Thomas Young - Natural philosopher

This year marks the 200th anniversary of Thomas Young's presentation of his pivotal essay on cohesion in fluids in which, among other important insights into capillarity, he stated in qualitative terms the concept of the Contact Angle. This, together with the Young/Laplace Equation (relating the surface tension to the pressure and radius of curvature) have formed the foundations of Capillarity theory and practice. It is interesting and timely to review briefly the life and achievements of this remarkable man who formally trained as a medical practitioner. A child prodigy brought up in the classics, with a command of numerous ancient and existing languages, he was a rare spirit driven to understand all physical phenomena about him; a polymath in an age of scientific enlightenment, he left an indelible mark in the humanities, sciences and technologies - in linguistics, egyptology, optics, the strength of materials, bridge and road construction, among many other fields. What interests us particularly today is that he always returned to the intriguing question of how particles are associated and held together to form the various states of matter. He invoked a model of matter being held together by short range attractive and repulsive forces acting between particles and gave plausible explanations of phenomena such as rigidity, elasticity and rupture, and what interests us in particular for this Meeting, because of his involvement in the hydrodynamics of blood flowing through capillary vessels, he made astonishing insights into basic Capillarity.