Archimedes and the Surface of any Fluid

In the 3rd century BCE, Archimedes of Syracuse wrote what we now call the Archimedes’ principle in his book “On Floating Bodies” using the spherical Earth model.

Flat-Earthers like to misuse Archimedes’ principle as if it supports their claim that Earth is flat. In particular, they abuse Archimedes’ principle as if it is a competing explanation against gravity. In reality, Archimedes and other Greek scientists at the time already knew Earth is a sphere, and he explicitly mentioned it in his writings.

Archimedes wrote the Archimedes’ Principle in his writing “On Floating Bodies,” which is separated into two books. The first part explains what we call now the Archimedes’ Principle.

He divided his explanation into several propositions. In his second proposition he explained:

“The surface of any fluid at rest is the surface of a sphere whose center is the same as that of the earth.”

Then he continued to explain his principle in the following propositions using the mentioned spherical Earth model.


Archimedes wrote his books in ancient Greek. The following is several English translations of his proposition discussed here.

“Archimedes” by Eduard Jan Dijksterhuis:

“The surface of any fluid which is so located that it remains motionless will have the form of a sphere which has the same centre as the earth.”

“The Works of Archimedes” by Sir Thomas Little Heath:

“The surface of any fluid at rest is the surface of a sphere whose centre is the same as that of the earth.”

“The Genius of Archimedes” by S. A. Paipetis & Marco Ceccarelli:

“The surface of any liquid at rest is a spherical surface whose center point is at the center of the earth.”

We can conclude there’s practically a consensus, and we can rule out translation errors in this case.