ON THE MEASUREMENTS OF WAVE-LENGTHS. 
7 3 
Table of means and numbers adopted as correct measurements of the fiducial lines 
on each plate. 
Spectra to the left. 
Portions 6-12. Measurements in hundredths of an inch. 
( 1 ) 
Fiducial lines. 
Mean 
measurements. 
Adopted numbers. 
Intervals. 
I. 
0-03 
0-15 
37-05 
II. 
37-25 
37-20 
37-10 
III. 
74-30 
74-30 
37-20 
IV. 
111-575 
111-50 
37-30 
V. 
148-815 
148-80 
37-40 
VI. 
186-21 
186-20 
37-50 
VII. 
223-685 
223-70 
37-65 
VIII. 
261-35 
261-35 
37-80 
IX. 
299-145 
299-15 
38-00 
X. 
337-255 
337T5 
( 2 ) 
Fiducial lines. 
Mean 
measurements. 
Adopted numbers. 
Intervals. 
I. 
II. 
37-25 
37-25 
37T5 
III. 
74-50 
74’40 
37-25 
IV. 
111-70 
111-65 
37-35 
V. 
149-05 
149-00 
37-45 
VI. 
186-45 
186-45 
37-55 
VII. 
223-985 
224-00 
37-70 
VIII. 
261-68 
261-70 
37-85 
IX. 
299-575 
299-55 
38-05 
X. 
337-59 
337-60 
i 
MDCCCLXXXIV. L 
