\ND THE FISH THEREOF. 



forth from the sea-bed. The water is also colder than at similar depths 

 elsewhere ; thus, on the Dalmatian coast, nowhere less than 1 2,°'$ cent. ; 

 opposite Ragusa, in the high sea, in 125 fathoms, i3° - 9 cent. ; Lissa, in 

 60 fathoms, i4°cent. ; Channel of Brazza, in 40 fathoms, i3°'8 cent.; whereas, 

 in the Gulf of Fiume, in 30 fathoms, 12 cent., and even 1 1° cent.; off Arbe, 

 in rather deeper water, io° cent.; and near Segna, g°-y cent., this being the 

 approximate temperature of the sweet-water springs at Fiume. 



9. In the Gulf of Fiume and Channel of Segna the surface-waters have 

 a smaller proportion of salt, owing to the Fiumara and other torrents ; the 

 greatest amount of saline matter is found in 30 fathoms, below which again 

 there is a decrease, owing to the submarine springs. The increase from the 

 surface downwards is very rapid. 



10. The high sea contrasts with the foregoing conclusions (No. 9), by 

 higher temperatures, and higher degree of saltness in deep waters. 



11. In the Gulf of Trieste the highest temperatures are to be met with 

 throughout, owing to the shallowness ; lowest degree of saltness on the 

 surface, and below 5 fathoms a relatively high degree of saltness, showing 

 that the supply of sweet water from the Po and other water-courses does 

 not mix with the sea water, but remains upon the surface. 



12. The variations of the temperature in deep water, which is impervious 

 to the direct effect of light or radiation, are necessarily slow, for the simple 

 reason that such effect can only make itself felt by degrees. The fact, how- 

 ever, of such variations taking place on days when the sea has been calm 

 for some time past, seems to point at the influences of vertical currents, on the 

 theory of Dr. Carpenter, created by the evaporation of the surface waters, 

 bringing forth an increased percentage of saltness, greater specific gravity, 

 and consequent tendency downwards. This motion is further increased by 

 the influence of the ground-springs, whose lighter waters naturally tend to 

 the surface, thus creating a current upwards, and necessarily a corresponding 

 current downwards, by which means the warmer surface waters are brought 

 to the lower depths, thereby influencing their temperature. 1 



1 The results of these valuable investigations have been recapitulated in a publication : 



