THE PRINCE OF MONACO 125 



struck one of the main drains of overflow from the abysmal 

 regions of the Mediterranean," where the water at the bottom 

 is a good deal warmer than in the Atlantic. The Mediter- 

 ranean is so situated that it loses more water by evaporation 

 from its surface than is supplied to it during the year by rain 

 and rivers. If the Straits of Gibraltar were closed, it is 

 calculated that the Mediterranean would shrink in size and 

 increase in saltness till it attained a condition similar to that 

 of the Dead Sea. The deficiency due to over- evaporation is 

 compensated by the surface current of Atlantic water which 

 it is well known enters at the Straits, and every gallon of this 

 Atlantic water brings with it about six ounces of salt, which 

 remains in the sea when the water evaporates, and would 

 tend to accumulate as water of high density at the bottom 

 were it not that it is discharged in a deep current into the 

 Atlantic. This outflow, after passing between Capes 

 Spartel and Trafalgar, naturally follows the deepest channels 

 outwards until it is lost in the ocean. Mr. Buchanan argues 

 that the high temperature obtained outside the Straits at a 

 depth of 800 fathoms on this occasion was due to one of these 

 local rivers of relatively warm and salt water, and he calcu- 

 lates, from a comparison of temperatures, that at that point it 

 consisted roughly of 50 per cent, of Mediterranean and 50 per 

 cent, of Atlantic water. 



As another example of the Prince's oceanographical work 

 in the neighbourhood of the Azores, we may take the dis- 

 covery in 1902 of the existence of an enclosed basin, appro- 

 priately known as the " Monaco " deep, in which the 

 temperature at a depth of 1,645 fathoms was 5° C. Now, in 

 the open water of the North Atlantic of the neighbourhood 

 the temperature at such a depth ought not to be higher 

 than 3° C. It was evident, then, that the sounding had been 

 taken in an enclosed basin shut off from the water of the 

 surrounding ocean by a lip situated at such a depth below the 

 surface that the minimum temperature of the water which 

 can gain access to it is 5° C. This result was confirmed by 



