Robert Boyle
What happens when you squeeze air?
That time, that place
At Oxford, Boyle hired Robert Hooke as his assistant and built an air pump far better than Guericke's. With it he ran experiment after experiment: a bell inside the glass fell silent as the air went out, a candle guttered, a bird died.
Why this question
Everyone knows what happens when you squeeze air: it shrinks. The question is whether you can go further.
By how much? Squeeze twice as hard and what happens? Can that be answered with a number rather than a word?
What was found
He used a tube bent into a J. The short arm was sealed to trap air; mercury poured into the long arm compressed it. The more mercury, the shorter the trapped column.
He tabulated the height of mercury against the length of remaining air, entry by entry. A rule emerged: double the pressure and the volume halves. Multiply the two and you always get the same number.
A statement about nature had been written as a relation rather than a sentence.
Boyle also changed how experiments were written up: the apparatus drawn, the attempts that failed included, everything set down so that someone else could repeat it.
That air shrinks under pressure was as much as anyone knew
A table pairing mercury height against the volume of trapped air
Writing so that others can repeat you is the ancestor of the modern paper