122 
HUDLESTON : EXCUKSION. 
temperature is evidently pretty nearly that of the air, so that no 
appreciable amount of extraneous heat can be detected. Indeed, 
it may be said that all the waters of Harrogate are " cold," and, 
with one exception (the Alum Well), they have all a markedly 
alkaline reaction. Roughly calculating- the Old Sulphur Well 
would yield seven tons of chlorides per annum, including 100 lbs. 
of Barium Chloride,* and 37 lbs. of Magnesium Bromide, with 
some Iodide. It would also produce 240 lbs. of Sodium Hydrosul- 
phide (NaHS.) 
The origin or source of these abundant impregnations has 
naturally been a matter of considerable difficulty. The most 
probable explanation is that the springs, though not superficial, are 
far from being deep-seated, and that the water supply comes 
mostly from the Harlow Hill district, which attains 600 feet 
elevation, and attracts a rainfall that cannot well average less than 
35 inches annually. That the supply is not superficial may be 
inferred from the fact that the drainage from the Bog Field had no 
effect on the deliver}^ of the waters, and thus the notion, held by 
Phillips, as to the bog origin of the sulphur waters Avould seem to 
be untenable. The large quantity of chlorides look very much as 
if a portion of the water of the sea or of an estuaryf had been 
evaporated and the salts incorporated with the Yoredale Rocks 
during their formation. There is abundant evidence, both in this 
neighbourhood and elsewhere, of the quantity of organic matter, 
* Barium Chloride was not noticed by Hoffmann, in 1S54 ; and that chemist 
only found traces of Bromides and Iodides. Improvements in methods of 
analysis may account for the dift'ercnce. 
t The total Solids of the Mediteiranean compared with those of the Baltic, 
present the following per centage differences. ('Bischof, Vol. 1.) 
Mediterranean. Baltic. 
Sohds 3-77 1-77 
Haloids 89^ 94^ 
Sulphates 10| 5 
Carbonates -| ^ 
4-77^ 2-77 
