<m the Germination of Plants. S15 



ExpER.V.— A sponge was fixed into the mouth of an ale-glass, 

 and its surface cut smooth on a level with the brim. Some mus- 

 tard seeds previously well soaked, were pushed a little way in- 

 to the surface of the sponge, in order to retain their whole sur- 

 faces moist. This apparatus was then tied up in the garden, 

 with the mouth of the glass downwards, and moistened daily. 

 In four days twelve had germinated, and three had grown re^ 

 gvlarly upwards into the sponge. None grew downwards^ but 

 all had endeavoured, more or less, to avail themselves of the 

 moisture of the sponge, by running along its under surface. 

 Soon after this, they became unhealthy. 



ExPEE. VI — Into a thin 

 slip of wood, a a was fixed 

 an upright, h b, having a 

 notch at its upper end, in 

 which was fixed the slend- 

 er wooden beam i c, turning ^ 

 on a fine needle. The 

 apparatus so constructed, 

 was then fixed in the bot- 

 tom of a jar, ^ ^ ^ ^. A 

 bean Ze, the radicle of which 

 projected horizontally from 

 the cotyledons, was fixed by a pin to the lower piece of wood, 

 a a. A thread passed through the apex of the radicle, con- 

 nected it with the beam, the other extremity of which was 

 counterpoised by a ten grain weight, w. Lastly, water was 

 poured into the jar, sufficient to cover the bean. By means 

 of a very simple contrivance, I could detect the slightest de- 

 pression of the beam ; and in two days this was obvious at the 

 extremity i, to the amount of about one-tenth of an inch. 



The same experiment was repeated on a bean, 

 whose radicle was directed upwards, and the 

 light being partially excluded. In two days this 

 likewise most obviously curved downwards, 

 at the same time, for an obvious reason, the 

 beam became raised. The annexed sketch re- 

 presents its appearance, at the close of the ex- 

 periment. 



