NOTES ON DEEP SEA SOUNDINGS. 63 



will Jloiv in and rise to the surface, so that the minimum tempera- 

 ture of the sea during the S.W. monsoon will be nearer the sur- 

 face than it is in the N.E. monsoon. 



" It appears then to be evident that as the China Sea is cut off 

 from the general circulation of the Pacific (the minimum tempera- 

 ture of 36°*1, being at a depth of about 900 fathoms in that ocean), 

 the ridge which separates it from the Pacific is probably between 

 700 and 1,000 fathoms." 



(II.) These observations on temperature and evaporation are 

 most valuable, as will be seen in consideration of another paper 

 to which attention ought to be directed, viz. : — " Summary of 

 Recent Observations on Ocean Temperatures, made in H.M.S. 

 ' Challenger,' and U.S.S. ' Tuscarora,' with their Bearings on 

 the Doctrine of a General Oceanic Circulation, sustained by 

 Difference of Temperature," read in June last, and published in 

 the August number of the Proceedings of the Eoyal Geographi- 

 cal Society, by William B. Carpenter, M.D., LL.D., Corre- 

 sponding Member of the Institute of France. Notwithstanding the 

 different conclusions of Professor Wyville Thomson {see "Depths 

 of the Sea"), Dr. Carpenter haslongbeen an advocate of thedoctrine 

 stated in this summary, and he sees in the facts meutioned in the 

 Eeports from Sydney and Hongkong, an abstract of which has 

 now been laid before this Society, a strong confirmation of his 

 views. It will be impossible now to enter fully into his argu- 

 ments ; but those who are desirous of studying them may find 

 their exposition in the memoir named and in his previous papers. 

 But, a few examples of the areas nearest to ourselves may be 

 properly cited here. 



In relation to the Antarctic Ocean which the "Challenger" 

 visited, we have these facts. Leaving Kerguelen's Land, and 

 passing some icebergs, she entered the pack-ice in 65° 30' S. 

 latitude, and on 18th February obtained a Sounding in 65° 42' S. 

 and 79° 49' E. Here, says Dr. Carpenter, the superficial stratum 

 was cooled down by the melting of ice several degrees below the 

 substratum on which it is floated. The temperature at the edge 

 of the pack was always between 28° and 29°, just sufficiently 

 warm to melt the salt-water ice very slowly, whilst at a short 

 distance the surface water was found to be at 32°, coming down to 

 29° at a depth of 40 fathoms, and so continuing to 300 fathoms, the 

 depth at which the icebergs float. Below this there is a tem- 

 perature of 33° or 34°, and again a deep stratum below of glacial 

 water. Captain Nares thought the bottom temperature would 

 be 31° ; but Dr. Carpenter had met with a bottom temperature 

 of 29° • 5 in the Faroe Channel, in the Atlantic, and therefore 

 thinks 29° nearer the mark. " The notion " (he says) " that in 



