572 ANNUAL EECORD OF SCIENCE AND INDUSTRY. 



of its pollen with him, is impregnation probable. Tmnen^ 

 Jour, Bot.^ Aprils 1873, 101. 



INFLUENCE OF ATMOSPHERIC PEESSURE ON THE GROWTH OF 



PLANTS. 



The important researches of Bert upon the effect of varia- 

 tions of atmospheric pressure on the phenomena of animal 

 life have lately been extended by him to the consideration 

 of plants, especially in reference to the germination of barley 

 and wheat, which contain albumen, and of cress and turnips, 

 which do not. He finds that, on diminishing the pressure, 

 the germination is proportionally slower, and that it stops at 

 lengths between one and a half and four inches, the seeds not 

 dying, but only becoming inactive. He attributes this to a 

 stoppage of the oxidation necessary to development of the 

 embryo, because of the feeble tension of oxygen. 



With increase of pressure to two or three atmospheres, 

 the seeds appear to profit somewhat, but above one and a 

 half to two inches there is evident disadvantage, especially 

 for seeds with farinaceous albumen. At very high pressures 

 the seed is killed ; it is also killed when submitted to com- 

 pression after development has commenced. The too great 

 tension diminishes the oxidation ; and on examination of the 

 compressed air in which seeds have been sown, it is found 

 that the consumption of oxygen has been much less than at 

 normal pressure. These results have an important bearing 

 on the geographical distribution of plants a subject which 

 M. Bert hopes to treat of on some future occasion. 18 A^ 

 July 4, 1873, 401. 



THE INFLUENCE OF ELECTRICITY ON THE GROWTH OF PLANTS. 



M. H. Bridgman, of Norwich, England, has lately investi- 

 gated the influence of electricity on the growth of plants, and 

 has used for this purpose a very weak galvanic battery, or 

 rather a single element with weak acids, in order to obtain a 

 very weak current. He takes a three-inch square glass plate, 

 and after laying upon it two strips of sheet tin close to but not 

 touching each other, covers the plate with felt soaked in rain 

 water. On the latter he spreads a thin layer of cress seeds, 

 that have previously been well soaked in rain water. The 

 two wires of the battery are then brought into contact with 



