340 ON THE PLACE OF FISH IN 



matter suspended or floating about in it. They of 

 course really do not form part of the water any more 

 than a boat floating on water does for when left at 

 rest, they settle down in the vessel containing the 

 water. By careful distillation an ordinary water can 

 be freed from almost all traces of matter it has 

 dissolved, and the Hydrogen-Oxide is left almost pure. 

 Even if the temperature is so reduced it becomes 

 solid it is still Hydrogen-Oxide, though in ordinary 

 language it is then called ice ; if the temperature is 

 so raised that it passes to the gaseous state it is still 

 Hydrogen-Oxide, though in ordinary language it is 

 called vapour. There are several ways in which 

 Oxygen and Hydrogen can be caused to unite to 

 form water, and ways in which water can be split up 

 into Oxygen and Hydrogen. Just as carbonic acid 

 results from the oxidation of Carbon, water results 

 from the oxidation of Hydrogen. 

 Water a loose The name Hydrogen-Oxide is an exact name water 



and inexact . 



name. is a loose and inexact name. Every one then is quite 



familiar with Hydrogen-Oxide though they know it 

 in its impure state and under the name of water, or 

 other native name for it, aqua, 1'eau, wasser, &c. 



Carbon, When some few facts like these are mentioned 



your " first man at the corner of the street " would no 

 longer regard Carbon, Hydrogen, Oxygen and Nitro- 

 gen as unknown strangers, even though their names 

 may cbme as new. 



To those not accustomed to considering foods as 

 consisting of so many ounces of Carbon, Hydrogen, 



Written for Oxygen, and Nitrogen, generally written for short 



short, C, H, Q H> o, and N,* the subject may at first sight seem 



* See note in Appendix. 



