i88o.] 
On Water and A ir. 
55 
purpose of enabling you to repeat the experiment for your- 
selves. Here is a small beaker— a small glass, and we will 
put into it some chalk, and pour upon it a little hydro- 
chloric acid, and, as I have said, we shall have effervescence. 
There you see the mixture effervescing. Mr. Cottrell will 
pour into a beaker a quantity of lime-water, and allow the 
carbonic acid gas to bubble into it. There you see the gas 
is bubbling through the water, and you will find that the 
lime-water becomes milky as before. , T 
Here we have a bottle of champagne (b, Fig. 2 ), and I want 
to show you that we can make our carbonate of lime irom the 
carbonic acid issuing from champagne. This is a bottle ot 
Fig. 2. 
Mumm’s extra dry champagne. I will cut the wire and remove 
the cork. Here is a cork with a bent glass tube passing 
through it. We will put it into the bottle. The champagne 
is not very well up, so we will stir it a little. [1 he bent tube 
issuing from the neck of the champagne bottle was held 
with its farther end in a glass vessel of lime-watei (s), so that 
the gas given off by the champagne might bubble into the 
solution^ In a short time the lime-water became turbid, 
as in previous experiments.] Here we have got our chal c 
produced from the carbonic acid of the champagne. 
F And now I want to show you that carbonic acid is also a 
gas that we exhale from our lungs. I will take this small 
vessel and pour a little lime-water into it, and then simply 
blow into the vessel. We inhale the atmospheric oxygen, 
and, after this has done its work in the body by burning 
part of the body, we exhale carbonic acid. Here we shall 
have the carbonic acid coming from my lungs, which cai- 
bonic acid will unite with the lime in that water, and 
