﻿TRANSACTIONS 
  

  

  OF 
  Till! 
  

  

  ROYAL 
  SOCIETY 
  

  

  OF 
  

  

  EDINBURGH. 
  

  

  VOL. 
  XX. 
  

  

  EDINBURGH 
  : 
  

  

  PUBLISHED 
  BY 
  ROBERT 
  GRANT 
  & 
  SON, 
  82 
  PRINCES 
  STREET. 
  

  

  AND 
  WILLIAMS 
  & 
  NORGATE, 
  14 
  HENRIETTA 
  STREET, 
  COVENT 
  GARDEN, 
  LONDON. 
  

  

  MDCCCLIII. 
  

  

  