578 



Dr. W. B. Carpenter on the 



[June 13, 



much from the surface-stratum, as from a stratum a little below it*, so the 

 current which is (as it were) sucked-iu through the Strait to supply the 

 excess of evaporation in the Mediterranean should be drawn from a sub- 

 surface stratum, and should thus bring with it a lower temperature, 



64. On our entrance into the Mediterranean, we kept in the first in- 

 stance along the African coast, and took frequent observations of surface- 

 temperature ; but we found that we soon lost all indication of the depres- 

 sion observed within the Strait, the thermometer never falling lower than 

 70° ; so that this cold in-current speedily loses its peculiar character by 

 mingling with the general body of Mediterranean water. 



Part III. 



Physical Researches in the Mediterranean. 



65. Temperature. — The Temperature-phenomena of the Eastern basin 

 of the Mediterranean were found to correspond in all essential points with 

 those previously determined in the Western. The limitation in the thick- 

 ness of the stratum superheated by direct insolation, and the almost exact 

 uniformity of temperature beneath this stratum down to the greatest 

 depths, are features no less characteristic of the former than of the latter, 

 — being, in fact, yet more remarkable in the circumstance that the range 

 of depth in the Eastern basin is about 500 fathoms greater than in the 

 Western, some parts of its bottom lying at nearly 2200 fathoms depth 

 from its surface. But certain differences were also noted which are suffi- 

 ciently important to deserve being stated in detail. 



66. It should be mentioned, in the first place, that the heat of the 

 latter part of September 1871 was felt at Malta to be peculiarly oppres- 

 sive, the temperature of the air occasionally rising to 90°, and that of the 

 sea to 80° ; and that this high temperature did not suffer much reduction 

 as we proceeded towards Egypt during the first fortnight of October. On 

 the 3rd of that month, in Lat. 35° 54' N. and Long. 16° 23' E., the sur- 

 face-temperature of the sea was still 80°; and on the 11th, in Lat. 32° 

 17 J' N. and Long. 26° 44' E., it was 79° : at the former of these stations 

 the 5o^0?«-temperature at 1650 fathoms was 56°, — thus corresponding 

 exactly with the bottom-temperature which we obtained last year at 1 743 

 fathoms (in Lat. 36° 31' N. and Long. 15° 46' E.) a little to the east of 

 Malta, — and at the latter it was 56°*7 at 1970 fathoms. 



67. A series of Soundings was made (at my request) by Capt. Nares 

 at each of these Stations, for the determination of the Temperature at suc- 

 cessive intervals of 10 fathoms, from the surface down to 100 fathoms ; 

 and below this at intervals of 50 fathoms, until the depth should be 

 reached at which the temperature becomes uniform down to the bottom. 

 The results of these soundings are given in Columns III. and IV. of the 



* See Maury's 1 Physical Geography of the Sea,' § 387. 



