140 SPRINGS, RIVERS, CAN ALS, 



SECTION VI. 



Alternating Hot and Cold Springs. 



THERE are many tepid springs which, without any real change 

 in their temperature, appear to the people that frequent them to be 

 much warmer in the winter than in the summer. Of these we have 

 already given an example in the preceding section, in describing the 

 warm springs in the district of Troas. The apparent variation in 

 such cases depends altogether upon the real variation in the tempe- 

 rature of tile atmosphere : the water sinking the thermometer be. 

 low the temperature of the surrounding air in summer, but raising 

 it perhaps twenty or thirty degrees above that of the winter season. 



There are other springs and fountains, however, in which there 

 is a real difference in the temperature of the water at different sea- 

 sons, as measured by the thermometer when plunged into the water 

 itself: and while in some instances these alterations are irregular, in 

 others they are fixed and periodical. Botli these facts have been 

 known to natural philosophers through a long series of ages; and 

 the last is thus minutely exemplified by Lucretius in his Nature of 

 Things, vi. 848. 



Esse apud Hammonis * fanum funs luce diurnd. 

 Frigidus, ct calidus nocturno tempore, fertur, 

 Hunc homines funtem minis admirantur, et acri 

 Sole putaiit subter terras fervescere parting 

 Nox ubi terribiii terrain caligine texit : 

 Quod nimis a ver& est longe ratione reraotum. 



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

 Of. JOVE AMMONIAN, tepid through the night, 

 And cold at noon-day ; and th* astonished sage 

 Stares at the fact, and deems the punctual sun 

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

 Of midnight shroud us, and with ray reverse 

 Madden the well-spring: creed absurd and false. 



GOOD. 



'!M.J""- ' ' ' ' ~ ' " "' " ' 



* We quote from Wakefield's edition 



