112 THE WONDERS REVEALED
whether in air or water. These two gases form water, by combustion."
" How wonderful !v exclaimed Lewis, " for water, you know, papa, extinguishes fire."
" It is, indeed, astonishing, Lewis : there is no end to the wonders which the knowledge of chemistry reveals, and no doubt will continue to reveal to us. But, now tell me, Lewis, have you ever seen water in any other than a fluid state ?"
" Oh ! yes, papa, frozen water is quite solid; it then becomes ice."
" And," interrupted Helen, " heated water becomes steam or vapour; though I recollect mamma's telling me, that it was a fluid still; and that even the air which surrounds us is a fluid, like water, only much less