Historic molecular model on show in Edinburgh
The first three-dimensional model of a chemical structure made out of knitting needles and balls of wool, has gone on display in Edinburgh.
The molecular model of common salt was created by Scots-born chemist Prof Alexander Crum Brown in 1883.
Knitting enthusiast Prof Crum Brown built the model while at Edinburgh University.
It is on display at the university's School of Chemistry to mark the UNESCO International Year of Chemistry.
Prof Crum Brown was a pioneer in understanding how chemical atoms are physically arranged to form molecular structures.
His love of knitting inspired the model and paved the way for the ball-and-stick structures still used by chemists today, alongside computer graphics, molecular movies and three-dimensional animations.
The professor was born in Edinburgh in 1838. As a child he created a weaving machine and retained a life-long interest in knots and complex knitting.
He graduated from the University of Edinburgh in 1861 and returned in 1863 as a chemistry lecturer. He became chair of chemistry in 1869, a post he held until retirement in 1908.