126 Harriey—An Investigation of the Connexion between 
10 portions shows five bands—four being stronger than the foregoing. Similarly, 
0:01 gr. in 1 portion has two feeble bands, but the same quantity in 10 portions 
has three, that between A 4650 and 4279 being a strong band. This confirms the 
previous observations. The sharp composite bands result from the vibrations 
within the molecules. 
LEAD. 
The salt used was lead acetate dissolved in water. Pb (CH;: COO), : 2H,0. 
Quantity of Description of Spectrum. 
Lead. 
(1) 0°5 gr. in The characteristic strong banded spectrum of lead. The 
1 portion. bands which are degraded towards the red are fluted bands, 
extending the whole length of the spectrum, but they are 
strongest between 4900 and 4058. They are simple bands, 
that is to say, not composed of groups of lines. Lines ) 4058, 
3682, 3639, all strong. The two silver lines \ 3388 and 3281 
are also faintly visible, and are impurity lines. 
(2) 0-1 gr. Bands. Strong between \ 4900 and 4058. Lines. The three 
lead lines are all strong. 7 
(3) 0°01 gr. Bands. Between \ 4900 and 4058 are feeble. 
(4) 0:001 gr. No bands. Lines—The three lines are very feeble. 
(5) 0:0001 gr. The line \ 4058 is just visible. 
(6) 0:00001 gr. Nothing visible. 
(1) 0-1 gr. in Bands. Between d 4900 and 4058 are strong. Lines. The 
1 portion. three ) 4058, 8682, 3639 are strong. 
(2) O-1 gr. in The spectrum is almost identical with the above, the diffe- 
10 portions. rence being that the bands are somewhat more diffuse. 
(3) 0:01 gr. in No bands. The three lines are fairly strong. 
1 portion. 
(4) 0:01 gr. in No bands, but a feeble continuous spectrum is visible between 
10 portions. 4900 and 4058, where the bands are strongest in the foregoing 
| spectra. The three lead lines appear strong. 
(5) 0-001 gr. The bands are extinct and the three lines feeble. 
In spectrum (4), the feeble continuous rays visible between 14900 and 4058 
are in all probability caused by the burning of the filter-papers, and if so are the 
spectrum of carbon monoxide. 
