ASTRONOMICAL OBSERVATORIES. 277 



field of view. The thread which fits the tangent screw is 

 cut in the edge of the ring, detached from the hour circle, 

 and pressed against it by the elasticity of a thin brass 

 plate, which is secured by screws so as to give the re- 

 quisite friction. This arrangement permits the telescope 

 to be moved in any direction, even while connected with 

 the clock, and obviates the necessity of clamping and un- 

 clamping. 



The solar eclipse of May 26, 1854, was carefully ob- 

 served by this telescope, and a series of daguerreotypes 

 (28 in number) were taken at intervals of about five 

 minutes, showing the progress of the eclipse in a novel 

 and beautiful manner. These images, which are two 

 inches in diameter, are extremely well defined, and serve 

 as permanent registers of the transient phenomena of the 

 eclipse. 



OBSERVATORY OF MICHIGAN UNIVERSITY. 



Soon after the Rev. Dr. Tappan was elected Chancellor 

 of Michigan University, in 1852, he conceived the idea 

 of establishing an astronomical observatory in connection 

 with the university. During the succeeding winter the 

 claims of this object were laid before the citizens of De- 

 troit, and they responded to the appeal in a prompt and 

 liberal manner. The sum of ten thousand dollars was 

 almost immediately pledged for this object, and an ad- 

 ditional sum was promised if it should be found necessary. 



The foundations of the building were laid in the sum- 

 mer of 1853, and the observatory was completed in the 



