238 Account of a Compound Achromatic Microscope. 
in these respects is vouched for by Prof. Bailey, and by the 
Report presented to the New York Lyceum of Natural History, 
by Prof. Torrey, Dr. Le Conte, and Mr. Holton. 
It is only because I have been in the daily habit of using the 
microscope, and by such use have become familiar with its pow- 
ers, that I venture to add my own opinion, that the glass is for 
ordinary use in scientific investigations, as superior to the instru- 
ments of Chevalier, Plassels, and Oberhauser, as it has been 
proved to be when applied to difficult tests. It is both more 
pleasant and more satisfactory as a working microscope, than any 
I have seen. 
It is with no ordinary satisfaction, that I introduce to the sci- 
entific men of the United States, a countryman of our own, who 
has in the very outset of his career, achieved so great a triumph 
in practical optics as the construction of a compound achromatic 
microscope, which compares most favorably with those made by 
the first artists in Europe. To him we may look for future dis- 
plays of scientific skill, which shall make us entirely independent 
of the old world in this important respect. 
The friends of American industry and talent will be pleased to 
hear, that Mr. Spencer has already received orders for microscopes 
from public institutions and private individuals. Professor Henry 
has ordered an instrument of high power for the Smithsonian In- 
stitute. American patronage, we may hope, will not be wanting 
to American art. 
The testimonial of Prof. Bailey, and the Report alluded to above, 
are here subjoined. 
FROM PROFESSOR BAILEY. 
West Point, N. Y., Nov. 27, 1847. 
and which ‘was sent to me from England, as the test object par 
,) while with Chevalier’s, by the same light, I could 
