IOWA ACADEMY OF SCIENCE 
173 
(19) fig. 2, plate 5, does not exactly represent the work done because it decom- 
poses in different ways and evolves different amounts of heat. 
The heat watt curve (23) fig. 2, plate 6, is the efficiency curve as x repre- 
sents the total chemical heat and y the watt hours. Curve (22) fig. 1, plate 6, 
is the temperature coefficient curve plotted against the time. It starts out a 
plus dun to the heat taken up in formation of N^-O^ and soon changes to a 
minus and then contrives to fall. 
The cell is of no practical good for closed circuit work after the nineteenth 
hour when polarization sets in. But the cell may be filled with the solution 
again and be nearly as good as new. It is to be noted that the rougher the 
zinc gets, due to the chemical action, the higher the local action is. This is 
due to the fact that the rough dirty zinc will not keep amalgamated. 
DATA NO. 1. 
PHYSICAL PROPERTIES. 
Weight of zinc 1975.7 grams 
Weight of carbon 956.3 grams 
Weight of o'ar 1787.4 grams 
Weight of porous cup 565.4 grams 
Weight of mercury 408.6 grams 
Inner Sol., volume 450 cc spgr 1.3824 
Outer Sol., volume 2000 cc spgr 1.1023 
Surface of carbon 141.99 sq. inches 
Surface of zinc 188.49 sq. inches 
DATA NO. 2. 
ELECTRICAL PROPERTIES. 
Time 
E. M. F. 
P. D. 
C. 
Int. Res. 
Watts 
Int. t 
Ext. t 
R’m. t 
9:40' - 
1.8435 
1.2667 
9.252 
.06532 
11.61 
6.00 
6.00 
7.50 
10:40 
1.7650' 
1.1814 
8.662 
.06982 
9.89 
8.00 
8.00 
7.00 
11:40 
1.7646' 
1.1808 
8.2170 
.07112 
9.68 
9.00 
8.50 ' 
5.50 
12:40 _ 
1.7444 
1.1502 
7.973 
.07447 
9.17 
9.00 
8.50 
4.50 
13:40 _ _ _ 
1.7412. 
1.1345 
■ 7.752 
.07820 
8.76' 
9.50' 
8.50 
5.75 
14:40 
1.7385 
1.1336 
7.724 
.09100 
8.72 
9.50 
9.00 
5.00 
15:40 — ■ 
1.7323 
1.0'753 
7.144 
.09169 
7.64 
10.00 
9.00 
5.00 
16:40 
1.7205 
1.12187 
7.404 
.09616 
8.28 
11.00 
9.50 
4.75 
17:40 _ 
1.7200 
1.0511 
6.951 
.10'520i 
7.29 
10.25 
9.00 
4.50 
18:40 ____ 
1.7110 
1.0242 
6.621 
.1099 
6.75 
9.50 
8.00 
4.00 
19:40 
1.7158 
.9923 
6.578 
.1076 
6.52 
11.00 
11.80 
7.00 
20:40 
1.7092 
.9902 
6. '667 
.1199 
6.69 
12.00 
12.00 
7.00 
21:40 -- __ 
1.7058 
.9741 
.6.091 
.1312 . 
5.93 
13.20 
12.00 
8.00 
22:40' 
1.7020' 
.9220 
5.934 
.1496 
5.47 
14.8 
13.00 
9.00 
23:40 
1.6891 
.8684 
5.448 
.1656 
4.72 
14.8 
13.50 
9.00 
24:40 
1.6640 
.8247 
5.0'33 
.1782' 
4.17 
16.00 
14.50 
11.00 
1:40 
1.5977 
.7950 
4.70'3 
.2075 
3.73 
17.00' 
16.50 
11.00 
2:40 ___ - 
1.5977 
.7555 
4.051 
.2985 
3.05 
18.00 
17.00 
12.00 
3:40 
1.5754 
.6093 
2.929 
.3141 
2.04 
19.00 
18.00 
14.00 
4:40 
1.2900 
.5152 
2.4695 
.3148 
1.26 
19.00 
18.00 
14.00 
5:40 - __ 
.5550' 
.3138 
1.893 
.1274 
.59 
19.00 
18.00 
16.00 
6:40' 
.4846 
.2108 
1.024 
.2655 
.215 
18.60 
17.80 
15.50 
7:40 
.4598 
.798 
.958 
.2388 
.171 
18.00 
17.00' 
14.50 
8:40 
.4189 
.1471 
.938 
.2897 
.138 
19.00 
18.00 
16.00 
9:40 .. 
.4300 
.1475 
.872 
.3119 
.128 
19.50 
19.50 
18.00 
10:40 - 
.3277 
.0952 
.7285 
.3194 
.070 
20.00 
19.00 
16.00 
