NARRATIVE OF THE CRUISE. 
909 
The soundings &c. obtained were divided into two sections — 1st, from Monte Video 
to Tristan da Cunha ; 2nd, from Tristan da Cunha to Ascension (see Diagrams 6 and 7). 
Between Monte Video and Tristan da Cunha twelve soundings, eleven temperature 
soundings, and seven trawlings were obtained. 
In the western part of the Monte Video-Tristan da Cunha section, the depth 
varied from 2900 to 2440 fathoms, and in the eastern part from 1715 to 2200 fathoms. 
The temperature at the bottom in this section was peculiar. In the western part 
temperatures of from 32° ‘3 to 33° T were registered, a colder result than any previously 
obtained except in the immediate neighbourhood of the Antarctic regions. In the eastern 
or shallower part of the section the bottom temperature varied from 34° to 35°'8. 
In order to ascertain the exact thickness of this cold stratum, five or six ther- 
mometers were on each occasion attached to the sounding line at intervals of 200 
fathoms from each other and from the bottom thermometer. From their readings it 
appears that there is, in the western or deeper part of the section, a stratum of water 
below the temperature of 33°, the average thickness, or height above the bottom, of 
which is 400 fathoms. Above 400 fathoms the temperature increases until the 
isotherm of 35° is reached at an average depth of GOO fathoms from the bottom, 
an increase of 2° in 200 fathoms. Between the isotherms of 35° and 40° the 
average distance is 1500 fathoms across the whole section; that is, only a change of 
5° per 1500 fathoms. 
The surface temperature varied from 73° to 64° across the section. 
The serial temperature soundings showed that the isotherm of 40° was on an average 
400 fathoms from, and fairly parallel with, the surface, except in the neighbourhood 
of the coast of South America. The isotherms above 40° were parallel with that 
isotherm. At Station 333 temperature observations were obtained within a few miles 
of those previously obtained on the voyage from Bahia to the Cape of Good Hope, in 
October 1873, at Station 133, and the results at 75 and 100 fathoms were found to 
be identical on both occasions, notwithstanding a difference of 10° in the temperature 
of the surface owins; to the different seasons in which the observations were made. 
Below 100 fathoms a good comparison could not be made, as in October 1873 serial 
temperatures were only obtained to that depth at Station 133, but from a comparison 
made with the results then registered on each side of that Station, it appears that the 
calculated results agree fairly well with those actually obtained. 
The general direction of the surface current was southeasterly. 
In the section from Tristan da Cunha to Ascension, nine soundings, nine serial 
temperature observations, and four dredgings were obtained. 
The soundings in this section show that a ridge extends between Tristan and 
Ascension Islands separating the deep water of the western part of the South Atlantic 
from that of the eastern part. The shallowest sounding obtained on this ridge was 1240 
