XO 
LYON PLAYFAIR, C.B, LL.D., &C,, 
EMERITUS PROFESSOR OF CHEMISTRY IN THE UNIVERSITY OF EDINBURGH, 
AND MEMBER OF PARLIAMENT FOR THE UNIVERSITIES OF 
EDINBURGH AND ST ANDREWS, 
THIS WORK 
IS MOST RESPECTFULLY INSCRIBED, 
IN ADMIRATION OF HIS EMINENT GIFTS AS A TEACHER, 
AND NO LESS SO AS AN ACKNOWLEDGMENT 
OF HIS ENERGETIC EFFORTS 
TO PROMOTE THE POPULAR DIFFUSION 
OF SCIENTIFIC INSTRUCTION. 
