“Languages are true analytical methods.”

Thus, while I thought myself employed only in forming a Nomenclature, and while I proposed to myself nothing more than to improve the chemical language, my work transformed itself by degrees, without my being able to prevent it, into a treatise upon the Elements of Chemistry.

We must trust to nothing but facts: These are presented to us by Nature, and cannot deceive. We ought, in every instance, to submit our reasoning to the test of experiment, and never to search for truth but by the natural road of experiment and observation.

It is not only by the pores of the skin that this aqueous emaciation takes place. A considerable quantity of humidity is also exhaled by the lungs at each expiration.

Vegetables are organized bodies that grow on the dry areas of the globe and within its waters. Their function is to combine immediately the four elements and to serve as food for animals.

Imagination, on the contrary, which is ever wandering beyond the bounds of truth, joined to self-love and that self-confidence we are so apt to indulge, prompt us to draw conclusions which are not immediately derived from facts.

It is impossible to disassociate language from science, To call forth a concept, a word is needed.

The whole art of making experiments in chemistry is founded on the principle: we must always suppose an exact equality or equation between the principles of the body examined and those of the products of its analysis.

Vegetation is the basic instrument the creator uses to set all of nature in motion.

I am young and avid for glory.

Perhaps; some day the precision of the data will be brought so far that the mathematician will be able to calculate at his desk the outcome of any chemical combination, in the same way, so to speak, as he calculates the motions of celestial bodies.

Sulfur, when burning, absorbs oxygen gas; the resulting acid is considerably heavier than the sulfur burned; its weight is equal to the sum of weights of the sulfur burned and the oxygen absorbed.

Nothing is born, nothing dies.

Mathematicians come to the solution of a problem by the simple arrangement of the data, and reducing the reasoning to such simple operations, to judgments so brief, that they never lose sight of the evidence that serves as their guide.

Diminish the mass of evils that afflict the human species, increase enjoyment and well-being. And even if the new routes opened up could prolong the average life of mankind by only a few hours, or even a few days, then the scientist, too could aspire.

The art of drawing conclusions from experiments and observations consists in evaluating probabilities and in estimating whether they are sufficiently great or numerous enough to constitute proofs. This kind of calculation is more complicated and more difficult than it is commonly thought to be.

Experiments upon vegetation give reason to believe that light combines with certain parts of vegetables, and that the green of their leaves, and the various colors of flowers, is chiefly owing to this combination.