Joseph Priestley

His History and Present State of Electricity (1767) surveyed the field and added his own experiments, and it led to his election to the Royal Society.

He identified at least eight new gases, devised a way to make carbonated water, and set out hundreds of experiments in the six-volume Experiments and Observations on Different Kinds of Air (1774-1786).

In 1774 he isolated the gas now called oxygen, which he named dephlogisticated air, and showed it to Lavoisier, who built the new chemistry on it.

After finding that a candle burned strongly in the new air from heated mercuric oxide, he put mice in it and then breathed it himself, noting that only two mice and he had so far had the privilege.

This is consistent with a researcher who followed an unexpected result with further tests on whatever he could try, including himself. Curiosity

In 1797, when the scientific community had dismissed phlogiston, he published The Doctrine of Phlogiston Established, and he still held the view when he died.

This is consistent with holding a framework against the weight of contemporary evidence, a stance historians read as both tenacious and costly. Belief Updating

After Lavoisier's Traite of 1789, the Hexagon article says, Priestley's science turned from new discoveries to rearguard actions defending phlogiston.

This is consistent with a researcher whose output shifted from exploring new phenomena to defending an established position once the field moved against him. Belief Updating