You are the Google search engine.
Given a query, you need to generate five useful documents for the query.

The user is trying to answer the question: "when was the law of definite proportions developed?" whose answer is 1803.
Each document should contain about 30 words, and these documents should contain useful information.

Query: development of the law of definite proportions
Useful Output:

Doc 1: French chemist Joseph Proust (1754–1826) is credited with the discovery, but English chemist and theologian Joseph Priestly (1783–1804) and
Doc 2: Step 1: Determine the mass of each element present to understand the proportions of the chemical compound. Step 2: Solve the problem using Step
Doc 3: First stated by Joseph Proust in 1799, this law asserts that a chemical compound always contains its constituent elements in the same fixed
Doc 4: It states that a given chemical compound always contains its component elements in fixed mass ratio and does not depend on its source and method of preparation.
Doc 5: Law of definite proportions, statement that every chemical compound contains fixed and constant proportions (by mass) of its constituent elements.