REPOKT ON MINERAL AND THERMAL WATERS. 59 



principles to the case of springs, by espying difficulties in cer- 

 tain special instances to the application of the received theory. 



It may, however, be sufficient for my purpose to remark, 

 that, be the difficulties in question real or apparent, they are 

 not, at least, of moment enough, or applicable to a sufficient num- 

 ber of cases, to induce more sober theorists to adopt the views, 

 which it has been proposed to substitute for the received ones. 



The majority of naturalists will be contented with appealing 

 to the researches of Dr. Dalton, who, in a paper published in 

 the Manchester Memoirs*, has shown the adequacy of the water 

 ^vhich descends from the heavens in the part of England he 

 inhabits, to supply the springs of that district, notwithstanding 

 the loss arising from evaporation. 



There appears indeed, from his calculation, to be an excess 

 of 2 inches per annum in the latter beyond the amount of rain 

 and dew which fall ; but this excess Dr. Dalton thinks may be 

 explained without resorting to any other supposition than the 

 one alluded to. 



Yet, although the general theory will scarcely admit of dis- 

 pute, it is satisfactory to collect facts on this subject, in order 

 to compare with the former ; and one singularity has been ob- 

 served in the instance of springs issuing from chalk, which appear 

 to be most copious in June, and least so in Decemberf. 



This, however, seems referable to the slowness with which 

 water percolates so thick a stratum as the chalk, and is analo- 

 gous to what has been observed with respect to terrestrial heat, 

 where the excess of summer temperature does not reach the 

 utmost limit of its progress into the earth till about the middle 

 of winter. 



Mr. rienwoodj has also stated the quantity of water given 

 out by the springs in a certain district of Cornwall, as deter- 

 mined by the amount raised by the engines in particular mines ; 

 and concludes, that it is greater by one third than that of the 

 rain falling in the country. 



This, however, may easily arise, owing to the mines drawing 

 water from a much larger surface, than the area of country di- 

 rectly overlying them, Avhich, as being the deepest spots for a 

 considerable distance, they may readily be conceived to do. 



To descend from the general theory of springs to the causes Origin of 

 of their particular characters, I will first notice the circumstance "i'^.'''"*' 



e I. J. springs. 



or temperature. 



* Vol. V. See also A.rago on Artesian Wells, in the Ammaire for 1835, 

 translated in Jameson's Journal. 



t Bland in Phil. Maijuxine for 1832, p. 38. 



+ Phil. Magazine, New Scries, vol. i, 1832, p. 287. 



