This interesting piece of sculpture sits on the exterior of the Central Library on George IV Bridge. My interpretation of it is that it shows Caledonia ('Scotland' - note the tartan plaid) in the middle, with farmers on either side (note the sickle on the left and plough on the right). Look closely and you can see the kilt and beautiful sporran on the left-hand farmer.
I think the motto means: "Always up in arms, now also industrious" which I guess points at a desire to move away from militarism in the Highlands towards peaceful and productive farming. Now a library, this part of the building was once the Highland and Agricultural Institute.