SCIENTIFIC COMMITTEE, JULY 13. 



cxiii 



A. Church, having given consideration to the first of the two 

 papers, reserving the second for a future meeting, remarked that 

 Mr. Smee had scarcely paid sufficient attention to the more 

 recent analyses of the atmosphere and of rain ; the amount of 

 CO 2 in the free air over land and sea being now found to be 

 almost absolutely uniform everywhere (except where locally 

 contaminated), and less in quantity than 3 parts in 10,000, so 

 that no conclusions could be drawn from the data furnished in 

 the paper on this point. With regard to the amount of 

 ammonia in the air, it is so infinitesimally small in quantity 

 that it can only be estimated by the most modern and refined 

 chemical operations, so that he was obliged to express some 

 hesitation in accepting Mr. Smee's statements on this point. 

 With regard to Mr. Smee's analysis of pseudo-bulbs and of 

 flowers, Prof. Church observed that they agreed fairly well with 

 the average results hitherto obtained from terrestrial and 

 epiphytic plants, but he thought that the percentage of undeter- 

 mined ash constituents — viz. about one-half, was far too great, 

 and he questioned the presence of aluminium, observing that 

 though terrestrial species of Lycopodium contain much of this 

 metal, epiphytal species of the same genus contain none. He 

 felt sure that some ingredient was wanting which had not been 

 determined. With regard to floral colouring matters, Mr. Smee 

 did not appear to have consulted recent researches. Professor 

 Church had proved that a number of reds, blues, and purples, 

 though called by different names — e.g. colein in the Coleus, 

 erythrophyll in Copper Beech, fruits, &c, cenolinin black grapes and 

 anthocyanin — were absolutely the same thing, being represented 

 by the formula C 20 H 20 O 10 . These became purplish in neutral 

 cells, blue in alkaline, and red in acid cells. Even the blue- 

 green of a certain Ixia was due to an alkaline solution of the same 

 substance. With regard to the beetroot, however, and plants 

 allied to it, as the Amaranthus and Buckwheat, he found that the 

 red-purple was of a different nature, and he had called it 

 " amaranthin." It gave neither a scarlet nor a blue reaction, 

 neither green nor yellow with acids, but Prof. Church had as yet 

 not determined its actual chemical composition, although he 

 had found it to differ from anthocyanin by its insolubility in 

 absolute alcohol, and by the absence from its spectrum of 

 definite absorption bands. With regard to nutritive solutions, 



