248 Contributions to Physical Geography. 



rapid effects of cold. The degree of perspiration in the heat- 

 ed baths varied very much in different persons, and was 

 greater in the dry than vapour stoves. Dr. Fordyce having 

 remained fifteen minutes in a vapour stove at a temperature of 

 130° (greatly lower than that of Nero's Baths,) his pulse rose 

 to 139, and he wa3 much more affected than by dry air of a 

 greatly higher temperature, which he justly imputed to the 

 heat given out by the steam, and to the want of evaporation 

 from the body, the air being in a state of saturation with mois- 

 ture. All the general phenomena experienced at the Stufe di 

 Tritoli are similar to those observed in the cases of artificial 

 experiment. The inflammation of the skin where exposed to 

 the steam is remarkable, and gives those who merely see the 

 guide return from the bottom a great idea of extreme tem- 

 perature. The streaming of condensed moisture from the 

 oodv has likewise the appearance of natural and excessive 

 perspiration, in which respect, however, as I have remarked, 

 people are very different. In my own case, the perspiration 

 was considerable, independant of condensed vapour. The ex- 

 treme narrowness of the passage, and the nearness of the 

 approach of the subterranean source of heat, preserve in these 

 singular and obscure grottos the most regular and intense 

 temperature, so that it is more insupportably hot at the turn 

 of the last branch, sixty paces from the spring, than over the 

 very steam as it rises from the water itself. The water is 

 brackish, but seems wonderfully little mixed with adventitious 

 matter. Fish boiled in it has no disagreeable taste. I regret 

 that I have no analysis to give of its contents. According to 

 the custom of the place, the guide takes some water in a pail 

 from the spring and puts fresh eggs into it, and, carrying them 

 to the open air, notwithstanding this effectual cooling, they 

 are in four minutes very pleasantly boiled. On leaving the 

 baths, I felt not the slightest disagreeable effect from almost 

 immediate exposure to the open air between 50° and 60°, but, 

 on the contrary, on re-embarking at the foot of the hill, expe- 

 rienced a delightful sense of warmth over my whole body. 



The quackery of guides and guide-books seems to have de- 

 terred our natural observers from inspecting this curious spot, 

 so near approached to that surprising focus which has main- 

 tained its intense temperature so many centuries, with unabated 

 vigour, without any indication, direct or indirect, of that mys- 

 terious fuel by which it has been fed, and which affords so re- 

 markable a subject of speculation in this age of geological 

 inquiry.* 



* Neither Professor Daubeny nor Mr. Scrope, our two principal volcanic 

 writers, seem to have visited these stoves. 



