362 On the Identity of Silex and Oxygen. 



culiar quartzy or rather sulphurous smell, already noticed ; 

 the effects produced by various species of phosphor! ; fric- 

 tion of two pieces of borax ; the electric nature of glass ; 

 that of amber, tourmaline, and of resinous bodies ; the 

 light evolved by friction and collision of bonnet-cane and 

 other vegetables which contain silex ; and, in short, all other • 

 analogous examples may be adduced as additional illustra- " 

 lions on this subject. 



If I were to select a case, in which silex seems to be de- 

 posited as it were, and deprived of the caloric which had 

 suspended it in the state of gaseous oxygen, it would be ^ 

 that of a natural hot-spring, such as the Bath-waters, which • 

 are confessedly impregnated with sand or silex, not merely • 

 in suspension as an accidental material, but perfectly dis--' 

 solved so as to be imperceptible to our sight. Besides these ^ 

 waters, all other hot springs contain silex In solution ; that 

 of Carlsbad; the Geyser, and Rykum, in Iceland; and many 

 others, which, it is said, issue, for the most part, from 

 granitic and other siliceous rocks. If these waters were cold 

 the argument might fail, but while the temperature of the 

 ambient medium can be taken into the account, I should 

 not be willing to retract this opinion, as far as it concerns 

 the nature of all hot-springs. It is f;tated from good autho- 

 rity, that in the kingdom of Portugal alone, there are up- 

 wards of 200 of these springs, the greater number of which, 

 and the hottest, originate where silex is most abundant. 



The presence of nitrogen in the Bath- waters, and, pro- 

 bably, in all other hot-springs, is a curious occurrence, and 

 furnishes a proper theme for speculation. Whether it be 

 the remainder of decomposed atmospheric air, which has 

 been bereft of its oxygen, and that this is disposed of 

 in the water, in the way I have supposed, is a question 

 I shall not urge. The late Doctor Black analysed the hot-' 

 springs of Iceland, but the analysis, I believe, was not 

 performed upon the spot, and, consequently, no notice 

 could be taken of nitrogen gas. In the gallon of Geyser 

 water, he found upwards of 31 grains of silex ; and in the 

 other, that of the Kykura spring, the proportion was 29 

 grains of the same ingredient in the English gallon. 



The 



