ABOUT COMMON WATER. 333 



and tasted, and weighed^ must have escaped from the 

 towel in this invisible way. How, then, can you ex- 

 pect me to show you the atoms, which, as they are the 

 first beginnings of things, are probably much smaller 

 than your " invisible " particles of water ? ' 



In this invisible state, to which water may be re 

 duced, it is called aqueous vapour. 



Let it then be admitted that water rises into the 

 air by evaporation ; and that in the air it forms the 

 clouds which discharge themselves upon us as rain, 

 hail, and snow. If you look for the source of any great 

 American river, you will find it in some mountain-land, 

 where, in its infancy, it is a mere stream. Added to, 

 gradually, by other tributary streams, it becomes 

 broader and deeper, until finally it reaches the noble 

 magnitude of the Mississippi or the Ohio. A consider- 

 able portion of the rain-water sinks into the earth, 

 trickles through its pores and fissures, coming here and 

 there to light as a pellucid spring. We have now to 

 consider how * spring-water ' is affected by the rocks, or 

 gravel, or sand, or soil, through which it passes. 



The youths who choose this journal for a 'com- 

 panion ' know already that Mrs. Tyndall and myself are 

 lovers of the highlands. I tried last year to give them 

 some notion of ' Life in the Alps.' Well, here in Eng- 

 land, Alpine heights are not attainable ; but we have 

 built our house upon the highest available land within 

 two hours' of London. Thousands of acres of heather 

 surround us, and storms visit us more furious than 

 those of the Alps. The reason is, that we are here on 

 the very top of Hind Head, where the wind can sweep 

 over us without impediment. 



There is no land above our house, and therefore 

 there are no springs at hand available for our use. 

 But lower down, in the valleys, the springs burst forth, 



