272 NEW ZEALAND NATURE-STUDY BOOK 
In the case of brine springs the liquid is pumped into 
large flat metal pans. Under these fires are kindled — 
and the water is gradually driven off, leaving the Salt 
behind. This has to be freed from impurities before being 
used. 
Sea-water contains about 34 per cent. of solid matter in 
solution, the greater portion of which is Salt. In certain 
places this fact is made use of in obtaining the mineral. 
The water is led into shallow tanks, where it is allowed 
to remain until the heat of the sun brings about the 
necessary evaporation—or it is pumped into metal tanks 
and heated as described above. The Salt obtained from 
sea-water is brownish in colour and coarser and darker 
than common Salt—it is known as Bay Salt. 
Novs.—In sea-water there is a large amount of dissolved mineral 
matter in addition to Salt. This and other impurities have to 
be got rid of before the Salt is fit for use. 
Uses. We are all familiar with the uses of Salt as 
food and in cooking. As food it is absolutely necessary 
_—it supplies some of the mineral matter required by the 
body, and largely aids in the process of digestion. It 
flavours or gives a taste to much of what we eat—eggs, 
potatoes, butter, porridge, are insipid without the addition 
of Salt. In cooking, too, it is very largely used for the 
same reason. 
Then, again, it preserves animal substances—meat, fish, 
butter, can all be made to keep for a considerable time 
without becoming tainted, by the addition of Salt. 
For other uses see Rock Salt, page 269. 
