146 



Messrs. Carpenter and Jeffreys on [Dec. 8, 



" Report on Deep-sea Researches carried on during the Months 

 of July, August, and September 1870, in H.M. Surveying-ship 

 f Porcupine/" By W. B. Carpenter, M.D., F.R.S., and J. 

 Gwyn Jeffreys, F.R.S. Received December 2, 1870. 



Introduction. 



Preliminary Proceedings , 146 



Equipment 150 



Narrative. 



First Cruise (Atlantic) 152 



Second Cruise (Mediterranean) 162 



General Results. 



Temperature and Composition of Atlantic Water 185 



■Temperature and Composition of Mediterranean Water 193 



Gibraltar Current 203 



General Oceanic Circulation 213 



[At the time at which this Report was presented, it was hoped that the 

 General Summary of Results, of which it then consisted, could be amplified 

 by the insertion of the requisite details, within the time at which the pub- 

 lication of the Proceedings would be due. It has been found, however, 

 that in working out these details so many new points arose suggestive of 

 further inquiries (especially requiring careful comparison of Temperature 

 observations) that, though devoting to them all the time he could com- 

 mand, the Member of the Expedition who is responsible for the whole, 

 save the Narrative of the First Cruise, has found himself unable to com- 

 plete his portion of the Report at an earlier date. Whilst expressing 

 his regret for the delay which has hence arisen, he ventures to hope that 

 some compensation for it will be found in the greater completeness which 

 the Report now possesses ; especially in that Section of it which treats 

 of the Causal Relation between the double currents of the Straits of Gi- 

 braltar and Baltic Sound, and the General vertical Oceanic Circulation. — 

 W. B. C] 



INTRODUCTION. 



Preliminary Proceedings. 



The following Extracts from the Minutes of the Council of the Royal 

 Society set forth the origin of the 'Porcupine' Expedition of 1870, and 

 the objects which it was designed to carry out. 



March 24, 1870. 



A Letter was read from Dr. Carpenter, addressed to the President, sug- 

 gesting that an Exploration of the Deep Sea, such as was carried out 

 during 1868 and 1869 in the regions to the North of the British Islands, 

 should now be extended to the South of Europe and the Mediterranean, 



