OCEANIC CIRCULATION. 231 



and equatorial regions was discredited by this supposed 

 discovery. 



Drs. Carpenter and Wyville Thomson, however, have 

 been able to show that no such relation exists. There 

 are vast submarine regions of the Atlantic where the 

 temperature of the water is far lower than the constant 

 and uniform temperature believed in by Sir John Her- 

 schel. The temperature is, indeed, in places, as low, 

 or veiy nearly so, as the freezing-point of fresh water, 

 under a surface-temperature 20 degrees or so higher. 

 But in other regions having the same surface-tempera- 

 ture the depths are 10, 12, or 14 degrees higher than 

 that of freezing fresh water. Moreover these relations 

 are constant, so far as the deep water is concerned. 



Now, there can be only one interpretation of the cir- 

 cumstances here mentioned. If the depths of the ocean 

 were unmoved by any process of submarine circulation 

 there can be no question that a general uniformity of 

 deep sea temperature would prevail in given latitudes. 

 We should not find the bottom water in one region 1 3 

 or 14 degrees warmer than the water in a closely adja- 

 cent region. We have only to inquire what is the case 

 in inland seas where no great influx of water of alien 

 temperature can take place, to see that this must be so. 

 Take, for instance, the Mediterranean. Here we learn 

 from Dr. Carpenter's recent researches that ' the tem- 

 perature at every depth beneath 100 fathoms is found 

 to be uniform, even down to a bottom of 1,900 fathoms ; 

 as had, indeed, been previously ascertained by Captain 

 Spratt, although his observations, made with thermo- 



