OF SOME OF THE CHEMICAL ELEMENTS. 
151 
latter contained several lines which were not in the Wollaston specimen. The lines 
only which were common to both spectra were measured, and are given in the Tables. 
Nebulous bands, probably resolvable, are seen at 1000, and from 1219 to 1233. 
33. Platinum . — The lines of platinum are not easily observed, as several of them are 
fainter than the air lines near which they occur. The points of platinum must be 
brought near each other. The spectrum was mapped from electrodes of platinum wire 
specially prepared by Messrs. Johnson and Matthey as “ pure” platinum. 
There are two bands of fine lines at 913 and 939. 
34. The spectrum of Lithium was observed from electrodes of metallic lithium. Only 
one line of moderate intensity was seen in addition to the three strong lines which are 
known. The numbers are 52T5 6 s, 856 8 s, 20 1 3 2 s, 2732 s n. 
35. Several other spectra have been measured, or are in progress ; these are reserved 
until the remaining metals and elements, as far as may be practicable, have been investi- 
gated. 
Note to the Tables. 
Upon a, re-examination of the Tables I found that it frequently occurred that lines of 
two or more metals were denoted by the same number. It appeared probable that these 
lines having a common number were not coincident, but only approximated in position 
within the limits of one unit of the scale employed ; and besides, there might be small 
errors of observation. I therefore selected about fifty of these groups of lines denoted 
by common numbers, and compared the lines of each group the one with the other, by 
a simultaneous observation of the different metals to which they belong. Some of the 
lines were found to be too faint and ill-defined to admit of being more accurately deter- 
mined in position relatively to each other. 
The following lines appear with my instrument to be coincident. 
Zn, As 909 Na, Ba 1005 O, As 1737 
Na, Pb 1000 Te, N 1366 Cr, N 2336 
Of a much larger number of groups, the lines were, by careful scrutiny, observed to 
differ in position by very small quantities, corresponding for the most part to fractional 
parts of the unit of measurement adopted in the Tables. These are — 
Sn 
459 
Ba 
621-5 
Te 
657 
Bi 
837-3 
Co 
937 
Sb 
1081 
Te 
1485 
Zn 
1797 
Sb 
458-8 
Bi 
621 
Cd 
656 
Sb 
837 
Sb 
937-5 
An 
1081-5 
Fe 
1485-3 
Pd 
1798 
Ca 
515 
Ca 
622 
Fe 
696-2 
Cd 
889 
Au 
981 
Ca 
1256 
T1 
1505 
T1 
1851 
An 
516 
Fe 
623 
Zn 
696 
Sb 
889-5 
Sb 
981-5 
Co 
1257 
Mn 
1505-5 
Bi 
1851-3 
Te 
545-5 
An 
643 
Sb 
765 
As 
908-8 
Ca 
1031 
Fe 
1276 
Pd 
1548 
Sb 
1900 
Sb 
545 
Ca 
642 
Te 
765-3 
Mn 909 
Pd 
1031-5 
Ag 
1276-3 
Fe 
1548-2 
Pb 
1900-3 
Fe 
641-5 
Ag 
1031-2 
N 
1900 
Pb 
1031-1 
Sn 
581 
Ca 
649 
Na 
818-3 
Ca 
921-2 
Te 
1030-3 
Fe 
1438 
Pb 
1593-3 
Bi 
581-5 
Sn 
648 
Ca 
818 
T1 
921 
Te 
1438-3 
Fe 
1593 
Co 921 
Sb 921-1 
