58 
On Water and Air. 
[January, 
reservoirs is capable of containing 120,000 gallons of water. 
You go into a little adjacent, room and you see there a small 
reservoir, and in it you see a beautifully clear liquid ; but 
the probability is that in all the reservoirs you will see a 
beautiful white powder. The small reservoir is used purely 
for the purpose of making the lime-water. It contains the 
lime in a very fine state of division, and mixed with water, 
and therefore called “ cream of lime.” After being mixed 
with the water, the lime is allowed to stand, and the solid 
undissolved lime subsides to the bottom, and you have a 
beautiful transparent lime-water above. The hard water is 
pumped from the wells in the chalk, and is then allowed, 
first of all, to be mixed with a measured quantity of this 
perfectly transparent lime-water, for the proper quantity is 
perfectly well known ; and then instantly you have a 
beautiful fine whitewash produced in the reservoir, some- 
thing similar, in faCt, to this which has been produced in 
this vessel, and produced precisely in the same way. The 
mixture of the two transparent liquids produces this white- 
wash. The mixture is allowed to rest for twelve, or, better 
still, twenty-four hours. The carbonate of lime which 
has been liberated sinks slowly to the bottom, leaving a 
liquid of the most exquisite purity and softness on the top. 
The carbonate of lime is taken away, and the hard water is 
in this way converted into soft water. In the bottom you 
find a powder consisting of carbonate of lime ; and here, 
thanks to Mr. Homersham, I have some of that beautiful 
powder. It is as fine as the finest flour. Bakers in general, 
I believe, are thoroughly honest men, but one would not 
like this fine powder to fall into the hands of a thoroughly 
dishonest baker. It is so very like flour that he might 
materially adulterate his flour by means of this beautiful 
carbonate of lime. This is the carbonate of lime that has 
been separated from the chalk water at Canterbury, and 
deposited at the bottom of the reservoirs. 
But now the thought occurs to me, as I am speaking to 
you, to give you an opportunity of exercising this power of 
prediction, this power of prevision, of which I have spoken. 
And here I will take, first of all, a little of the lime-water 
and mix it with some distilled water. And here is some 
carbonic acid gas. Now I am going to ask you to turn 
prophets. When I allow the carbonic acid to enter the 
mixture of lime-water and distilled water, what you have 
already observed will occur. We shall have the liquid 
converted into a milky mass ; but will this be due to the 
