J. P. Cooke, Jr., on Lecture Experiments. 191 
| one inch wide, The platinum conducting wires are welded* to 
the strips of foil and secured in the rubber stop- 2. 
os as represented in detail by fig. 2. Into the 
ower end of a short piece of glass tube, which 
passes tightly through the rubber, the platinum 
wire Connecting with the foil is secured by melting 
the glass around it, while the upper end is left 
open to receive the copper conducting wires from 
the battery, and the connection is made perfect by 
Placing a few drops of mercury in the tube. This 
simple form of connecting-cup is easily made and 
very convenient. 
the condueting power of hydrochloric acid is very good, 
) three Bunsen cells of the ordinary size have ample intensity and 
give a rapid evolution of gas. The hydrogen gas is conducted 
mto a tall but narrow glass jar mounted in the usual way over 
asmall pneumatic trough, while the chlorine is collected by dis- 
3. placement in a precisely similar jar mounted as rep- 
ane resented in fig. 8. The mouth of this jar is closed 
f by a ground glass plate, which is tubulated, as is 
. shown in detail by fig. 4. This tub- rf 
E ulature again is closed by a rubber 
stopper, through which pass first, the 
delivery tube, which reaches the bot- 
tom of the jar, and secondly an over- 
ow tube which merely passe 
through the stopper, and which in 
the experiment should be connected 
by a flexible hose with a ventilator. 
When i 
i with a second, and that with a third, ete., all —— 
Jar leading to a ventilator as before. When the 
~~ jars are full the tubulated stoppers with their con- 
Rections are removed and a plain glass cover substituted. T 
elded to the foil on a smoothed surface of a 
hich serves as an anvil. The two having been placed tog a 
uired position on this support are first intensely heated at the point 
ith a blow-pipe flame, and then a quick blow with a small 
the work. 
