tea:n^sactions 



OF THE 



ROYAL SOCIETY 



OP 



EDINBURGH. 



VOL. XVL 



EDINBURGH : 



PUBLISHED BY ROBERT GRANT & SON, 82 PRINCE'S STREET ; AND 



WILLIAMS & NORGATE, 14 HENRIETTA STREET, 



COVENT GARDEN, LONDON. 



MDCCCXLIX. 



