164 



PRESSURE. 



From this table it will be seen that at Lyttletoii all the barometers agreed with one 

 another except the ship's barometer, No. 11G3, which appears to have been reading about + 018" 

 too high. 



After this it was impossible to make another general comparison, but ' it is possible to 

 show that the instruments when in the positions in which they were used were in good order. 

 The following is the evidence for the different barometers. 



Cape Evans' Barometers, No. 11 D7 and No. 1667. — The two instruments were compared on 

 five occasions during the two years, mth the following result, after their Kew corrections have 

 been applied. 



Table 92. 



Barometer Comparisons at Cape Evans. 



From these comparisons it is safe to say that both barometers were in good order after 

 landing at Cape Evans. 



Cape Adare Barometer, No. 1156. — Unfortunately the Fuess barometer which was taken to 

 Cape Adare for purposes of comparison was broken in landing. Therefore no comparisons could 

 be made after setting up the Kew barometer, No. 11.56. On the return of this barometer 

 to Lyttleton it was compared with the standard barometer in the observatory there (No. 1121, 

 made by Hughes, London) and found to be exactly correct. It is tolerably safe therefore 

 to assume that it was correct while in use at Cape Adare. This conclusion is made quite 

 certain by the following observations. On Jamiary 3, 1912, the Terra Nova reached Cape 

 Adare at nine o'clock in the morning to take away the party. The observation made on the 

 ship at 8 A.M. was 29-54", while that made at the same time at Cape Adare was 29-537", 

 thus showing that the Cape Adare barometer was in good order. 



The Ship's Barometer, No. 1163.^ — This barometer was compared at Kew before and after 

 the expedition, the comparisons giving — -005 and 000 as the corrections, respectively. From 

 a comparison, however, with the other barometers in Lyttleton and with the Cape Evans' 

 barometer in the Antarctic, this barometer appeared to read -020" too high while used in the 

 Antarctic. The barometer, however, was of the ship's pattern and only graduated to 010", 

 therefore a very high degree of accuracy is not to be expected. In reducing the readings 

 of this barometer I have used a correction of — -010 as being the mean of the corrections 

 found in England and in the Antarctic. 



Framheim Barometer. — When the results of the pressure observations at Cape Evans and 

 Framheim were first examined, it caused great surprise to find that the pressure at Framheim 

 was so much lower than at Cape Evans. Framheim is further south than Cape Evans and 

 has a much lower average temperature, therefore for both these reasons one expected the 

 pressure at Framheim to be the higher. Although there was no reason to doubt the accuracy 

 of the barometers at either Cape Evans or Framheim, it was felt that a comparison of the 



