350 Wisconsin Academy of Sciences, Arts, and Letters. 
layers of phosphorus pentoxide and glass wool rammed fairly 
tight and approximately 2 c. m. in depth each. At V is a by¬ 
pass, Opening of stopcock Y permits the gas to go through 8, 
a tube 15 c. m. long and 2 c. m. in diameter filled with alternate 
layers of phosphorus pentoxide and glass wool, then through 
pinckcock R into the protection train 14, 15, 16, and 17, which 
consists of empty trap bottles alternated with concentrated sul¬ 
phuric acid and caustic soda solution. The end of the train is 
attached to a suction pump. When the train is filled with 
hydrochloric acid gas, cocks Y and R are closed, X, S j , T! and 
X opened and the gas absorbed in the benzene in flask 9, which 
was fitted with a securely fitting three-hole pure gum rubber 
stopper. The benzene had previously been gently distilled over 
from the retort 10, into flask 9, where it was condensed by ex¬ 
ternal application of snow. The benzene used was Schu- 
chardt’s thiophene-free preparation. It stood one month over 
a large quantity of phosphorus pentoxide from E, de Haen and 
then was poured into retort 10, where it stood twenty-four 
hours over bright sodium chips before being distilled from 
them. In order to displace the air in the retort 10 and flask 9, 
suction was applied to the end of the train and benzene evapor¬ 
ated to take its place. Oxidation of the metals which remained 
in flask 9 over night was thus prevented. The stopper of re¬ 
tort 10 was specially ground in by myself, set in with vaseline 
and wired tightly to the retort. The distillation was conducted 
with a, very small flame. The phosphorus pentoxide tubes 11, 
12, and 13, protect flask 9. They are of the same dimensions 
and filled in the same manner as tube. 8 already described. 
The hydrogen chloride 1 was passed slowly into the benzene 
after running for fifteen minutes through the by-pass. At 9 :42 
a. m. Thursday, Jan. 15, all the zinc—both the c. p. wire and 
stick given me by Mr. Falk and the Schuchardt’s stick zinc 
which I used originally—gave off gas. For a time gas came 
off faster and faster, the platinized zinc acting exactly like the 
other zinc except where the platinum coating protected it, and 
there no gas was evolved. Xo action was visible upon the mag¬ 
nesium, neither a tarnish nor gas evolution. The gradual 
