6 
Mr. Davy's Lecture on some 
continued to appear to the last, in quantities sufficiently 
distinguishable, and apparently equal in every case. I had 
used every precaution ; I had included the tubes in glass vessels 
out of the reach of the circulating air ; all the acting materials 
had been repeatedly washed with distilled water ; and no part 
of them in contact with the fluid had been touched by the fingers. 
The only substance which I could now conceive capable of 
furnishing the fixed alkali was the water itself. This water 
appeared pure by the tests of nitrate of silver and muriate of 
barytes ; but potash and soda, as is well known, rise in small 
quantities in rapid distillations ; and the New River water, 
which I made use of, contains animal and vegetable impurities, 
which it was easy to conceive might furnish neutral salts 
capable of being carried over in vivid ebullition. 
To make the experiment in as refined a form as possible, I 
procured two hollow cones of pure gold containing about 25 
grains of water each, they were filled with distilled water, 
connected together by a moistened piece of amianthus which 
had been used in the former experiments, and exposed to the 
action of a Voltaic battery of 100 pairs of plates of copper and 
zinc of 6 inches square, in which the fluid was a solution of 
alum and diluted sulphuric acid. In ten minutes the water in 
the negative tube had gained the power of giving a slight blue 
tint to litmus paper : and the water in the positive tube 
rendered it red. The process was continued for 14 hours; 
the acid increased in quantity during the whole time, and 
the water became at last very sour to the taste. The alkaline 
properties of the fluid in the other tube, on the contrary, re- 
mained stationary, and at the end of the time, it did not act 
upon litmus or turmeric paper more than in the first trial : the 
effect was less vivid after it had been strongly heated for a 
