160 
ON THE SPECTRA OF SOME OF THE CHEMICAL ELEMENTS. 
Note to Plates I. and II. 
spectra have been laid down limits the intensity that can 
to the stronger lines. From this cause the spectra, as 
If greater force had been given to the lines, by making 
them broader, they would, in several spectra, have occupied singly the space in which 
two or more lines have to be laid down. This deficiency in strength of some of the 
lines is more appreciated by the eye, in consequence of the shortness of the lines of the 
spectra, with the exception of those of the air-spectrum. The narrowness of the spectra 
of the metals is unavoidable, if the great advantage of having all the spectra upon one 
Plate is retained. 
In some of the spectra bands of unresolved light occur ; these, in the Plates, are crossed 
with lines that they may be distinguished from groups of fine lines. 
The scale upon which the 
be given, in the engraving, 
engraved, appear too faint. 
