PREFACE. XXI 



The colored plates illustrating the report were either drawn by the 

 writer or by Miss Lillie Sulliv^au under his immediate direction. Plate 

 ly is reproduced from Glover's copper-plate etchings j Plates VI to XI 

 were drawn by Messrs. Burgess and Minot from material furnished for 

 the purpose ; Plates XIV to LXI were either adapted from patent draw- 

 ings or photographs, or were drawn by Dr. Barnard or by us either 

 from the original machinery or from photographs thereof; Plate LXII 

 is made up from drawings of our own, and Plates LXIII and LXIV 

 were drawn by Dr. George Marx. 



C. V. E. 



