342 Wisconsin Academy of Sciences, Arts, and Letters. 
NOTE ADDED JAN. 19, 1903. 
At the Washington Meeting of the American Chemical So¬ 
ciety, December 30, 1902, President Ira Pemsen stated that 
he had been unable to get hydrogen by acting upon dry zinc 
with hydrogen chloride dissolved in dry benzene. He said that 
the zinc was acted upon very slightly for a period not exceeding 
two minutes, after which the zinc remained unacted upon. His 
interpretation was that as soon as the surface layer of moisture 
on the zinc 1 was used up the action ceased for lack of ions. 2 3 
He further stated that upon opening the flask containing the 
benzene solution to the air, moisture was at once taken up and 
action upon the zinc recommenced but stopped again when the 
moisture was gone. 
After the close of that session I told Dr. Kemsen that I 
should be in Baltimore during the next week and would be 
pleased to see wherein the difference in our experiments lay. 
Oil Monday, Jan. 5, I presented myself to Dr. Bemsen and he 
sent me into the laboratory to meet Mr. K. Gr. Falk who had 
done the experimental work. Mr. Falk put together the appa¬ 
ratus given in Figure 1. 
Flask 1 contained e. p. concentrated sulphuric acid into which 
c. p. concentrated aqueous hydrochloric acid was dropped. The 
hydrogen chloride gas evolved passed through washbottles 2, 3, 
and 4, which contained c. p. concentrated sulphuric acid; and 
then through a phosphorus pentoxide drying tube, 5, into the 
bottle, 6, about two inches in diameter and three inches high 
containing the benzene and the zinc and other metals. Tube 7 
is a phosphorus pentoxide protection tube, and 8 is a washbottle 
containing c. p. concentrated sulphuric acid. 
1 The zinc had been heated to 120 s C. for at least half an hour, as I 
afterward learned from Mr. Falk, a graduate student at Johns Hopkins 
University, who did the experimental work. 
3 If the water ionizes the hydrochloric acid gas we should expect the 
action to continue indefinitely as in the case of the union of dry ammonia 
with dry hydrogen chloride when a trace of moisture is introduced. The 
mere formation of zinc chloride and its solution in a small amount of 
water should not stop the action. 
