1915- No. 5. ROALD Amundsen's antarctic expedition: meteorology. 



igii 



Xov 



Dec. 



13 

 16 



18 



26 



29 

 30 



Corr. 



99-39 

 99- n 

 99.28 

 99.11 

 98.67 

 95.86 



95-67 

 89.06 

 89.78 

 90.50 

 91.56 



91 39 

 91.28 

 QI.06 



ni m. 

 743-6 

 737-7 

 740-7 

 736.1 

 724.6 



6543 

 603.6 



507-5 

 521.6 

 536-0 

 557-9 

 554-3 

 552-0 



547-5 



744-2 

 737-9 

 741.7 

 737-9 

 723-9 

 6527 

 602.0 

 506.7 

 519-4 

 532.1 

 553-7 

 551-2 

 548.6 



542.3 



m.m 



- 0.6 



- 0.2 



- I. o 



- 1.8 

 0.7 



.6 

 .6 

 H- 0.8 

 + 2.2 



- 3-9 



- 4.2 



- 3-1 

 ^ 3-4 



5-2 



+ 

 + 



4 



rgii 



Corr. 



Dec 



13 



14 



90.53 

 90.33 

 90.03 

 89.64 

 89.06 

 89.06 

 89.06 

 88.94 



89-33 

 89.61 

 89.78 



89.75 

 89.91 

 89.61 



- 3.2 



- 1.7 



-r- 2.1 



- 3-2 

 -i- 2.0 



^4.6 

 - 4.6 



^4-8 



- 6.0 

 -- 5.1 



^ 4.7 

 + 5-4 



- 6.0 



Separating the readings of the aneroid and the corrections into groups 

 of different pressures, and taking the means for each group, we have 



At 

 Corr. 



It 



740-4 723-9 652.7 602.0 549.0 530.2 516.0 504.2 m.m. 



— 0.9 — 0.7 ^ 1.6 -t- 1.6 4 2.7 — 2.7 



:r 0.5 — — — ^ 1.3 ^ 0.8 



4 I I I 4 4 



- 4-5 

 in I.I 



/ 



+ 3-8 



± 1.6 

 6 



d is the mean of deviations of the observed corrections from the mean of 

 the group. /; is the number of observations in each group. 



The corrections evidently increase with decreasing pressure, with 

 the exception of the last group. The accuracy of the determination of the 

 corrections is characterised by the value of d, and it increases with de- 

 creasing pressure. On the Barrier, i** group, the mean deviation is half 

 a millimetre, but on the Plateau it reaches one millimetre and upwards. 

 These numbers may be taken as the probable error of the corrections of 

 the aneroid. 



The corrections for each group were plotted as ordinates against the 

 corresponding readings of the aneroid as abscissae, and a broken line 

 drawn through the upper end of the ordinates. From this line could be 

 read the corrections for every reading of the aneroid, from the 7*'^ November 

 to the 17*^^ December 1911. 



The observed pressure on the 6*^*^ November, on the Barrier, was 

 744 2 m.m., and the correction found from the hypsometers — 0.6 mm. 

 The comparisons made at Framheim in October gave for this reading the 

 correction — 1.8 mm. Between the start on the 20**^ October and the 

 6'^ November the correction has thus changed from — 1.8 m.m. to — 0.6 m.m. 

 or -^ 1.2 in 17 days or + 0.071 m.m. per day. By adding 0.071 m.m. per 



