9 6 AN8WEES TO PRACTICAL QUESTIONS 



but it is in a more available form for communicating heat. 

 The steam in contact with incandescent charcoal is 

 decomposed the O going to the C to form CO 2 , and 

 the H being set free. If the C is abundant, and the heat 

 high, the CO 2 is also decomposed, and double its volume 

 of CO formed. The inflammable gases, H and CO, 

 mingled with the hydrocarbons always produced, are 

 ignited, making the billows of flame which sweep over 

 a burning building." S. P. SHARPLES. 



4. Why does the hardness of water vary in different 

 localities ? 



The hardness of the water will necessarily vary with 

 the solubility of the minerals in different localities. 



5. What causes the variety of minerals in the ocean ? Is 

 the quantity increasing ? 



The ocean contains the washings of the land. Every 

 mineral soluble in water is borne to the sea. The quan- 

 tity of mineral matter in the ocean would therefore seem 

 to be increasing, yet there is a compensation in the return 

 to the soil, of guano, marine plants, and fish, which are 

 driven on shore by winds and waves, or carried by the 

 industry of man. 



Analysis of sea-water (Schweitzer) : 



Water 963-74 



Sodium chloride 28.05 



Potassium chloride .76 



Magnesium chloride 3-66 



Magnesium bromide .02 



Magnesium sulphate 2.29 



Calcium sulphate i-4 



Calcium carbonate -03 



Iodine traces 



Ammonia traces 



