DAVIS : MINERAL WEALTH OF HAEEOg-ATB. 
365 
Lime sulphate must of necessity enter largely into the compo- 
sition of the superficial stratum in the neighbourhood of our sulphur 
waters, owing to the decomposition of the sulphur precipitated from 
the overflowing water by exposure to the atmosphere. It would 
appear, therefore, that as our waters approach the surface, they are 
liable to admixture with water charged with lime sulphate percolating 
downwards, and if a preponderance of sulphate is present, the barium 
may be expected to disappear from solution, but the usual changes 
observable in adding solutions of these two salts do not occur with 
anything like such rapidity as may be observed in a laboratory. 
When the water of the Old Sulphur Well containing barium 
carbonate in the proportion of 6.173 grains per gallon, and of the 
New Sulphur Well water containing 15.89 grains of lime sulphate 
per gallon are mixed together no precipitation occurs within 24 
hours, and the water will remain bright for some time ; after a week 
or so the usual double decomposition takes place, but the precipitate 
assumes a different character to what is usually observed, it is 
semi-crystalline. Previous to this interchange, the water is in the 
anomalous condition of giving reactions with solutions of either salts 
of sulphuric acid or barium. 
I venture to suggest that this inchoate or nascent condition 
may be favourable for the deposition of the insoluble salt, and 
explains the occurrence of \he baiium sulphate mentioned by Dr 
Thorpe, as existing in considerable quantity in the cracks and fissures 
of the sandstone in this district.* 
As a counterpart to the instance I have given with regard to 
the Harrogate Spas of the delayed action when conflicting constit- 
* In the proceedings of the Newcastle-on-Tyne Chemical Society, some 
years since, there is an account of a deposit which had formed in a water box in 
the shaft of a coal-pit in that locality. The box had been filled np mitil its 
sectional area was reduced from 7^ square inches to less than half a square inch; 
on submitting this deposit to analysis, it was found to consist of 90 per cent, 
barium sulphate, 8 per cent, strontium sulphate, the rest calcium sulphate, silica, 
alumina, and ferric oxide. The water on analysis was tound to contain small 
quantities of ferric oxide, sihca, alumina, and sulphuric acid, a moderately 
large quantity of calcium carbonate, and a large amount of potassium and sodium 
chlorides ; total solids about 800 grains per gallon. The analyst, Mr. J. T. Dunn, 
states that although about two gallons of the water was evaporated, no trace of 
barium or strontium could be found. This furnishes another instance of the 
disappearance of constituents which must have existed in considerable quantities 
in the water to have formed such a large deposit. 
