96 



KNOWLEDGE 



[May 2, 1892. 



regarded as thermal springs, since they have derived their 

 exceptional heat from subterranean, and therefore extra- 

 meteoric, sources. 



The thermal springs of uon-volcanic countries, although 

 frequently but slightly heated, are in some respects the 

 most noteworthy, for the cause of their heat, not being 

 obvious, an attractive and interesting enquiry is suggested. 

 Such are the thermal springs of England and Germany. 



In England five have long been liuown. The most 

 famous and the hottest is that of Bath, which has a 

 temperature of 120^ Fahrenheit, and then follow those of 

 Buxton at 83% Clifton at 76', Matlock at 68", and Ashby- 

 de-la-Zouch at 62'^. Very similar in many respects to the 

 English springs are those of Germany, which have a 

 world-wide fame, and are the resort of an annually- 

 increasing number of both health and pleasure seekers. 

 The range of temperature of these waters is considerably 

 greater than that of our home springs, the Sprudel Quelle 

 of Carlsbad having a temperature of 167° Fahrenheit. 

 With the exception of the springs of Gastein, they are all 

 in three districts — Nassau, the Schwarzwald or Black 

 Forest (parts of Baden and Wurtemberg), and Bohemia. 

 Their temperatures are as follows : — 



Carlsbad, Bohemia (the Sprudel Quelle) . 167" F. 

 Wiesbaden, Nassau (the Kochbrunneii) . 158° ,, 

 Baden, Baden (the Ursprung) . . 153° ,, 



Toeplitz, Bohemia (the Stadtbad) . . 122° „ 

 Gastein, Austria (the Spltal Quelle) . 118° ,, 

 Ems, Nassau (the Kesselbrunnen) . . 118° ,, 

 Wildbad, Wurtemberg (the Furstenbad) . 98° „ 

 Schlangenbad, Nassau (the Altbad) . 86° ,, 



Liebenzell, Wurtemberg . . . 76° ,, 



Soden, Nassau ..... 75° ,, 

 Cannstadt, Wurtemberg .... 66° ,, 

 Hotter, however, than any of the above-named waters 

 is that of Abano, in North Italy, about live miles from 

 Padua, which has a temperature of 187 Fahrenheit. It 

 is true this place is at a seat of foriuer volcauic activity, 

 the Euganiau Hills, but the period of that activity was as 

 far back as Eocene times. 



One of the most remarkable examples of Hot Springs in 

 non-volcanic regions is that of Hammam-Meskhoutim, 

 near Constantine, in Algeria, where the water, with a 

 temperature of 203°, deposits calcareous travertine, and so 

 forms piles of basins rising to about 30 feet. Another 

 great deposit of travertine from such Hot Springs is at 

 Hierapolis, in Asia Minor, where it forms white terraces on 

 the side of the hill, on which in ancient times the water, 

 at about 100° Fahrenheit, issued. 



All these thermal springs, and many others in various 

 parts of the world, agree in issuing from the rocks of 

 regions of a markedly non-volcanic character, as those of 

 England, or of areas where volcanic activity is apparently 

 quite extinct. They all, therefore, require some hypothesis 

 to account for their high temperature other than proximity 

 to volcanic action. 



The theory founded on the ascertained increase of heat 

 with descent from the surface would put the source of the 

 Bath water at about 4000 feet depth. A much less depth 

 would be required by ascending hot fumes or gases meeting 

 with water, and so heating and impregnating it and 

 forcing it to the surface. The "physio-chemical hypo- 

 thesis" that accounts for the production of volcanic heat 

 at moderate depths by subterranean chemical action, when 

 the conditions are favourable, appears to meet the case of 

 the Bath waters, and thit of other thermal springs in 

 non-volcanic regions.* 



* Reports of the British Association, Bath Meeting, 1883, p. 670. 



One feature they have in common with all Hot Springs . 

 wherever they may be found and of whatever temperature 

 they may be, and this is that they are all more or less 

 " Mineral Springs," and it is to this fact, together with 

 their high temperature, that they owe their medicinal or 

 curative reputation. Water is at ordinary temperatures a 

 solvent of many substances, but at high temperatures of a 

 greater number, and, too, of a greater quantity of those 

 soluble in it when cold ; and boiling water is a solvent to 

 some extent of that usually most refractory substance, 

 sihca. Hence it is that boiling springs generally deposit 

 from their cooling overflow water the solid siUcious material, 

 silicious sinter. It has been estimated that the matter held 

 in solution by the Bath water, which has been derived from 

 the rocks through which it has passed, would, if solidified, 

 form annually a column having a base of nine square feet 

 and a height of 140 feet. This matter consists chiefly of 

 the sulphates of lime and soda and the chlorides of sodium 

 and magnesium. A spring at Clermont, in France, has 

 deposited a great mass of calcareous rock, forming a natural 

 bridge of travertine, and other examples have been pre- 

 viously mentioned. 



The thermal springs of volcanic regions which, from the 

 evident cause of their heat, may be called volcauic thermal 

 springs, are "very conspicuously different in character, 

 some being tranquil flows of heated water, some being in a 

 state of ebullition more or less active, and others, the 

 Geysers, being chai-acterized by periodic ejections or 

 eruptions of boiling water followed by violent explosions. 

 There are, too, many thermal springs where there is at 

 present no volcanic action, but yet these areas are so 

 volcanic in character, and have been the seat of volcanic 

 activity so late as post-Pliocene times, that the heating of 

 the waters issuing from their rosks can only be ascribed 

 to lingering volcanic fires. 



Of those regions the old province of Aus-ergne, in 

 France, is the most important in Europe. It has many 

 thermal springs, of which those at Vichy, Vic en Carladez, 

 Mont Dore les Bains, La Bourboule, and St. Nectaire are 

 best known. And in America Hot Springs are con- 

 spicuous in such areas, in Utah, near Salt Lake City, 

 where is Hot Springs Lake, and in Colorado, where are 

 the important Pagazo Springs, and especially so in 

 Wyoming. 



The oldest known and longest used Hot Springs are 

 those of the volcanic region of Southern Italy, where, near 

 Naples, these thenna:, so greatly used by the patricians of 

 old Roma, still give forth waters at the Baths of Nero, 

 near theLucrine Lake, of a temperature of 182° Fahrenheit, 

 and at Pisoiarelli, near the not yet quite extinct Salfatara, of 

 180° Fahrenheit, sufficiently hot, Dr. Daubeny found, 

 to boil an egg in a few minutes ; and across the blue 

 waters of the Bay of Naples, on the volcanic island of 

 Ischia, under the shadow of the slumbering volcano 

 Epomeo, there are the now much used hot baths of 

 Gurgitello. Some of the thermal springs of the remark- 

 able volcanic district of the Phlegrsean Fields are, 

 however, of but moderate temperatures. At Bagnoli, near 

 Pozzuoli, are two springs of 104° F., and the tepid 

 waters of Baife made that place great and rich in ancient 

 Roman times. 



But it is that northern, indeed Arctic land, Iceland, 

 of which most of us think when Hot Springs are 

 named, for of these phenomena the geysers of Iceland 

 received until recently the most prominent notice. 

 There are other Hot Springs in Iceland, but geysers, 

 or intermittent eruptive Hot Springs, are very numerous, 

 both in the Hecla district and in other parts of the 

 island. 



