The Microscope. 

 TABLE OF OBSERVATIONS. 



75 



1. Room not very well lighted. 2. Corrected by glasses. 3. This is clearly an error, 

 though it was so reported. 



Referring to the preceding table it will be noticed that in 16 

 out of 19 observations of No. 1 and No. 2, No. 1 was visible at 

 a greater distance than No. 2 ; and in three cases No. 2 was visi- 

 ble at a greater distance than No. 1. It will also be noticed with 

 reference to No. 1 and No. 2 that in nine cases out of eighteen 

 observations No. 1 was defined at a greater distance than No. 2 ; 

 in eight cases No. 2 was defined at a greater distance than No.l, 

 and in one case they were defined at the same distance. The 

 mean distance, 26 feet and 4 inches at which No. 1 was visible, 

 corresponds to a visual angle of 26.1 seconds of arc, while the 

 mean distance, 22 feet and 11 inches at which No. 2 was visible, 

 corresponds to 30.0 seconds of arc. The mean distance, 5 feet 

 and 10 inches at which No. 1 was defined, corresponds to 57'' 

 of arc ; while the mean distance, 5 feet and 7 inches at which 

 No. 2 was defined corresponds to 2'-3".l of arc. The mean dis- 

 tance, 75 feet at which No. 3 was visible, corresponds to 9".2 of 

 arc. 



