g PREFACE. 



Prof. J. W. Cliickering, jr., of the Columbia Deaf and Dumb Institute, 

 in addition to much other valuable assistance, has kindly looked over 

 the proofs as they came from the press and suggested many important 

 additions and improvements, for which service my special thanks are 



due. 



L. F. W. 



Washington, December 25. 1881. 



