Changes caused on the Spectrum, &e. By T. Palmer. 235 
On examination it will be found to be not unlike that of red 
Cineraria, though the blue end in this case is absorbed. I now 
added a few drops of acid to the solution, stopping immediately 
that the change of colour took place. This addition has, as will be 
Seen on reference to Fig. 12, had a contrary effect on the first 
two bands; they are, however, increased in definition, though their 
shapes are of Class 2 or unsymmetrical, while in the case of 
Fig. 11 they are of Class 1 or symmetrical, and the general ab- 
sorption in Fig. 12 has advanced towards the red. 
Fig. 12.—Hyprricense Actp. 
M. | Ar. Observations. 
Bsa Riek) Sa 8 . 
l 22°92 | Centres a, see: aay Class 2. Very black, shaded to the 
Peeks iy Bind v2 ai" §La0 |) S6b 5's right, 
mec set | entre: .toeee || 4320 : ‘ 
2 { 90:2 Bates (et noe \ » 2. Black, shaded to the right. 
3 | 20°6 | Commencement | 512:0 | General absorption. 
Through the kindness of Mr. Sorby, whom I now take the 
opportunity of most sincerely thanking, I am enabled to say that 
the first of these two spectra is not the usual one given by the 
colouring matter of normal hypericene. He lent me a tube of 
pure hypericene, the spectrum of which nearly accorded with that 
of my acid form, though the centres of the bands were different. 
My first solution, Fig. 11, we are therefore inclined to think is due 
to the presence of a yellow substance very common in plants, which 
is made deeper by the addition of an alkali, and much paler by an 
acid, in which latter case the intensity of the absorption would be 
increased ; the effect of this is that my solution is yellower than 
Mr. Sorby’s, and would be made more red by acid. Perhaps it 
would interest you to know the coloured oil is not unlike that of 
the solution in water, and like this has no fluorescence. 
This example now closes my remarks. I think I have brought 
suffiaent evidence, if not of proof, to substantiate what I have said, 
at least enough to open up a field for an immense amount of 
research. The conclusion which I draw from these few specimens 
is, that any plant, colouring matter, or substance may be so acid 
that the limit of the band of total absorption may be extended 
beyond one’s vision into the violet, or that the contrary effect ma 
be produced on the red by an alkali in excess. That both these 
states may be present, and that they both may affect the spectrum 
in their own particular way at the same time, is evident. 
