512 JUNCTION OP THE FRESH WATER OF RIVERS 



which it counterbalances ; and this, independent of the pro- 

 gressive motion of the tide in the river. 



If the view which we have taken of this subject, in reference 

 to the progress of the salt water, be considered as just, it will 

 enable us to explain some of the phenomena of nature, at pre- 

 sent rather perplexing, and may even be useful in its practical 

 application. 



In examining the vegetable productions of the banks of ri- 

 vers, at their junction with the sea, we are sometimes surpri- 

 ed to witness the growth of plants, considered as the natural 

 inhabitants of the sea-shore. But our surprise will cease when 

 we reflect, that the sea-water proceeds farther up the river at 

 every flood-tide than the sensible qualities of the water at the 

 surface indicate ; so that the plants, which we hastily conclude 

 to be out of the reach of the salt-water, are still within the 

 sphere of its influence. Thus, at the Beach of Flisk, and even 

 farther up the river, the Fucus vesiculosus] (the species common- 

 ly cut for making kelp) not only vegetates, but in its season 

 appears in fructification. 



But that which proves in a still more decisive manner, the 

 action of the inferior stratum of salt-water at the place, is the 

 growth of the coralline termed Tubularia ramosa (Ellis's Co- 

 rallines, Tab. xv. fig. A.), and another of a different genus, 

 closely resembling the Sertularia gelatinosa of Pallas. There 

 are likewise some traces of Flustrce. 



A knowledge of the facts which we have already stated, may 

 be of use to those who are engaged in the erection of salt- 

 works at the mouths of rivers. In such situations, the open- 

 ings of the pipes for obtaining the salt water, should be placed 

 as near the bottom, or as deep in the water as possible ; and 

 water ought only to be drawn during the height of flood-tide, 

 when the fresh-water is diffused over the surface. 



Even 



