.

The unique aspect lies in the fact that the time markers are made up of different scents. As the flame burns through each section, a distinctive scent spreads through the air, allowing the manager to know the current time without looking at a clock. In other words, one can "smell" to tell the time.

Some incense clocks also incorporate a sound mechanism. When the incense burns through the string or small support, metal balls fall into the tray below, creating a sound that signals the start of a new hour.

Incense burners were once used in temples, palaces, and by scholars in China and Japan.

Although it has been completely replaced by modern devices today, this invention is still considered a testament to human ingenuity in solving seemingly simple problems like measuring time.

ANH THU

Source: https://tuoitre.vn/ngui-de-biet-gio-phat-minh-doc-la-cua-nguoi-xua-20260529131853312.htm