6-4 Royal Society : — 



good while engaged at intervals with an optico-chemical examination 

 of chlorophyll. I find the chlorophyll of land-plants to be a mix- 

 ture of four substances, two green and two yellow, all possessing 

 highly distinctive optical properties. The green substances yield 

 solutions exhibiting a strong red fluorescence; the yellow substances 

 do not. The four substances are soluble in the same solvents, and 

 three of them are extremely easily decomposed by acids or even acid 

 salts, such as binoxalate of potash ; but by proper treatment each 

 may be obtained in a state of very approximate isolation, so far at 

 least as coloured substances are concerned. The phyllocyanine of 

 Fremy* is mainly the product of decomposition by acids of one of 

 the green bodies, and is naturally a substance of a nearly neutral 

 tint, showing however extremely sharp bands of absorption in its 

 neutral solutions, but dissolves in certain acids and acid solutions 

 with a green or blue colour. Fremy*s phylloxanthine differs accord- 

 ing to the mode of preparation. When prepared by removing the 

 green bodies by hydrate of alumina and a little water, it is mainly 

 one of the yellow bodies ; but when prepared by hydrochloric acid 

 and ether, it is mainly a mixture of the same yellow body (partly, 

 it may be, decomposed) with the product of decomposition by acids of 

 the second green body. As the mode of preparation of phylloxan- 

 theine is rather hinted at than described, I can only conjecture 

 what the substance is ; but I suppose it to be a mixture of the second 

 yellow substance with the products of decomposition of the other 

 three bodies. Green seaweeds (Chlorospermece) agree with land- 

 plants, except as to the relative proportion of the substances pre- 

 sent ; but in olive-coloured sea-weeds (JMelanospermece) the second 

 green substance is replaced by a third green substance, and the first 

 yellow substance by a third yellow substance, to the presence of 

 which the dull colour of those plants is due. The red colouring- 

 matter of the red sea-weeds (Rhodospermeoe), which the plants con- 

 tain in addition to chlorophyll, is altogether different in its nature 

 from chlorophyll, as is already known, and would appear to be an albu- 

 minous substance. I hope, before long, to present to the Royal 

 Society the details of these researches. 



March 3. — Major- General Sabine, President, in the Chair. 



The following communication was read : — 



" On the Spectra of Ignited Gases and Vapours, with especial 

 regard to the different Spectra of the same elementary gaseous sub- 

 stance." By Dr. Julius Pliicker, of Bonn, For. Memb. U.S., and 

 Dr. S. W. Hittorf, of Munster. 



In order to obtain the spectra of the elementary bodies, we may 

 employ either flame or the electric current. The former is the more 

 easily managed, but its temperature is for the most part too low to 

 volatilize the body to be examined, or, if it be volatilized or already in 

 the state of gas, to exhibit its characteristic lines. In most cases it 

 is only the electric current that is fitted to produce these lines ; and 



* Comptes Rendus, torn. 1. p. 405. 



