568 REGNAULT ON THE 
each other, subjected internally to the same pressure; the one 
however was dry, the other, on the contrary, contained a small 
layer of water. They were left till the following day, to make 
sure of their being at the same temperature ; when the difference 
of level in the two mercurial menisci and the height of the co- 
lumn of water was determined. This last height, reduced to its 
equivalent in mercury, would represent the observed difference 
in the two columns of mercury, if no alteration had taken place 
by capillary action. The effect of this latter cause would there- 
fore be measured by the difference of height in the two mercurial 
menisci, less the value in mercury of the little column of water. 
It was thus found that the wet column, after the correction had 
been made for the weight of the small column of water, was 
raised by the capillary action of the water 0°12 millimetre. 
Table I. shows the results obtained by this mode of proceeding. 
TaBLe I. 
Tempera- Tensions Tempera- Tensions 
ea of the vapour. Difference afte. of the vapour, deausinn 
No. 7. | Observed, | Calculated, No. 7. Observed. | Calculated. 
° mm mm mm ° mm mm mm 
9°73 9°03 | g'o0z | 0°03 38°09 | 49°55 | 49°543 | +0°Or 
9°73 9°05 : 40°28 | 55°73 | 55°733 o"00 
11°64 10°27 - 40°28 55°67 
11°62 Io'lg | 10°200 | —o'o1 40°25 55°55 
11°62 10°23 oe 46°20 75°7 
13°56 r1"62 | 11°575 | +0'05 46°24 75°9 Ac ee 
13°56 11°60 ap ts 46°23 75°88 | 76°04 —o'16 
15°56 13°18 | 13°16 +0'02 51°39 98°29 “2 oe 
15°58 | 13°16 . “ 51°39 | 98:23 | 98541 | —0'31 
17°67 15°07 es aie 58°62 | 139°05 ae a 
17°68 15°13 et ee 58°56 | 13881 | 1397119 | —O°31 
17°68 15705 | 15°052 0°00 58°49 | 138°25 He #3 
19°36 16°74 | 16°716 | 0°02 21°08 18°66 = it 
19°35 16°70 B = 21°08 18°64. | 18°585 | 0°06 
21°41 18°94 o. . 21°08 18°62 bi 4e 
21°41 18°96 | 18°965 0"00 8°79 8°44 A 2 
21°41 19°00 ae 8°79 8°44 8454 | —O°or 
23°66 21°74 | 213°736 000 8°79 8°46 = 5 
23°67 21°78 Pit 4°32 6°32 ac ~ 
23°66 | 21°76 : 4°33 6°30 6'239 | +006 
26°01 25°05 os ss 4°34 6°28 +. oe 
26°02 25°07 | 25°059 | +o°or 4°94 6°54 
26°02 25°07 vie ae 4°97 6°54. an oe 
28°80 29°44 | 29°437 "00 5°00 6°56 6°534 | +0°03 
28°80 29°46 an a 6°15 7°06 oe . 
31°95 35°27 35°259 | +o'oI 6°17 7°10 77081 | +0'02 
31°95 35°29 ee ss 6°19 712 °. on 
34°79 4129 | «- ve 6°22 7°14 ee a 
34°75 4125 | 41252 ejn0 75° 7°73 7745 | —o‘or 
34°75 | 4123 . 75% 7°69 . . 
38°09 | 49°51 | 7°52 age 
