Thales
3 of the 7 encyclopedias on this shelf carry an entry for Thales. Both are reproduced below, so you can see where they agree and where they differ.
Aiton's Encyclopedia (1910)
tha'lez (about 640-546 B. C.), a learned Greek. He is known as one of the seven wise men of Greece. He was the first of the Ionian natural philosophers. He considered water the basis of all things, the universal principle of nature. He established the length of the year at 365 days. He predicted an eclipse of the sun for May 28, 585 B. C. He is considered the originator of several geometrical theorems. he discovered the truth that each angle inscribed in a semicircle is a right angle. This he regarded so important a mathematical truth that it is said he sacrificed an ox to the immortal gods. He is also said to have computed the height of an Egyptian pyramid by thrusting a stick into the ground. The shadow of this stick and the height of his stick, and the shadow of the pyramid, gave him three terms of a proportion, whereby he found the fourth term, namely the desired height of the pyramid. See Euclid ; Pythagoras ; Alchemy
Collier's New Encyclopedia (1921)
the earliest of the Greek philosophers, called the father of philosophy; born in Miletus 640 b. c. He was the founder of the Ionic school, one of the chief sources of Grecian philosophy. He visited Egypt for instruction in the sciences professed by the priesthood. Besides abstract philosophy, he studied geometry and astronomy, and tradition credits him with predicting a eclipse. His ancient biographers mention among his services to astronomy a calculation of the length of the year, and of the interval between solstices and equinoxes. He left nothing in writing. He died about 550. solar
1000 Classical Characters (1900)
One of the seven wise men of Greece, born at Miletus in Ionia . His discoveries in astronomy were great, and he was the first who calculated with accuracy a solar eclipse. He died about 548 years before the Christian era. 2026 Editor's Note: While this text credits Thales with the first accurate calculation of a solar eclipse, modern scholars remain skeptical of how he could have achieved such a prediction with the tools of his era. The event, often identified as the eclipse of May 28, 585 BC, reportedly occurred during a battle between the Medes and the Lydians, leading to an immediate truce. Beyond astronomy, Thales is regarded as the first philosopher in the Greek tradition for shifting from mythological explanations to natural philosophy, famously theorizing that all nature originated from water. (Ed: BR 2026-07-18)