Here is an excerpt:

When the 1860 conference began, chemistry was in a total state of disarray. Although most chemists believed in atoms and molecules, nobody could agree on molecular formulas. Even simple molecules such as water were hotly debated: Most leading chemists at the time claimed that water’s molecular formula was OH, and a minority argued that it was H₂O. More complex molecules were an even bigger battleground: At least 19 different representations of acetic acid were being used in textbooks of that era.

The motivation for the conference is obvious. Read the entire article to understand its significance.