66 Capt. Kater’s experiments for determining the 
Hence the distance between the knife edges is 39,4 inches 
-f-956,47 divisions of the micrometer. 
June 12th, the knife edges having been adjusted parallel to 
each other, the following measurements were taken, the knife 
edges being viewed as dark objects on a white ground. 
Dark on a 
white ground. 
Readings of the micrometer. 
Date. 
Near side of 
the bar. 
Further side 
of the bar. 
Mean. 
Scale. 
Divisions 
+ 39,4 in. 
June 
50,0 
50=0 
50=00 
1006,5 
95 6 = 5 o 
12 
50,0 
50,0 
50, OO 
— 
956,50 
50,0 
50,0 
50,00 
— 
956,50 ] 
49,° 
50,0 
49,5° 
— 
956,50 | 
12 
4 6 5 
44,° 
42,25 
1001,0 
955,75 
\ 44 >5 
44,5 
45,50 
1001,0 
955,50 
42,0 
43>° 
42,5° 
1003,0 
960,50 
43>° 
43 >° 
43,00 
ioo3„o 
960,00 
*3 
37=5 
38,0 
37=75 
994,0 
956,25 
35 =o 
39P 
37 =oo 
993=5 
956,50 
38,0 
35=o 
36,50 
1001,0 
964=50 
38,0 
38,0 
38,00 
— 
963,00 
H 
*5=5 
2 7,5 
26,50 
987,0 
960,50 
2 5=0 
2 6,5 
2 5=75 
987,5 
96i,75 
24,0 
25,2 
24,60 
— 
962,90 
25, 0 
25,7 
25,25 
■ — 
962,25 
14 
79=5 
78,0 
78,75 
1042,0 
963,25 
76,0 
75=o 
75 >5° 
— 
966,50 
72,0 
7 l =5 
7i,75 
1035,2 
9 6 3,45 
74>° 
73=5 
73,75 
■ — 
961,45 
Mean of the whole 
Correction for irradiation 
(see page .59) 
960,00 
—5,51 
1 
954,49 
