318 Wisconsin Academy of Sciences , Arts, and Letters. 
diffused daylight. It.was shown by Ei. A. Parnell 6 that dry 
hydrogen sulphide will not act upon dry salts of lead, mercury 
or copper. In a footnote Andrews 7 states that dry chlorine at 
ordinary temperature does not act upon zinc, copper, or iron fil¬ 
ings ; and that dry bromine at ordinary temperatures does not 
act upon dry metals. In 1867 Kolb 8 found that dry oxides 
and hydroxides of calcium, barium, magnesium, sodium, and 
potassium do not gain weight in an atmosphere of dry carbon- 
dioxide. 
Wanklyn * 1 in 1869 noted that sodium and chlorine do not 
unite, but did not state whether moisture alone added would 
cause combination. Dubrunfaut 2 thought that water favors the 
combustion of carbon; but Dumas 3 showed that pure graphite 
is completely consumed in oxygen dried by sulphuric acid. 
The work of Dumas, however, loses significance since it has 
been experimentally demonstrated 4 that gases dried over sul¬ 
phuric acid still give up a weighable amount of water to phos¬ 
phorous pent oxide. In 1876 Oowper 1 allowed dry chlorine to 
act upon metals and found that presence of moisture was neces¬ 
sary for action to take place. Pringsheim 2 in 1887, and Dixon 
and Harker 3 in 1890, showed that dry hydrogen does act upon 
dry chlorine in absence of moisture, though more slowly than 
with water present. Dixon 4 and Victor Meyer 5 6 7 have shown 
that the union of hydrogen and oxygen is facilitated by pres¬ 
ence of water vapor. Holt and Simms 6 find that dry oxygen 
does not act upon dry sodium or dry potassium; and Baker 7 
finds the same for carbon, phosphorous, sulphur and tellurium, 
6 B. A. Reports, 1841, 51. 
7 Trans. Royal Irish Acad. 1842, 19, 398; also Scientific Memoirs, 1889, 
p. 90. 
8 Compt. Rend. 1867, 64, 861; also DeBray, Ibid. 1848, 26, 603. 
i Chem. News, 1869, 20, 271. 
* Compt. Rend. 1871, 73, 1895. 
3 Compt. Rend. 1872, 74, 13. 
4 .000002 gr. water per litre of air. Morley. Am. Jr. Sci. 1885 [iii] 30,140. 
1 Trans. Chem. Soc. 1876. 
2 Ann. Chim. Phys. 1887, 421. 
3 Owens College Researches 1. 
4 Phil. Trans. 1884. 
5 Berichte d. D. C. Gs. 1893. 
6 Trans. Chem. Soc. 1894. 
7 Phil. Tran. 1888. 
