606 



Dr. Wi B. Carpenter on the 



[June 13, 



Sea temperature of 39°'2, originally propounded by Sir James Ross, and 

 unfortunately adopted (to be afterwards entirely abandoned) by Sir John 

 Herschel, is then formally propounded by Dr. Miihry, as if it had not been 

 completely exploded by the results of the ' Porcupine ' and other recent 

 Temperature-soundings. 



111. Now the increase of density of Sea- water down to its freezing-point, 

 which may be as low as 25°*4, is as well established as any fact in Physics ; 

 while there is no reliable observation (made with Thermometers protected 

 from the influence of pressure) which indicates a Deep-sea temperature of 

 39 c "2 in either the Arctic or the Antarctic basin. 



112. It will be unnecessary for me to dwell at any greater length on my 

 points of difference with Dr. Petermann ; since it will be obvious to any 

 careful reader of his Memoir, that its main object is to prove the existence 

 of the North-easterly movement of a deep voluminous body of warm water 

 (as distinguished from a surface-drift) in the North Atlantic ; on which 

 point I entirely agree with him. And although he applies to this flow what 

 I cannot but consider the very inappropriate designation of the " Gulf- 

 stream," he expressly guards himself from assigning to the initial force of 

 the Florida Current (or Gulf-stream proper) the whole, or even a principal 

 part, of the power by which this movement is sustained. 



113. But a doctrine of the Gulf-stream has been put forth by my friend 

 and colleague Prof. Wyviile Thomson, to which I regret to find myself in 

 direct opposition : for he regards the North-easterly movement of 

 Dr. Petermann's " deep, voluminous, warm stream " as essentially due to 

 the initial force of the Florida Current ; and attributes its ameliorating 

 effect on the temperature of the North Atlantic and Arctic seas to the heat 

 which the Gulf-stream proper has brought from the Intertropical zone. 

 "The basin of the North Atlantic," he says, " forms a kind of cul de sac ; 

 " and while a large portion of the Gulf-stream water, finding no free outlet 

 " towards the north-east, turns southwards at the Azores, the remainder, in- 

 " stead of thinning-ofT, has rather a tendency to accumulate in the northern 

 " portions of the trough. We accordingly find that it has a depth, on the 

 " west coast of Ireland, of at least 800 fathoms, with an unknown lateral ex- 

 (S tension." Further, he says, in " the shallow, including the Hebrides, the 

 " Orkney and Shetland Islands, and the Faroes, stretching westwards and 

 " northwards nearly to Scotland, the average depth is about 500 fathoms ; 

 " and the Gulf-stream, which has a depth in these latitudes in summer of 

 " from 600 to 700 fathoms, occupies the whole of it, giving an abnormal 

 " temperature of something like 12° C."* 



114. The foregoing sketch of the recent history of this inquiry presents 

 for our consideration four principal Doctrines respecting the causes of the 

 abnormally high Temperature of the British Islands, and of the ameliora- 



* See his Lecture "On Deep-Sea Climates," in 'Nature,' July 28th, 1870, and his 

 "Address to the Scottish Meteorological Association," in 'Nature,' July 27th, 1871. 



