SPRINGS. 27 1 



ever, in which the temperature is really different at different seasons, as measured by the 

 thermometer immersed in the water, alterations which are periodical in some cases, and 

 irregular in others. The following passage occurs in Lucretius : 



" A fount, 'tis rumour'd, near the temple purls 

 Of Jove Ammonian, tepid through the night, 

 And cold at noon-day ; and th' astonish'd sage 

 Stares at the fact, and deems the punctual sun 

 s Strikes through the world's vast centre, as the shades 

 Of midnight shroud us, and with gay reverse 

 Madden the well-spring : creed absurd and false." 



Pliny refers to this fountain, with some exaggeration, as cold in the day-time, and scorch- 

 ing hot at night ; and Ovid likewise : 



" Thy stream, O horn-crown'd Ammon ! in the midst 

 Chills us at noon, but warms at morn and eve." 



The alterations in the temperature of the fountain is analogous to that of the caverns 

 encrusted with ice in summer, and warm in winter, and may have been produced in the 

 same way by evaporation. 



5. Ebullient. Springs displaying violent ebullition, sending off vast clouds of steam, 

 and throwing up their scalding water to a considerable height in the form of a jet, are 

 the common phenomena of volcanic regions. In the island of St. Michael, one of the 

 Azores, there is a round, deep, and lovely valley, its sides covered with myrtles, laurels, 

 and mountain grapes, with wheat, Indian corn, and poplars waving upon its fields, in which 

 many boiling fountains occur. The principal, called tlae Caldeira, is on a gentle eminence 

 by the side of a river, and boils with great fury, and the river itself exhibits ebullition in 

 various places, where the water is too hot to be borne by the hand. But the most re- 

 markable of these springs are found in Iceland, and constitute, owing to their diversified 

 appearances, sublime, beautiful, and terrible objects in that strange region, where the 

 extremes of heat and cold, in the form of ice and fire, are in near proximity. They are 

 found in various parts of the island, but the chief are situated in its south-western division, 

 on a plain at the base of a low range of hills, about thirty-six miles from Hecla. Here, 

 within a circle of two miles, above a hundred are contained, some of which boil incessantly, 

 without any discharge of their contents, while others cast their waters high into the air. 

 To the principal of these springs the name of Geyser is applied a term derived from the 

 Icelandic geysa, signifying to burst forth with vehemence and impetuosity. There are 

 two, more remarkable than the rest, called the Great Geyser and the New Geyser, whose 

 columns of vapour are seen by the traveller long before he reaches their site. " At the 

 distance of several miles," says Henderson, " on turning round the foot of a high moun- 

 tain on our left, we could descry, from the clouds of vapour that were rising and convolv- 

 ing in the atmosphere, the spot where one of the most magnificent and unparalleled scenes 

 in nature is displayed." The Geysers are intermittent hot springs ; and on approaching 

 the Great Geyser, when in a quiet state, it presents the appearance of a large circular 

 mound, formed by the depositions of the fountain. Ascending the mound, a spacious 

 basin is seen, partly filled with hot water, clear as crystal, and gently bubbling. In the 

 centre there is a cylindrical pipe or funnel, about eighty feet in depth, and from eight to 

 ten feet in diameter, widening at the top, and opening gradually into the basin. The 

 inside exhibits a whitish surface, consisting of a siliceous incrustation, which has been 

 rendered smooth by the action of the boiling water. The basin is about 1 50 feet round ; 

 and, when full, the water it contains is about four feet deep, measuring from the surface 



