STUDIES IN NATURE 



have come out of the water. So when water 

 has travelled through chalk, there is a certain 

 amount of chalk in it which makes it feel hard 

 and rough to wash in, and will leave quite a 

 thick covering of greyish powder inside any pan 

 we use to heat it in. Rain-water has had no 

 opportunity of gathering anything out of the 

 soil, and the trace of gas it takes out of the air 

 as it falls to the ground does not injure it, though 

 in towns the air is often so full of smuts that the 

 rain-water there is too dirty to use. Indeed, it is 

 one of the blessings of a shower of rain that it 

 washes the air we are going to breathe, 



In medicinal springs, or in the natural mineral 

 waters, we have cases where the water in sinking 

 down into the earth has dissolved enough of the 

 substances through which it has passed for us 

 to notice, and for our bodies in some instances 

 to be able to profit by it. Such springs of water 

 are often found to be warm as well ; sometimes, 

 indeed, they are almost boiling, from which we 

 believe they must have come up from a great 

 depth, since the earth is found to be hotter the 

 further down we go into it. This warmth is 

 probably the reason why there is so much 

 mineral or other matter dissolved in them, since 

 most substances are dissolved far more easily in 

 hot than in cold water. 



Much that is of interest can be learnt from 

 watching the habits of animals with regard to 

 the times, places, and manner in which they drink. 



(92) 



