30 PROCEEDINGS COTTESWOLD CLUB 1918 
from 100 to 3,000 grains per gallon, and it is a consideration 
of these facts which will occupy our thoughts this afternoon. 
The term Mineral Waters is by no means a suitable one, 
it would be far better to describe them as Medicinal Waters, 
and this being so it will be advisable to consider what are the 
curative substances present. 
Until quite recently the amount of common salt present 
was the deciding factor in estimating the value of a mineral 
water, but this practice has been abandoned, and now its 
absence, or its smaller quantities, is looked upon as a merit. 
Yet this attitude is not altogether right, as common salt is 
always accompanied by traces of Bromides and Iodides, both 
of which are considered as having curative properties. 
The following salts have generally been assumed to have 
some medicinal value : — 
The Sulphates of Sodium, Magnesium, Potassium, Ammo- 
nium, and Lithium. 
Carbonates of Sodium, Magnesium, Lithium, and Iron. 
Bromides and Iodides of Potassium, Sodium, and 
Ammonium. 
Chlorides of Lithium and Magnesium. 
Sulphuretted Hydrogen and 'Radioactive bodies. 
As to which of these is most valuable I cannot undertake to 
say. I have had the advantage of hearing the opinions of 
medical experts at Cheltenham, Bath, Llandrindod, and 
elsewhere, and for more than twenty years have been employed 
both at Llandrindod Wells and Llanhurtid in advising as to 
the composition of the water. The impressions I have received 
are as follows : — 
Sodium sulphate and sulphuretted hydrogen are most 
important, and as the former salt is decomposed in the intestines, 
yielding sulphuretted hydrogen, it may be that this gas is the 
real curative agent. 
The Magnesium salts, both sulphate and carbonate, are well- 
known medicines. 
Iron salts are regarded as tonics. 
Lithium is thought to be specific for uric acid troubles. 
Iodides and bromides are beneficial in the cure of eczema. 
