102 Mr Horner o7i the Quantity of Solid Matter 



It is thus that matter-of-fact observations sometimes lead to- 

 wards points of the very deepest importance. 



I shall add, that repeated researches upon fossil vegetables, 

 may possibly indicate eventually, the positions of the poles 

 and the equator of each geological epoch. It would for this 

 suffice to discover in which direction the number of the species 

 which require the most heat and the most uniform light, increases 

 or diminishes. 



M. Brongniart, in the remaining part of his work, enters 

 argely into detail concerning the action of light on plants. A 

 knowledge of the first elements of botanical j)hysiology, is suffi- 

 cient to shew that this agent determines the evaporation and the 

 respiration of plants by their leaves — fimctions whence result 

 the green colour, the fixation of carbon in the plants, the direc- 

 tion of the branches, &c. The intensity and the regularity of 

 the solar influence are in the highest degree important to vege- 

 tables. 



So much, then, we now supply, to demonstrate the interest 

 which is connected with researches regarding fossil vegetables ; 

 and the gratitude we owe to the distinguished naturalists, who, 

 during forty years, have prosecuted this branch of study with 

 unlooked-for success. — Bibl. Universclle, July 1834. 



On the Quantity of Solid Matter suspended in the Water of the 

 Rhine. By Leonard Hokneu, Esq. F.R.S.L. and E., and 

 F.G.S. (Communicated by the Author.)* 



The attention of geologists has been more particularly di- 

 rected of late to the importance of ascertaining the quantity of 

 solid matter held in suspension in the water of different rivers, 

 as affording a measure of the amount of abraded stone trans- 

 ported to the sea, there to constitute the materials of new strata, 

 now in progress of formation. 



During a late residence at Bonn, I began a series of experi- 

 ments on the quantity of solid matter suspended in the water of 

 the Rhine, in that part of its course. Several interruptions 



• Read before the Geological Society 2Gtli February 1834. 



