ELECTROCHEMISTRY RICHARDS. 173 



this city. At McKeesport tubes are coated on an immense scale, 

 by dipping into melted zinc, but the electrolytic method is gaining a 

 foothold, and we may live to see all galvanizing in reality practiced 

 as it is spelled. The removing of metallic tin from waste tin scrap is 

 also accomplished on a large scale by the application of similar prin- 

 ciples. It is being operated at a distance from Pittsburgh, but your 

 open-hearth furnaces use up annually thousands of tons of the scrap 

 steel thus cleaned and saved for remanuf acture into useful shape. 



Without having mentioned or described more than a fraction of the 

 electrolytic methods in actual industrial use, I hope that I have made 

 clear the importance and extent of this land of electrochemical proc- 

 esses. Assuming this, we will pass to the consideration of another 

 entirely different and yet important class of apparatus and processes. 



II. 



Electric arcs and high-tension discharges through gases are capable 

 of producing some chemical compositions and decompositions which 

 are very useful and profitable to operate. This is a branch of electro- 

 chemistry which has not been as thoroughly studied as some others, 

 its phenomena are not as thoroughly under control as electrolysis and 

 electrothermal reactions, and its possibilities are not as thoroughly 

 understood or utilized. 



Ozone is being made from air by the silent discharge of high-tension 

 electric current. The apparatus is so far simplified as to be made in 

 small units suitable for household use, ready to attach to a low-tension 

 alternating current supply. The uses for the ozone thus produced 

 are particularly for purifying water and air. It makes very impure 

 water perfectly safe to drink and purifies the air of assembly halls 

 and sick rooms, acting as an antiseptic. According to all appear- 

 ances, this electrochemical doubling up of oxygen into a more efficient 

 oxidizing form is developing into a simple and highly efficient aid to 

 healthy living. 



Nitric acid is an expensive acid made from the natural alkaline 

 nitrate salts, such as Chili saltpeter. These nitrates are the salvation 

 of the agriculturist, for they furnish the ground with the necessary 

 nitrogen which plants can assimilate. The Chili ''nitrate kings" 

 have gained many millions of dollars, even hundreds of millions, in 

 thus supplying the world's demand for fertilizer. But electro- 

 chemistry has another solution to this problem, which is rapidly 

 rendering every country which adopts it independent of the foreign 

 fertilizer. The air we breathe contains uncombined nitrogen and 

 oxygen gases, which, if combined and brought into contact with 

 water, furnish the exact constituents of nitric acid. The way to do 

 this has been laboriously worked out, and the electric arc is the agent 

 which does it. Air is simply blown into the electric arc, where it for 



