Le einen 
A 
Account of a Compound Achromatic Microscope. 239 
see them only with great difficulty. I do not think Spencer’s 
microscope quite equal to the far more expensive English ones 
made by Ross or Powell, and I cannot positively assert that it is 
superior to the best of those made by Oberhauser or Plassels, as 
I have not had an opportunity to compare them properly side by 
side in the same light ; my impressions however are that the mi- 
croscope made by Mr. Spencer for Dr. Gilman, is in no respect 
inferior to any of Oberhauser’s that I have seen, and I am by no 
means certain that it is not superior. I certainly had a better 
Copy of the Report on Mr. Charles A. Spencer's Microscope, made to the Lyceum of 
Natural History. 
Your committee have been able to subject the microscope made 
by Mr. Charles A. Spencer, to this rigorous comparison with an in- 
