THE MICROSCOPE. 175 
to which he is really entitled. Both of these circumstances have 
affected his reputation abroad somewhat unfavorably. 
The first is the very large claims in regard to his work, put forth 
for Mr. Fasoldt by some of his friends, and, to a certain extent, it 
must be admitted, by Mr. Fasoldt himself. The second is a rugged 
and somewhat unusual style in his public communications. The 
latter must be charged wholly to the fact of his inability to convert 
into felicitous English an essentially German style of speech. 
Mr. Fasoldt was a mechanician of rare skill, and he had that 
element of character which is almost always found associated with 
real genius—supreme confidence in his own work. This striking 
trait of his character was of real advantage to him since it led him to 
answer criticism by doing better work in new ways. The improve- 
ment in his micrometers is especially noticeable. At one time he 
claimed that his micrometers had no measurable errors. This was 
simply an expression of faith in his own work at that time. With 
more experience he found that he had been too sanguine, and so he 
set for himself the problem of finding the best way to overcome 
these errors. It will be admitted by all who have used his microme- 
ters, especially those made within the last five years, that his success 
in this direction has been remarkable. The fact that Mr. Fasoldt, at 
one time, thought he had reached a degree of perfection greater than 
is in reality possible, ought not to be remembered against him. He 
is not the only person who has had, at different times, too great a 
degree of confidence in his own work, as the writer can testify from 
personal experience. 
Mr. Fasoldt maintained great secrecy in regard to his methods 
ofruling. The writer believes that the secret of his success consisted 
wholly in his skill in the preparation of his ruling diamonds. There 
is some evidence, derived from measurements of his rulings, that he 
did not use a screw. According to my own experience, there is no 
difficulty whatever in making the mechanical subdivisions of the ruled 
spaces far beyond the ability of the ruling diamond to cut a clean 
line which has a width less than the interlinear space. But whatever 
method Mr. Fasoldt may have employed, the results which he 
obtained must always command the admiration of microscopists, and 
the service which he has rendered in micrometry deserves grateful 
recognition. 
Waterview, Mez., May 19. 
FRAENKEL AND Pretrrer, of Berlin, are publishing an atlas of 
bacteriology, in parts. 
