(28 ) 
D 
A | zL | <2 B z,B | Height | Corr. Mean | Corr. ae Corr. for Cn 
E | mercury.) leakage. | temp. | temp. oe gi heek. | 
I, | 2123.36 | 23.68 slan! 0.00 | 179.66 AE 6.05 | — 2.38 209648 
| II, | 2123.61 | 42.37 ttl 0.00 | 17°.60 |— 6.02} — 2.38 2000.2 
mn 
All the lengths are expressed in cms. 
The heights of the mercury found on different days are combined 
in the following table, which also gives the difference of those cal- 
culated heights in the two systems. 
Table of comparisons. 
| Date. | Time. System I. | System II. | Difference. | 
28 June 4.36 2096.48 cm. 2096.23 cm. + 0.25 em, 
>» » 5.14 2095.33 » 2095.45 » — 0.12 » 
29 » 3.50 2107.03 » 2107.15 » — 0.12 » 
>» » 4.30 2106.13 » 2106.27 » — 0.14 » 
Din 5.07 2104.25 » 2104.41 » — 0.16 » 
30 » 2.25 2117.55 » 2118.01 » — 0.46 » 
» » 3.02 2117.42 » 2117.73 » — 0.51 » 
pp 8.42 2116.01 » 2116.23 » — 0.22 » 
» » 4.13 2115.23 » 2115.51 » — 0.28 » 
oy. 4.49 2113.81 » 2113.75 » + 0.06 » 
5 July 4.00 2118.76 » 2118.53 » + 0.23 » 
» » 4.25 2117.67 » 2117.96 » — 0.29 » 
» » 5.00 2116.59 » 2116.64 » — 0.05 
For the mean difference at one measurement we find therefore 
0.24 e.m., this amounts to of the pressure measured. But 
1 
8800 
there appears to be a systematic error in the observations; for the 
reading in the second system is on an average 0.13 c.m. higher 
than in the first system. Perhaps it may be ascribed to the fact 
that all the tubes of the second system are much narrower than 
those of the first, so that if the height of the high menisci at the 
