188 



Messrs. Carpenter and Jeffreys on [Dec. 8, 



I. Those taken in the " Chops of the Channel," about Lat. 48° N., cor- 

 responding closely in geographical position with several of those of the 

 Second Cruise of 1869. 



II. Those taken off the Atlantic Coast of Spain and Portugal, between 

 Lat. 42|° N. and Lat. 37° N. 



III. Those taken within the embouchure of the Strait of Gibraltar, ex- 

 tending westerly as far as Cape St. Vincent and Tangier, and lying between 

 Lat. 37° N. and 35|° N. 



79. The first two sets may be advantageously compared with each other, 

 and with a Set of Bottom and Serial (No. 42) Soundings taken last year 

 nearly in the same locality as the first ; these are presented in the fol- 

 lowing Table. 



Temperature of the Sea at different Depths near the Western margin of 

 the North-Atlantic Basin. 







I. 







II. 







m. 





Chops of the Channel, 1869. 



Chops of the Channel, 1870. 



Coast of Spain and Portugal 





Depth, 



Surface- Bottom- 





Depth, 



Surface- 



Bottom- 





Depth, 



Surface- 



Bottom- 



No. 



in 



Temp. 

 °Fahr. 



Temp. 

 Fahr. 



No. 



in 



Temp. 

 Fahr. 



Temp. 

 Fahr. 



No. 



in 



Temp. 



Temp. 

 °Fahr. 





fathoms. 





fathoms 





fathoms. 



°Fahr. 



34. 



75 



660 



497 



7. 



93 



61-0 



51-3 



10. 



81 



60-5 



53-5 



35. 



96 



63-4 



51-3 



5. 



100 



62-3 



51-5 



12. 



128 



61 5 



52-5 



42. 



250 



62-6 



50-2 



8. 



257 



60-7 



50-0 



19. 



248 



64-7 



51-7 



42. 



300 



62-6 



49-6 



2. 



305 



615 



48-7 



11. 



332 



60-5 



515 



42. 



350 



62-6 



49-1 



6. 



358 



62-0 



50-3 



17. 



340 



67-0 



50-5 



42. 



450 



62-6 



47-6 











14. 



469 



69-7 



51-5 



39. 



557 



63-0 



47-0 



9. 



539 



64-0 



48-0 











42. 



600 



62-6 



45-5 











21. 



620 



67-3 



50-5 



36. 



725 



63-9 



43-9 



4. 



717 



61-5 



45-5 



22. 

 15. 



718 

 722 



66-5 

 675 



50-5 

 49-7 



42. 



750 



62-6 



42-5 











17a. 



740 



667 



49-0 



42. 



800 



62-6 



420 











23. 



802 



66-5 



49-3 



42. 



862 



62-6 



39-7 











16. 



994 



69-5 



40-3 



38. 



1000 



64-0 



38-3 











18. 



1065 



650 



39-7 



38. 



1250 



640 



377 











17. 



1095 



68-0 



397 



Between Nos. I. and II., as might be anticipated, the accordance is 

 extremely close ; and this accordance extends to the upper stratum (ex- 

 cluding the actual surface) in No. III., allowance being made for difference 

 of Latitude. Notwithstanding that the surface-temperatures in No. III. 

 range as high as 69 0, 7, the average excess at depths between 81 fathoms (at 

 which the superheating of the surface has but little effect, § 87) and 350 

 fathoms is not above 2°, the reduction of temperature encountered in de- 

 scending this upper stratum being very small in each case. But whilst 

 this slow rate of reduction continues in No. III. down to 800 fathoms, — 

 the bottom-temperature at 802 fathoms being 49 0, 3, — the reduction is more 

 rapid in Nos. I. and II., so that the temperature of 45°* 5 is reached in 

 the one at 600 fathoms, and in the other at 717 ; whilst at 800 fathoms 

 in No. I. the temperature has fallen to 42°. Below 800 fathoms, how- 



