On the general Causes of the Ocean-Currents. 23 



A glance at this table shows, that an under-curi-ent of salt water 

 from the Kattegat enters into Elfsborgsfjord towards the mouth of the 

 river, where the salter water rises higher and nearer to the surface the 

 more the stream approaches the embouchure of the river, so that for a 

 certain depth the saltness appears to increase in the direction towards 

 the latter. Wee see also that this under-current penetrates into the bed 

 of the river itself, where its saltness at a given level now no longer in- 

 creases, but neither does it decrease in any sensible degree in the lowest 

 strata. While the under-current thus proceeds at the bottom of the river, 

 it is constantly reduced in thickness; indeed its thickness at the inner- 

 most point, at which I could distinctly observe it, was less than two 

 foot, as may be seen from the following special series, taken on the 

 7*" August. 18500 f above the mouth: 



Depth. Saltness, 7"* August. The existence of the under-current 



0.23 was made directly visible by means 



6 feet 0.3.0 ' of a sunken bodj^, which was moved 



8 » 0.40 by it in a contrary direction to that 



10 » 4.33 of the upper-stream. The water 



12 » (bottom)_ 20.02 



of the under-current was clear and 



