1. Chaos and Law outside the Laboratory (1640-1658) The English Civil Wars took place in this period(1642-1648) Irish Rebellion led by Earl of Tyrone begins in 1641 Charles I executed (1649) Oliver Cromwell sent to Dublin (1649) Not a good environment for scientific studies to take place Cromwell dies in 1658

2. Robert Boyle (1627-1691) [seventh son of the Earl of Cork] Like van Helmont, he did not believe in the 4 “element” ideas of Aristotle Boyle determined to investigate Torricelli’s vacuum….but on a larger scale. His student, Robert Hooke, built him a pump for this purpose (ca.1658)

3. Touching the Spring of Air (1659-1662) Hooke’s Law was published in 1660. It relates the extension of a mechanical spring to the applied load. Boyle was convinced that air was comprised of individual “corpuscles”. He reasoned that air would spring (i.e.be elastic) thereby resisting compression and expanding to fill the available space Did he induct that the corpuscles might act as individual “springs” ?

4. Richard Townley and Henry Power (1659-1660) Placed equal volumes of air and mercury in a Torricelli U-tube that was inverted into a dish of mercury They noted the expansion of the included air at different altitudes on Pendle Hill near Burnley. Demonstrated that 'Mountain Ayr' reduced in volume when carried to the bottom of the hill, while 'Valley Ayr' increased at the top Concluded that an inversely proportional relationship existed between gas pressure and volume. Wrote to Boyle accordingly

5. Townley and Power’s Law? (aka Boyle’s Law) Boyle performed similar experiments in his laboratory and published them in 1662 Power became an elected member of the newly created Royal Society

6. Philosophical Transactions The ancient traditions of: Natural Philosophy: “See and Think”. (How does it happen?) are replaced by Experimental Philosophy: “Observe and Test”. (Why does it happen?)

7. Art of the Time Rembrandt’s: “The NightWatch” (1642)

8. Discovery: 1640-1665 A variety of “gases” existed A vacuum could be created The Barometer was invented The concept that air had a weight was proved The “elasticity of air” idea was put forward The inverse relationship between pressure and volume of air was measured and established A time for Experimental Philosophy