Subject: biography, technology and manufacturing
British civil engineer who rebuilt the Eddystone lighthouse in 1759 and was also greatly influential in directing the scientific research that was being carried out in the mid-18th century. It was he who first adopted the term ‘civil engineer’ in contradistinction to the fast-growing number of mililtary engineers graduating from the military colleges.
Smeaton was born of Scottish ancestry in Austhorpe, near Leeds on 8 June 1724. He was encouraged to practise law, and after a good elementary education he served in his father's firm of solicitors. Later he went to London for further training, but his natural inclination for mechanical science led him to leave law and become a maker of scientific instruments.
He soon introduced many technical innovations - one of which was a novel instrument with which he was able to measure and study the expansion characteristics of various materials. From 1756 to 1759 he was engaged in the rebuilding of the Eddystone lighthouse in the English Channel. He was also a consultant in the field of structural engineering, and from 1757 onwards he was responsible for many engineering projects including bridges, power stations operated by water or wind, steam engines, and river and harbour facilities.
He was a charter member of the first professional engineering society, the Society of Civil Engineers (founded in 1771), which, after his death, became known as the Smeatonian Society. He was a fellow of the Royal Society and, in 1759, received its Copley Medal. He died on 28 October 1792, at Austhorpe.
Although Smeaton's best known achievement was the rebuilding of Eddystone, his main contribution to engineering was his innovative ability to combine engineering with applied science. His work on water wheels and windmills served to underline the importance of scientific research to practical engineering problems. It was his own research work that led him to question the relative efficiency of the then firmly established undershot water wheel (which operates through the action of the flow of water against blades in the wheel) and the overshot wheel (which is operated by water moving the wheel by the force of its weight).
Experimenting with models, Smeaton showed that overshot wheels were twice as efficient as undershot ones. He went further and speculated on the cause of this difference in efficiency. From his experiments, he concluded that the loss of ‘mechanic power’ in the undershot wheel was caused by turbulence, which he described as the loss of power by water and other non-elastic bodies in changing their ‘figure’ in consequence of their ‘stroke’. Thus, only part of their original power is communicated when acting by impulse or collision.
In 1759 Smeaton presented his important paper to the Royal Society, ‘An experimental enquiry concerning the natural power of water and wind to turn mills and other machines depending on a circular motion’. This paper was followed by two others, one on the necessary mechanical power to be employed in giving different degrees of velocity to heavy bodies from a state of rest, and the other on some ‘fundamental experiments upon the collision of bodies’.
Smeaton's work, with its emphasis on scientific investigation into practical engineering problems, provided one of the first examples of the interdependence of engineering and applied science. This led to other designers adopting his approach. (One early result of this was that the undershot water wheel was abandoned as uneconomical.) It also lent a sense of urgency to the recurrent controversy raging at the time over the measure of force, in the discussions of which Smeaton's own research findings played a prominent role.
Later on in life Smeaton performed extensive tests on the experimental steam engine of Thomas Newcomen, which led to significant improvements in its design and efficiency.