352 Proceedings of the British Association. 



sion its decomposition. The moment the oxygen is withdrawn 

 from its state of combination, it has two affinities to choose be- 

 tween, and the attraction of the oxalic acid being greater, it 

 passes over to it, converting it into carbonic acid. The protoxide 

 of manganese still remaining, will act on fresh portions ad infini- 

 tum. Most of the vegetable acids may be decomposed in a sim- 

 ilar manner. 



Mr. R. Hunt communicated a paper entitled " Researches on 

 the Influence of Light on the Germination of Seeds and the 

 growth of Plants. The subject had been intrusted to Mr. Hunt 

 for experiment. He had provided six boxes, so constructed, that 

 no light could enter except through glass, of different colors, — 

 the first being deep red, the last deep green. In these boxes 

 he had raised ranunculi, tulips, and other plants. The tulips he 

 found germinated, the first under the orange-glasses, and last un- 

 der the blue and green. Under the blue glass, the plants, al- 

 though slower in germination, were more healthy, and promised 

 to come to maturity, and be perfect flowers: while under the 

 orange they were more forward but sickly. A curious result was 

 noticed with respect to the red glass. Under all other circum- 

 stances, plants bent, towards the light, but those under the red 

 glass bent away from the light. In nearly all cases germination 

 had been prevented by the absorptive power of the yellow rays. 



On the agricultural importance of ascertaining the minute por- 

 tions of matter derived from organic sources that may be preserv- 

 ed in the surface soil, and on the chemical means by ivhich its 

 presence may be detected; by Dr. Daubeny. — The researches of 

 Sprengel and Liebig, by showing the manner in which minute 

 quantities of certain ingredients may impart to the soil into which 

 they enter as constituents, entirely new properties with reference 

 to the purposes of agriculture, have given additional interest to 

 the methods of analysis, which aim at determining the chemical 

 composition of the surface, and of the substratum from which 

 the former principally derives its chief ingredients. The rude 

 mechanical method adopted, even by such chemists as Sir H. 

 Davy, is no longer considered sufficient. The nature, as well as 

 the amount of the organic matter present, and the existence of 

 phosphates, &c. in the proportion of one thousandth or even one 

 ten thousandth part of the entire mass, are points deserving in- 

 vestigation, and afford a clue to the description of manures most 



