REVIEWS. 425 
jectives have accomplished some things which the American have hith- 
erto failed to do.” It is not the purpose of this paper to produce evidence 
outside of Dr. Hagen’s own statements, as to what American objectives 
have done. It is only needful to contrast what he says above with what 
he says he himself saw. Dr. H. says ‘‘that an objective 1-10th inch with 
ocular C. showed while band 19 [of the Nobert test plate] was in the cen- 
tre of the field, the 18th, 17th, and half of the 16th bands; the lines in all 
were well defined, but not so that I could have counted them all. I could 
seen at once? If either of these suggestions are answ in the nega- 
tiv H has himself seen the 19th band resolved with a 
olles’ objective. But agen says that American objectives have 
objective, is much ** more" than to see all the lines with a 1-16 (really 
a 1-20). He never saw, read of, or heard of a 1-10 European objective 
