When I saw this stone I was reminded that today is Michaelmas when traditionally the harvest was expected to have been gathered in.   It is one of five stone inscribed in Latin on the wall of The Museum of Edinburgh (formerly the Huntly House Museum) in the Canongate. More information and two of the stones are here..
It has a picture of wheat sheaves and the words SPES ALTERA VITAE which can be interpreted as 'Hope for a better life'.  In past times a good wheat harvest helped to ensure that there was plenty of bread to keep them alive throughout the winter and so wheat sheaves became associated with a successful harvest and healthy life.