291 
In an experiment which may be considered an average one, 
before boiling, the hardness of the water was 183° 
After boiling 4 minutes, ... ihe ie MG 
iby 7 Tia ile yar) 20s, S| bee it Sane 
ee, Wi EMER Mea SP 
The hardness removed by boiling is called the temporary hard- 
ness, that which remains—the permanent hardness. 
Here it may be noted that soft water is not the best for making 
tea, for it draws out the woody flavour. This was observed by 
M. Soyer in the course of his experiments on tea-making. 
The use of soda neither improves the flavour nor the strength, 
it merely deepens the colour, although popular opinion has always,, 
and does now, maintain the contrary. 
We can well understand how it is, that when a town is 
supplied with water abounding in bicarbonates our boilers and 
heating apparatus suffer ; the water is benefited at the expense of 
the vessels in which it is heated, pipes are furred up, and frequent 
inspection and cleaning necessary to prevent danger. I believe 
that this cost alone would more than meet the expense of 
applying a general system of softening the water of the town. 
Purifying water on a large scale—Up to the present time this 
has been almost limited to the construction of filtering and 
settling beds attached to the reservoirs, and little has been done 
beyond the mere mechanical treatment of the water, and even 
this is very inadequate, owing to the fouling of the filtering 
media; but the time appears to be drawing near when the 
subject will be taken up by tke public generaily, and some 
method insisted on by which the chemical as well as the 
mechanical impurities of the water may be removed. 
Some few towns have adopted one of the systems now being 
recommended, amongst them Canterbury and the town of Henley- 
on-Thames, and the results have been eminently satisfactory. 
