a floating collimator. 
159 
Experiments with the Iron Float. 
4th Set. 
Divisions 
of 
Microtn. 
Difference 
Em)r in Sec*, 
affecting the 
Horiz. point. 
Dec. 10 
Out and replaced, S first - - - 
Ditto, and agitated the mercury, S first 
Ditto - - - ditto 
Ditto - - - ditto 
Ditto - - - ditto 
Ditto - - - ditto 
84>5 
90.3 
89,8 
88,7 
87*3 
84^9 
+ 5 *^ 
— 0,5 
— 1,1 
— 1,4 
— 2,4 
n 
+ 1.74 
— 0,15 
— 0,33 
— 0,42 
— 0,72 
5 th Set. 
Out and agitated mercury, O first 
Ditto - - ditto 
Ditto - - ditto 
Ditto - - ditto 
Ditto - ' - ditto 
Ditto - - ditto 
An acccident suspected 
84.3 
83>9 
82,9 
83,2 
85,0 
79*2 
— 0,4 
— 1,0 
+ 0-3 
+ ij8 
-5*8 
n 
— 0,12 
— 0,30 
+ 0,09 
+ 0*54 
— **74 
The surface of the mercury being very dirty, it was care- 
fully strained through a paper funnel. 
6 th Set. 
Out and replaced S first 
Ditto - - ditto 
Ditto - - ditto 
Ditto - - ditto 
Ditto - - ditto 
Ditto - - ditto 
81.0 
80.9 
78.9 
78,5 
78.0 
77*0 
— 0,1 
— 2,0 
— 0,4 
— 0,5 
— 1,0 
— 0,03 
— 0,60 
— 0,12 
— 0,15 
— 0,30 
The mercury carefully strained through a paper funnel, 
and the support oiled and rubbed dry. 
