i I4 On Water and Air . [February, 
ring. The sound is not quite dead. [The water having 
been brought into the leg of the tube (a b), the tube was 
gently tapped on the lecture table, so as to cause the water 
to adhere more closely to the interior.] Now the sound is 
very dead indeed ; and I have got the water in contact with 
the tube that contains it. Now I will lift it up carefully, 
Fig. 4. 
and you observe that the water no longer stands at the same 
level in both tubes, but fills the leg of the tube A B altogether 
and leaves the other quite empty, and that is because of the 
tenacity of the particles of the water which are clinging to 
the sides of the tube, the water having been deprived of 
its air. 
Now, let me be perfectly exadt. I have said that the 
water gets rid of this air by boiling ; but some years ago a 
series of experiments was made by Sir William Grove, 
which seemed to show, or which at least justified him in 
saying, that he believed that we never saw boiling water at 
all in the proper sense of the term. He has sometimes 
boiled water not for hours only, but for several days. When 
you rid water of its air, as M. Donny did, you can heat it 
to a temperature far beyond the ordinary temperature of 
boiling water, and from time to time it gives as it were a 
