218 



Messrs. Carpenter and Jeffreys on 



[Dec. 8, 



II. That the evidence of Climatic amelioration increases in propor- 

 tion as we pass Northwards from the neutral area, becoming very decided 

 at the Orkney, Shetland, and Faroe islands ; but that, as was shown by 

 the ' Porcupine ' Temperature-soundings of 1869, the flow of warm water 

 which produces this amelioration extends to a depth of at least 700 

 fathoms. 



III. That this deep stratum of Warm water can be shown, by the corre- 

 spondence in the rate of its Diminution of Temperature with depth, to be de- 

 rived from the neutral area to the south-west ; where, as is shown by the 



Porcupine* temperature-soundings of 1870, it is separated by a distinct 

 " stratum of intermixture " from the deeper stratum that carries Polar 

 waters towards the Equator. 



IV. That the slow north-easterly movement of such a mass of water 

 cannot, on any known Hydrodynamical principles, be attributed to pro- 

 pulsive power derived from the Gulf-stream ; the last distinctly traced 

 edge of which is reduced to a stratum certainly not exceeding 50 fathoms 

 in depth, and not improbably less. • 



V. That, on the other hand, this slow Pole-ward movement of the upper 

 warm layer of the North Atlantic, down to the "stratum of intermixture/ ' 

 is exactly what might be expected to take place as the complement of the 

 flow of glacial water from the Polar to the Equatorial area, the two 

 movements constituting a General vertical Oceanic Circulation. 



VI. That there is a strong probability that the quantity of Water dis- 

 charged by the Gulf-stream has been greatly over-estimated, in consequence 

 of the rate of the surface-current having been assumed as the rate of 

 movement through the whole sectional area, which is contrary to all 

 analogy ; whilst there is also a strong probability that there is a reverse 

 undercurrent of cold water through the Narrows, derived from the Polar 

 current that is distinctly traceable nearly to its mouth. The upper stratum 

 of this southerly current comes to the surface between the Gulf-stream 

 and the coast of the United States ; whilst its deeper and colder stratum 

 underlies the Gulf-stream itself*. 



VII. That there is a strong probability that the quantity of Heat 

 carried off by the water of the Gulf-stream has been greatly over-estimated ; 

 the Temperature-soundings taken during the Cruise of the 1 Porcupine ' in 

 the Mediterranean having shown that the very high temperature of the 

 surface extends but a little way down, whilst the Temperature-observa- 

 tions in the Atlantic show that the descent into a cold stratum beneath 



* That there is a slow southerly movement of Arctic water beneath the Gulf-stream 

 is indicated by the fact that icebergs have been seen moving southwards in direct op- 

 position to its surface-flow, their deeply immersed portion presenting a larger surface 

 to the lower stratum than their upper part does to the more superficial layer, — as in 

 the case of our " current-drag." And similar evidence is afforded by the southward 

 drift of the buoy which was attached to the Atlantic Cable of 1865, but which broke 

 away from it, apparently carrying with it a great length of the wire rope by which it 

 had been attached. 



