456 
PROFESSORS A. W. REINOLD AND A. W. RUCKER ON 
Column III. the thickness in terms of 10 -5 centims., according to Newton’s scale. 
Column IV. the thickness according to the observations on Newton’s rings. 
Column Y. the thickness according to the corrected scale. 
Column YI. the difference of thickness corresponding to a tenth of a tint in each of 
the colours measured. 
Column YII. the mean quotient for each colour obtained in September and October, 
1879, each (for the reasons given) divided by their mean. 
Column YIII. the mean quotients obtained in September and October, 1880, also 
divided by their mean to make them comparable with the preceding. 
Column IX. the difference between unity and the mean of the numbers in columns 
VII. and YIII., expressed in terms of O’OOl. 
Table II. 
I. 
II. 
111. 
IV. 
V. 
VI. 
VII. 
VIII. 
IX. 
First order — 
Red. 
R (1, 5) 
2-84 
•032 
1-003 
+ 3 
Second order — 
Violet .... 
V (2, 5) 
3-05 
•on 
1-010 
+ 10 
Blue. 
B (2, 5) 
3-34 
3-53 
•081 
1-000 
0-998 
- 1 
Green .... 
G (2, 5) 
3-78 
4-09 
•034 
1-003 
0-999 
+ 1 
Yellow .... 
Y (2, 5) 
4-07 
4-50 
4-54 
•054 
0-998 
1-000 
- 1 
Orange .... 
0 (2, 5) 
4-31 
4-91 
■022 
0-996 
0-995 
- 4 
Red. 
R (2, 5) 
5-22 
■040 
1-006 
1-003 
+ 5 
Third order — 
Purple .... 
P (3, 5) 
5-59 
■035 
0-996 
0-995 
- 4 
Blue. 
B (3, 0) 
5-73 
5-77 
•053 
0-997 
0-993 
- 5 
55 ..... 
B (3, 5) 
Or 
GO 
Zn 
6-03 
Green .... 
G (3, 5) 
6- 29 
6"56 
•053 
P006 
1-000 
+ 3 
Yellow .... 
Y (3, 5) 
6-79 
7-11 
7-10 
"056 
1001 
1-002 
+ 2 
Red. 
R (3, 5) 
7-25 
7-65 
•051 
1-003 
0-994 
- 1 
Bluish-red . 
BR (8, 5) 
8-00 
8-15 
•051 
1-001 
0-997 
- 1 
Fourth order —- 
Green .... 
G (4, 0) 
8-58 
8-41 
•103 
0-997 
1-004 
+ 1 
55 • • 
G (4, 5) 
8-93 
Yellow-green . 
YG (4, 5) 
9'00 
9-71 
9-64 
•041 
1-004 
1-002 
+ 3 
Red. 
R (4, 5) 
10-08 
10-52 
■134 
0-994 
0-997 
- 4 
Fifth order — 
Green .... 
G (5, 0) 
11-29 
11-19 
•141 
0-995 
1-000 
_ 2 
55 .... 
G (5, 5) 
11-50 
11-88 
Red. 
R (5, U) 
12-66 
12-60 
•i.50 
0-996 
0-997 
- 3 
D. 
R (5, 5) 
13-12 
13-35 
Sixth order —- 
Green .... 
G (6, 0) 
14-01 
14-10 
•138 
1-001 
+ 1 
55 .... 
G (6, 5) 
14-68 
14-79 
Red. 
R. (6, 0) 
15-44 
15-48 
•157 
1-009 
+ 9 
' 9. 
R (6, 5) 
16-25 
16-27 
Seventh order— 
Green .... 
G (7, 0) 
16-99 
17-05 
•164 
55 .... 
G (7, 5) 
17-75 
17-87 
Red. 
R (7, 0) 
18-49 
18-69 
•i.35 
55 . 
R (7, 5) 
1925 
19-36 
. . 
Eighth order—- 
Green .... 
G (8, 0) 
20-04 
20-04 
•Ill 
. . 
Red. 
R (8, 0) 
2115 
21-15 
* • 
