33
/
AIzaSyB4mHJ5NPEv-XzF7P6NDYXjlkCWaeKw5bc
November 30, 2025
2147129
179598
2
Public Timelines
FAQ

jan 27, 1754 - Joseph Louis Proust The Law of Definite Proportions, sometimes called The Law of Constant Composition, states that a chemical compound always contains exactly the same proportion of elements by mass.

Added to timeline:

Date:

jan 27, 1754
Now
~ 271 years ago