450 
MR. GEORGE W. WALKER ON THE DEPENDENCE OF THE 
Ammonia Gas, put in 13th June, 1902. 
Date. 
Temperature 
of 
tubes. 
Temperature 
of 
manometer. 
Ratio. 
Corrected 
Multiplied by 
ratio. 
1 + -00385^. 
1+ - 00390/. 
1+ -00395/. 
17th Jane 
"C. 
11-8 
°C. 
15-5 
8-139 
8-160 
8-530 
8-535 
8-540 
17 th 
11-8 
15-6 
8-140 
8-161 
8 - 5.30 
8-535 
8 - 540 
18th 
56 ■ 25 
18-2 
6-997 
7-012 
8-530 
8-550 
8-570 
18th 
56-0 
18-2 
7 - 003 
7-018 
8-530 
8-550 
8-570 
19th 
60-6 
20-2 
6-887 
6-904 
8-515 
8-535 
8-555 
19th 
if 
GO-3 
20-4 
6-904 
6-921 
8-530 
8 - 550 
8-570 
20 th 
75-5 
19-4 
6-597 
6-610 
8-530 
8-555 
8-580 
20th 
if 
76-4 
19-4 
6-572 
6 - 585 
8-525 
8-550 
8-575 
20th 
76-8 
19-8 
6-562 
6-575 
8-520 
8-545 
8-570 
23rcl 
90-5 
22-3 
6-291 
6-305 
8-500 
8-5.30 
8-560 
23rd 
if 
90-5 
22 - 7 
6-283 
6-298 
8-490 
8-520 
8-550 
23rd 
if 
90-4 
22-8 
6-287 
6-302 
8-495 
8-525 
8 - 555 
24th 
if 
32-0 
23-6 
7-580 
7-607 
8 - 545 
8-555 
8-565 
24th 
if 
31-95 
23-9 
7-574 
7-602 
8-540 
8-550 
8-560 
24 th 
if 
31-75 
24-2 
7-575 
7-603 
8-530 
8-545 
8-555 
25th 
23-75 
23-9 
7-780 
7-810 
8-525 
8-535 
8 - 545 
25th 
if 
23-65 
23-8 
7-777 
7-807 
8-515 
8-525 
8-535 
25th 
if 
23-75 
23-8 
7-781 
7-811 
8-525 
8-535 
8-545 
Mean. 
Greatest variation . . . 
8-523 
+ -022 
- -033 
8-540 
+ -015 
- -020 
8-557 
+ -023 
- -022 
; 
i 
I was unable to make a final observation at 12° C., owing to the fact that one of 
the glass joints had cracked during the night of the 25th June. However, the 
residts of l7th and 25th June are a fairly good test that no change in tlie gas had 
taken place. 
We may take the ratio as 
8-540 ± -010 
1 + ^ (-00390 + -00003) ’ 
Throughout 2^1 + Jh =120 centims. of mercury 
X = -000178 jier centimetre of mercury (Mascart). 
We thus obtain for the refractive index 
_ ^ (-0003743 ± -00 0 0005) (1 + -000l78p ) jp 
1 + ?(-00390 ± -00003) 76’ 
2 ^ Ijeing expressed in centimetres of mercury at 0° C. 
At 0° 0. and 76 centims. pressure 
= 1 + -0003793 ± -0000005. 
