The following is an excerpt of Humphry Davy's "Researches on Nitrous Oxide," which recounts his unorthodox (at least by today's standards) methods of inductive research into the nature of laughing gas: :lol:

It occurred to me, that supposing nitrous oxide to be a stimulant of the common class, it would follow that the debility produced in consequence of excessive stimulation by a known agent, ought to be increased after excitement from nitrous oxide.
To ascertain whether this was the case, I made, on 23 December, at four p.m. the following experiment.

I drank a bottle of wine in large draughts in less than eight minutes. Whilst I was drinking, I perceived a sense of fulness in the head, and throbbing of the arteries, not unanalogous to that produced in the first stage of nitrous oxide excitement. After I had finished the bottle, this fulness increased, the objects around me became dazzling, the power of distinct articulation was lost, and I was unable to walk steadily. At this moment the sensations were rather pleasurable than otherwise, the sense of fulness in the head soon however increased so as to become painful, and in less than an hour I sunk into a state of insensibility.

In this situation I must have remained for two hours or two hours and a half.

I was awakened by a head-ache and painful nausea. The nausea continued even after the contents of the stomach had been ejected. The pain in the head every minute increased; I was neither feverish nor thirsty; my bodily and mental debility were excessive, and the pulse feeble and quick.

In this state I breathed for near a minute and a half five quarts of gas, which was brought to me by the operator for nitrous oxide; but as it produced no sensations whatever, and apparently rather increased my debility, I am almost convinced that it was from some accident, either common air, or very impure nitrous oxide.

As I recovered my former state of mind [following a later experiment in which Davy inhaled copious quantities of nitrous oxide], I felt an inclination to communicate the discoveries I had made during the experiment.

I endeavored to recall the ideas, they were feeble and indistinct; one colection of terms, however, presented itself: and with the most intense belief and prophetic manner, I exclaimed to Dr. Kinglake, "Nothing exists but thoughts! - the universe is composed of impressions, ideas, pleasures and pains!"