Farms and Villages. 
29 
lost its bright and sparkling appearance, and became milky, in 
consequence of the carbonic acid gas having been driven off by 
the high temperature, and the insoluble chalk or carbonate of 
lime thrown down. To this action is due the heavy and de- 
structive sediments which choke up boilers and hot-water pipes. 
The sulphate and nitrate of lime, which are also commonly 
found in hard waters, are dissolved independently of carbonic 
acid gas, and are, therefore, not thrown down, except under 
very high temperatures due to high-pressure steam. 
Soft water readily produces lather with soap ; hard water, on 
the other hand, destroys much soap before a lather is formed. 
Soap may be regarded as a soluble compound of soda with 
fatty acids ; but with lime these fatty acids form insoluble 
-compounds, and hence it is that hard waters are deprived of 
lime, or softened at the expense of soap. The carbonate of 
lime in water used in washing decomposes about ten times its 
weight of soap, and the salts of magnesia act in a similar 
manner. 
Dr. Voelcker proceeded to enumerate the properties to be 
preferred in a water intended to be used for drinking and 
general household purposes ; these he stated to be : — • 
1. Freedom from putrescible organic matter. 
2. Freedom from constant, or even occasional discoloration 
by clay and vegetable matter, with perfect brightness 
and clearness. 
3. Freedom from smell and disagreeable taste. 
4. Softness. 
5. Coolness. 
In the examination of water, particular attention should be 
paid to ascertain the quantity of organic matter which a 
given sample may contain, and also to trace, if possible, the 
origin of organic impurities, and to determine whether they 
proceed from decomposing animal-refuse matters, or from harm- 
less vegetable substances. Wholesome and perfectly unob- 
jectionable waters are always bright and free from colour; but 
the converse is by no means true, for perfectly limpid and 
colourless waters may be dangerously contaminated. 
If water has a yellowish colour, and at the same time a more 
or less nauseous taste or smell, no chemical analysis is required 
to prove its unfitness as a beverage ; for such water is certain to 
contain decomposing organic matter of animal origin. Light 
floating particles of suspended organic matter also frequently 
afford indications of the unwholesome character of water. 
Dr. Voelcker goes on to describe how anyone may ascertain, 
by very simple experiments, the general character of a water, 
then gives instructions for sending samples up for analysis, and 
