56 



H. MOHN. 



M.-N. Kl. 



the Pole, the mean error e of a single determination of the height or half 

 the difference between the two determinations and the mean error »i of 

 their mean. ;;/ = e/'^V. 



The general mean of;;/ is + 20 m. The mean for the Barrier is ± 11 m., 

 and for the Plateau ± 28 m. 



The values of >n are thus distributed : 



From o to lo m. 13 cases 



• II— 20- 8- 



21 — 30 - 5 - 



31 — 40 - o - 



41 - 50 - o - 



51 — 60 - 2 



From 61 to 70 m. i case 



71 — 80 • a - 



81 — 90- o- 



91 — 100 - I - 



loi — 140 - I - 



The mean errors found for the computed heights are composed of 

 different errors arising from the circumstances under which the obser- 

 vations were made. 



The aneroid is read to 0.05 inches or 1.25 m.m. The mean error may 

 be taken to be ± 0.625 ^ri-ni. 



The corrections for the readings of the aneroid have been found, 

 p. 51, to be 



for the Barrier for the Plateau 



± 0.5 mm. ± 1.2 mm. 



Hence the mean error of a single determination of the pressure: 

 + V 0.625'^ + 0.52 = + 0.8 mm. ± I' 0.6252 *- 1.2- = + 1.35 mm. 

 and of a set of two determinations of which the mean has been taken, 

 ± 0.8 Y 2 = + 1. 13 mm. zt. 1-3512 = ± 1.91 mm. 



The resulting error of the height, from formula (3) 



t = — 16", b = 740 mm. t = — 15O, b = 520 mm. 



m = + II m. 



m ^ + 23 m. 



