$th December, 1882. 



The President, R. L. Patterson, Esq., in the Chair. 



A Paper was read by Mr. John Brown, on 

 THE ATMOSPHERIC FEEDING OF PLANTS. 



The reader referred to the fact that though much care was taken 

 to provide plants with soil which should supply them with the 

 various salts and other matters necessary to their growth, carbon, 

 which forms so large a portion of organic tissues, could not be 

 so supplied, since it is obtained from the air, where it exists in 

 the form of carbon dioxide or carbonic acid gas. On consider- 

 ing the small quantity of this gas present in the air, representing 

 only 1^ part of carbon in 10,000 of air, it had occurred to him 

 that plants must have considerable difficulty in obtainiug 

 sufficient for their wants, and they would probably thrive better 

 and grow faster in air atmosphere richer in carbon dioxide. To 

 test this supposition six young pea plants were planted in pairs 

 in three garden pots, covered with bell glasses, and all under like 

 conditions, except that No. 1 bell glass had a current of carbon 

 dioxide constantly passing into it ; and under No. 3 was placed 

 a dish containing solution of caustic potash, to absorb, if 

 possible, all carbon dioxide in the air within it. No. 2 was left 

 normal for comparison. In four days after the gas had been 

 admitted there was a decided difference between Nos. 1 and 3. 

 A week after this the difference was very striking. No. 1 had 

 vigorous large dark leaves and stems half as thick again as No. 



