370 Mr. J. Y. Buclmnan [May 29, 



The advaotage of being able to use the same thermometers for 

 determining the bottom temperature at so many different localities, 

 does not require to be pointed out to any scientific man. 



It was part of the regular routine of a station to determine the 

 temperature of the intermediate water from the surface down to 

 1500 fathoms at every hundredth fathom. In addition, that of the 

 water between the surface and a depth of 100 fathoms was generally 

 determined at every tenth fathom. Sometimes it was determined at 

 every twenty-fifth fathom from the surface to a depth of 300 fathoms. 

 It was usual to use from six to eight thermometers on the line at 

 once, so that the temperature at every hundredth fathom down to 

 1500 fathoms was effected in two operations. The temperatures at 

 closer intervals, in the water near the surface, were determined also 

 at the rate of eight per operation. Therefore in obtaining the inter- 

 mediate temperatures, first 1500 fathoms had to be run out and 

 hauled in ; then 700 fathoms ; then one or perhaps two shorter 

 lengths, according to the number of temperatures near the surface 

 which were desired. This service alone entailed the handling of 

 something like 2500 fathoms of line, and, as we have seen, during 

 the whole voyage only two accidents occurred to the temperature 

 line. The following table shows the work which was done by the 

 temperature line. 



The number of stations which furnished these 4899 temperature 

 observations was 262, which gives an average of 18*7 observations 

 per station. A full station in deep water included either three or 

 four operations and furnished from 20 to 30 temperatures. At many- 

 stations the depth was less than 1500 fathoms, and it was not neces- 

 sary always to take temperatures at such close intervals. The main 

 result of the above table is to show that the enormous number of 

 nearly five thousand deep-sea temperatures was obtained with an 

 expenditure of only eight thermometers and one line. It was at the 

 rate of 612 observations for every thermometer lost. 



Although specimens of the earliest pattern of Negretti and 

 Zambra's reversing thermometer were received on board the Challenger 



