PREFACE. Vi 
possibly to supplement both by a more advanced work on each 
subject separately. However this may be, it is quite certain 
that the measure of our progress in any science may be found in 
our ability to adapt the thought and experience of other nations 
to our special needs and resources. 
The plates used are taken mostly from the text-books of 
J. Wiesner and Th. Hartig to both of whom the author hereby 
expresses most hearty thanks, as well as to the numerous friends 
who have aided and assisted in the preparation of the work. 
EMILY L. GREGORY. 
New York, June, 1895. 
