REGISTRATION OF THE CHEMICAL ACTION OF TOTAL DAYLIGHT. 
G13 
Intensity of Fixed Tints. 
Fixed Tint. 
Expt. 1. 
Expt. 2. 
Expt. 3. 
Expt. 4. 
Expt. 5. 
Expt. 6. 
Expt. 7. 
Expt. 8. 
Expt. 9. 
Expt. 10.! 
Expt. 11. 
Expt. 12. 
I. 
2-336 
2185 
2067 
1-768 
n. 
1-767 
1-709 
1-647 
1-585 
1-689 
1-524 
1-548 
hi. 
1-480 
1-328 
1-356 
1-346 
1-276 
1-182 
1-289 
1-235 
1-317 
IV. 
V. 
0-840 
0-698 
0-891 
0-515 
0-838 
0-544 
0-794 
0-473 
0-773 
0-755 
Mean Intensity. 
Fixed Tint No. 1 2-089 Fixed Tint No. IV 0-798 
„ II 1-637 „ V 0-512 
„ III 1-312 
(2) Graduation of fixed strips B and C, by means of the fixed tints. The graduation of 
the fixed strips by means of the fixed tints is now made in the way described in the 
first method. 
Headings on 
fixed strip B. 
Headings on 
fixed strip C. 
Corresponding 
intensity. 
millims. 
millims. 
millims. 
Fixed tint I. 
20-2 
27*7 
2-089 
„ II 
3-88 
42-8 
1-637 
„ III 
67-3 
71-7 
1-312 
„ IV 
105-1 
100-6 
0-798 
„ V 
129-0 
122-6 
0-512 
Standard tint 
96-0 
97-5 
1-000 
The Intensity Tables for these two strips are obtained by careful graphical interpola- 
tion from the above numbers ; the curves are given (in black) on Plate XXVIII. fig. 2, 
the abscissae representing the position on the millimetre-scale of the strips, and the 
ordinates the corresponding intensities. In every case the normal tint (intensity =1-00) 
is read off on the fixed strip, serving as a control of the accuracy of the graduation. 
A second series of intensity determinations of the same fixed tints with pendulum 
strips is appended for the purpose of controlling the accuracy of the first series. The 
intensities of the fixed tints thus obtained are given in the 3rd column of the following 
Table. A new fixed tint, No. III. A, was introduced of a shade between Nos. III. and 
IV. This new tint was found to coincide with the positions 82-1 millims. and 82-3 
millims. on the strips B and C respectively. The readings of the remaining tints are the 
same as in the first series. 
(3) Second graduation of Strips B and C. 
I. 
II. 
m. 
Headings on 
strip B. 
Headings on 
strip C. 
Corresponding 
intensity. 
Fixed tint I 
20-2 
27-7 
1-935 
„ II 
38-8 
42-8 
1-597 
„ III 
67-3 
71-7 
1-291 
„ III A.... 
82-1 
82-3 
1-123 
„ IV 
105-1 
100-6 
0-807 
„ V 
129-0 
122-6 
0-547 
Standard tint 
96-0 
97-5 
1-000 
4 p 
MDCCCLXV. 
