348 OLIVER: MINEEAL SPRINGS OF THE WEST RIDING. 
whether vegetable or animal — in the process of decay.* It has 
long been supposed that at the ordinary temperature peat, bog soil, 
or lignite will effect this reduction ; but experimenters have conclu- 
sively shown the groundlessness of this opinion.f The organic 
matter must be in a state of active decay. All the theories that 
hang on this explanation cannot, however, apply to the Harrogate 
sulphur waters, for soluble sulphates are not present ; and, if it be 
said they are absent because completely converted into sulphides, 
we can point to the ferruginous saline waters which are also sulph- 
ate — free. 
When the Sulphide of a mineral water can be traced to the 
reducing agency of decaying animal or vegetable tissue on soluble 
sulphates, these not only appear along with it, but some of the or- 
ganic matter also. This fact is well illustrated by the Strathpeffer 
sulphur waters, which contain from two to three grains of organic 
matter to the gallon.§ Not so the Harrogate sulphur waters, in 
which organic matter when detected at all has been recorded by 
analysts as mere traces — such as in fact appear very frequently in 
ordinary springs. 
(2) Decomposition of Iron disulphide — Pyrite (the form of 
sulphide of iron widely diffused through sedmentary beds, and 
frequently found in the lower carboniferous formations) is believed 
by some to yield a soluble sulphide when decomposed by carbonic 
acid and alkaline carbonates. But, I think, this source of sulphur- 
ation does not seem very probable when we call to mjnd that pyrite 
when free from marcasite (the less stable form of iron sulphide more 
particularly found in the secondary and tertiary fossiliferous rocks) 
resists weathering for very long periods — a fact indicative of its 
chemical stability — and that it has yet to be demonstrated that, in 
the absence of a temperature decidedly above the ordinary, it will 
* Strathpeffer is a good example of a sulphur water derived directly from 
a rock through which animal remains slowly decomposing are diffused — the fish- 
bed schist of the old red sandstone, a formation which when broken emits the 
peculiar foetid odour of decaying animal matter. See Old Red Sandstone by 
Hugh Miller. 
t See Lancaster. An account of Ashern and its Mineral Springs, 1842. 
Also E. Blanchard Compt. Bend., vol. 89. 
§ See The Sulphur Waters of Strathpeffer, by D. Manson, MA., M.D. 
