Image copyright RBS Image caption RBS chief executive Ross McEwan showed off the new design in Edinburgh

The Royal Bank of Scotland is to issue its first polymer £10 note to the public on 4 October.

The new note features images of Scottish mathematician and astronomer Mary Somerville, her hometown of Burntisland in Fife, and two otters.

The material includes a variety of new security features which the bank said makes them "difficult to counterfeit but easy to authenticate".

For the first time, the note includes braille to help the visually impaired.

The bank also announced that the face of its polymer £20 note, which is not expected to enter circulation until 2020, will feature Glasgow philanthropist and entrepreneur Catherine Cranston.

Who is Mary Somerville?

By BBC Scotland Science correspondent Kenneth Macdonald

Image copyright James R. Swinton Image caption Scottish scientific writer Mary Somerville (nee Fairfax) (1780 - 1872)

Mary Fairfax Somerville was a mathematician, geographer and astronomer, who was born in 1780 in Jedburgh but her childhood home was at Burntisland in Fife.

Her parents tried to stop her studying because they thought it would kill her. Her sister had died and they thought studying was to blame.

But Mary ploughed on and carried out detailed and highly-accurate studies of the solar system.

She was so accurate that she noticed a wobble in the orbit of Uranus and suggested there could be another planet out there.

She was right. It was the planet Neptune.

Jointly with Caroline Herschel, she became the first female member of the Royal Astronomical Society.

Mary was also a huge advocate of women's rights, votes for women and women in education, which is why the formerly women-only Somerville College, Oxford, was named after her soon after her death in 1872.

Its alumni include former Indian prime minister Indira Ghandi and Margaret Thatcher, among others.

'Public influence'

The new £10 note is 15% smaller than the paper ones currently in circulation. It follows the bank's polymer £5 note, which features Scottish novelist and poet Nan Shepherd, and came into circulation in 2016.

RBS chief executive Ross McEwan said the bank felt that their notes had value beyond the figure printed on them, and were a "symbol which lives in people's pockets and touches everyday lives".

He said: "It has been 30 years since we produced a new £10 note, and we wanted the public to help influence the design. They helped influence our theme of 'fabric of nature' and helped us consider the impact Mary Somerville has had on our understanding of the world in which we live.

"It is fitting that our most advanced note yet will carry her portrait."

Image copyright Royal Bank of Scotland

A moon diagram taken from Somerville's book Mechanism of the Heavens appears when the note is viewed under UV light.

Words from the Scottish poet Norman MacCaig also feature.

Bank of Scotland also has a polymer £10 note entering circulation, featuring the image of Sir Walter Scott, while Clydesdale Bank's version, featuring Robert Burns, comes out on 21 September.