PREFACE. 
XXI 
The colored plates illustrating the report were either drawn by the 
writer or by Miss Lillie Sullivan under his immediate direction. Plate 
IV is reproduced from Glover's copper-plate etchings ; 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 bv Dr. George Marx. 
C. V. R. 
