266 PROCEEDINGS OF SOCIETIES. 
Chlorophyll Bands in the Spectrum.” The subject was illustrated by 
drawings, and the paper will be found printed at p. 225, 
The President, in proposing a vote of thanks to Mr. Palmer, said 
he was very glad to find that others beside himself had taken up the 
question of the spectra of the colouring matters of plants. The 
subject was one which he had worked at for some years, and it had 
proved so extensive that he felt he was only just beginning the in- 
quiry. These colouring matters are much more complex than is 
generally supposed, most of them are undoubtedly mixtures of two or 
three kinds of matters, and even the chlorophyll—the green colouring 
matter alone, is composed generally of two green matters, which exist 
separately in certain plants, and yet these facts had been overlooked 
by all observers excepting Professor Stokes and himself, and certainly 
they had been entirely ignored by all the Continental observers. The 
line it would be most important to carry out would be what were the 
chemical differences which gave rise to these changes in the spectra ? 
This was a line of inquiry which would necessarily take a very long 
time, and would involve an immense amount of work on the part of 
an observer. There was a great deal yet remaining to be done, and 
he was extremely pleased to find that the subject was being now 
taken up. 
The thanks of the meeting were unanimously voted to Mr. Palmer 
for his paper. 
Mr. Palmer said he had noticed a curious effect some time ago 
when examining a red solution of litmus; he found that when very 
bright light was obtained by using an angular prism as the reflector, 
instead of the spectrum going off quite black towards the violet end, 
he could see the line H, through the dark band. 
Mr. Hawkins Johnson inquired whether the absorption bands 
shown by a fluid under the spectroscope indicated any more than the 
difference in the colours of fluids, and whether the instrument was 
capable of distinguishing between colourless solutions, for example, 
between chloride of potassium and carbonate of soda ? 
The President said that though there might be in some cases dif- 
ferences observed between solutions which appeared to have scarcely 
any colour, the spectroscope was not competent to distinguish the 
difference in the chemical qualities of two such solutions as those 
named. He had, however, little doubt that there were many sub- 
stances which appear colourless, which would give definite spectra 
if our eyes enabled us to see farther into the red or the blue ends of 
the spectrum than they are able to do. 
The President said they had a paper that evening by the Abbé 
Rénard, which was of much interest in a geological point of view. 
The Abbé was present, but although he spoke English well, he felt he 
would rather not read the paper himself, though he was quite willing 
to address them in French. That course, however, being unusual, at 
his request Mr. Ingpen had kindly undertaken to read a résumé of the 
paper, the whole of which would be printed in the Journal. 
Mr. Ingpen then read a résumé of a paper by M. ’ Abbé Rénard, 
of Louvain, “ On the Mineralogical Constitution and Microscopical 
Characters of the Whetstones of Belgium.” 
